author2
133CommentsSouthern California, USAJoined December 1st, 2014
After 29 years as an Electrical Engineer performing digital and analog hardware design and programming - specializing in Embedded Systems Engineering, I'm retired. That allows me to enjoy my passion for sailing (year round here in Southern California)! I still find time to dabble in DIY projects, mentor startups, design hardware (and program it) for people or just for fun. You know the mantra - if it ain't broke, take it apart and make it better.

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100+ Comments Earned a bronze medal
  • Motion Follow Animatronics Eyes

    I LOVE it!All kinds of Halloween ideas...This might be the project that makes me buy a 3D printer.For anyone doing any kind if project with RC servos, I highly recommend a “servo tester”.They are not expensive and allow you to do all kinds of testing (like limits, binding etc.) without messing around with scripts.There are tons of manufacturers and levels of sophistication - some allow you to see/set the PWM value digitally.Here’s a link to the cheapo one I have.(I can’t believe this vendor is selling a three pack for much less than I paid for one).https://www.amazon.com/Ximimark-Digital-Consistency-Controler-Checker/dp/B07JVK7PVP(I have no affiliation with or connection to this vendor).

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  • DIY Mini UPS for WiFi Router / Modem

    Nice idea of an easy way to determine Watts of laptop without having to measure Amps. How long does the known quantity battery lasts... I like it.of course if laptop battery is not fully charged when power goes out, the laptop will consume (significantly?) more than the approximately 8W in your example because we need to power the laptop and charge the battery.of course in this scenario, the laptop was plugged in all the time, so the battery would be fully charged. But if it’s not... I guess you need to determine how long it takes to fully charge to determine the watts going into the battery while charging and add that to the number you determined for the laptop.

    Agreed. After a power outage that drains the battery (hopefully the device does it’s job and gets you through the blackout), when power comes back the charger will be putting out 1A - probably at a lower voltage than 3.7v. But your boost regulators are drawing more than an amp. Which means... you’re going to continue to discharge the battery.In fact, starting out with a full battery, it will discharge during use, even if charger is plugged in.(for me, it’s easier to convert everything to watts, then you don’t have to keep putting voltages into your calculations.).in this case, you’re charger is putting in 5W.your router (if it really draws an amp at 12v) is drawing 12W.As Frarugi87 points out, the math just doesn’t work for using it as UPS.The router would need to draw less than about ...

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    Agreed. After a power outage that drains the battery (hopefully the device does it’s job and gets you through the blackout), when power comes back the charger will be putting out 1A - probably at a lower voltage than 3.7v. But your boost regulators are drawing more than an amp. Which means... you’re going to continue to discharge the battery.In fact, starting out with a full battery, it will discharge during use, even if charger is plugged in.(for me, it’s easier to convert everything to watts, then you don’t have to keep putting voltages into your calculations.).in this case, you’re charger is putting in 5W.your router (if it really draws an amp at 12v) is drawing 12W.As Frarugi87 points out, the math just doesn’t work for using it as UPS.The router would need to draw less than about 0.25A for the math to work.it will make a very nice power bank, though.

    See my post above. I guessed the laptop draws 2A. If I’m wrong, adjust my numbers accordingly.With my assumed 2A, you need one hundred 18650 cells.you also need a boost regulator that can handle 10A in and 2A out.If I was trying to do what you want to do, I’d definitely go with deep cycle car batteries.I think a large car battery is something like 100Ah. At 12V, that’s 1200Wh.We “only” need 864Wh, so one large car battery could do the job.smaller car batteries are more like 40Ah, so you’d need three.get a battery (sears)get a trickle charger (harbor freight)get your boost regulator - which now only has to handle about 3A in (eBay)some connectors...a lot lot cheaper and easier than 100 18650’s.and perhaps safer (100 18650’s multiplies that risk of a LiIon cell doing something nasty by 10...

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    See my post above. I guessed the laptop draws 2A. If I’m wrong, adjust my numbers accordingly.With my assumed 2A, you need one hundred 18650 cells.you also need a boost regulator that can handle 10A in and 2A out.If I was trying to do what you want to do, I’d definitely go with deep cycle car batteries.I think a large car battery is something like 100Ah. At 12V, that’s 1200Wh.We “only” need 864Wh, so one large car battery could do the job.smaller car batteries are more like 40Ah, so you’d need three.get a battery (sears)get a trickle charger (harbor freight)get your boost regulator - which now only has to handle about 3A in (eBay)some connectors...a lot lot cheaper and easier than 100 18650’s.and perhaps safer (100 18650’s multiplies that risk of a LiIon cell doing something nasty by 100).Or you could just buy a commercial UPS that is rated at 1000Wh.Hmmm. After some googling to see how expensive that would be, I see that UPS vendors rate them by Watts and/or VA - which is how big a load it can handle.it gives you no indication of time.

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  • RicksterInstructables commented on Nick70587's instructable Magnetic Laptop Mount2 months ago
    Magnetic Laptop Mount

    Where’d you get the super strong magnets?

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  • Secret Dual USB Data Vault

    Wow, talk about 64GB in a five pound bag!Nice idea, nice design, beautiful implementation.and I t’s not really a dummy drive. It works, right?so you have two selectable drives.the dummy drive is for your “protected work” stuff.the hidden drive is for your NSFW etc. or the manuscript on how you have developed cold fusion...One caution,your drives are identical.the probably present the VID (vendor ID) and PID (product ID) to your os.if they are the same (and you can verify this from hardware manager on one of the pull downs on the drive) I think you risk the os getting confused if you ever switched drives with it plugged in - the system might not notice the change - does it “di-dunk” and then “do-dink”?if so, it probably noticed the drive change, but your not out if the woods.you didn’t e...

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    Wow, talk about 64GB in a five pound bag!Nice idea, nice design, beautiful implementation.and I t’s not really a dummy drive. It works, right?so you have two selectable drives.the dummy drive is for your “protected work” stuff.the hidden drive is for your NSFW etc. or the manuscript on how you have developed cold fusion...One caution,your drives are identical.the probably present the VID (vendor ID) and PID (product ID) to your os.if they are the same (and you can verify this from hardware manager on one of the pull downs on the drive) I think you risk the os getting confused if you ever switched drives with it plugged in - the system might not notice the change - does it “di-dunk” and then “do-dink”?if so, it probably noticed the drive change, but your not out if the woods.you didn’t eject the dummy drive before switching which can be bad.strongly suggest setting to the desired drive before inserting.eject when done.if you want to change drives, eject the one that’s inserted, code in the second and reinstall.of course eject that one when done.

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  • Portable Indoor Light With 100W LED Chip

    I don’t see much in the way of “current limiting power supply” on the units you URLed.Do you get much flicker driving them from AC (I do maybe see a bridge rectifier on them)?

    I read all electronics Instructables with trepidation. As a thirty five year veteran designing consumer electronics, I’m always concerned with the safety of projects that are obviously designed by someone who doesn’t know the basics and/or details of what they’ve instructed. Then, it might be copied by a subscriber with even less understanding.Ironically, in all the worst instances of this, we invariably see the author come back fighting if any electrical engineer makes (valid) comments about the post.My hope us that Authors will realize that the Instructables community has a lot of experts on just about every topic.Authors aren’t expected to be experts at every turn (It’d be great if every electronics Instructable didn’t make me cringe...).Should be ready to accept suggestions from oth...

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    I read all electronics Instructables with trepidation. As a thirty five year veteran designing consumer electronics, I’m always concerned with the safety of projects that are obviously designed by someone who doesn’t know the basics and/or details of what they’ve instructed. Then, it might be copied by a subscriber with even less understanding.Ironically, in all the worst instances of this, we invariably see the author come back fighting if any electrical engineer makes (valid) comments about the post.My hope us that Authors will realize that the Instructables community has a lot of experts on just about every topic.Authors aren’t expected to be experts at every turn (It’d be great if every electronics Instructable didn’t make me cringe...).Should be ready to accept suggestions from others who might be expert at what the speak.Coming out fighting that you can “touch” it for two seconds - well it’s just silly.

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  • Easy Way to Smooth PLA | No Sanding

    I’m pretty sure the requirement for ID to purchase spray paint is to help discourage “tagging” (graffiti). Though it may be to reduce the use of spray paint for “huffing” (inhaling for “intoxication” high). Which reinforces your concern that it’s toxic...Used in a well ventilated area should prevent inhalation of the toxic VOCs.Once dried, I think spray paint is pretty inert.

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  • How to Fix Corroded Battery Terminals

    The absolute best thing you can do is to buy a small jar of Caig De-Oxit D100.(https://www.amazon.com/CAIG-Laboratories-D100L-2DB-Electric-Cleaner/dp/B0002BBVN2). Buy the small bottle that comes with an applicator brush in the cap.It may seem expensive, but a little goes a long way and it will last you for many years.It prevents corrosion of the terminals. It helps clean corroded ones.You will never have to “shake” a flashlight again to get it to work.Any/every time I install or replace batteries I always put some on the terminals and the ends of the batteries.You can thank me later!

    That’s odd. I’ve never seen a “copper top” leak/corrode and now use them (or the new quantums exclusively.I’ve seen way too many pink bunny battries leak...When I buy something (like a TV remote) that comes with batteries, I always throw those questionable,ones away and use copper tops.

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  • Clear Sink Clog - FAST, NO BUCKETS, NO CHEMICALS

    You failed to mention the hardest part.When you reinstall the lifter rod, it has to pass through the hole in the tab at the bottom of the drain plug.Put the stopper in the sink, with the tab towards the “back”.Then insert the lifter rod with it angled slightly downwards (as if the sink handle for it is pulled up a bit.)Wiggle the sink drain handle to ensure correct operation, then tighten the nut holding the lifter ball joint into the drain. Don’t overtighten.NOTE:I myself, would never shove clog like material down the drain. That’s just asking for more complex problems that might/will require a plumber.Warning. Serious grossness factor.There is undoubtedly a large bundle of slimy, smelly disgusting hair caught on the lifter rod.In my family, due to the grossness factor, this is a defin...

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    You failed to mention the hardest part.When you reinstall the lifter rod, it has to pass through the hole in the tab at the bottom of the drain plug.Put the stopper in the sink, with the tab towards the “back”.Then insert the lifter rod with it angled slightly downwards (as if the sink handle for it is pulled up a bit.)Wiggle the sink drain handle to ensure correct operation, then tighten the nut holding the lifter ball joint into the drain. Don’t overtighten.NOTE:I myself, would never shove clog like material down the drain. That’s just asking for more complex problems that might/will require a plumber.Warning. Serious grossness factor.There is undoubtedly a large bundle of slimy, smelly disgusting hair caught on the lifter rod.In my family, due to the grossness factor, this is a definite “dad” thing, (though my hair is not the culprit).Find a way to lift the huge ball of slimy hair out of the drain.I do it before removing the lifter or stopper.Amazon, Home Depot etc. sell these very inexpensive plastic things that are just a thin strip of plastic with “teeth” on the sides. Search “drain zip”.Slide it into the drain alongside the stopper and lift it out. Be prepared to say “ewww” as you remove it with all the slimy biofilm caught in the teeth.After getting the majority out, then remove the lifter and stopper as explained in this Instructable.

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  • Homemade Tin Can Turbine With 3d-printed Compressor

    I absolutely LOVE this Instructable.It shows a lot of ingenuity and is well presented.I've always dreamed of building a jet engine, though I have absolutely no use for one.Now I feel that I've built one vicariously through you!

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  • How and When to Water Your Houseplants

    When people ask my mom (a "Master Gardener") why their xyz plant died, she always answers,"Well, you either over watered it, or under watered it"."How do I know which?""You really can't tell."

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  • High Voltage Alternating Occlusion Training Glasses  [ATtiny13]

    Ah yes. Excellent point.Whenever I see lots of discretes, I can't resist looking for an integrated solution.I looked for a FET solution, but they were all overly complex.

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  • High Voltage Alternating Occlusion Training Glasses  [ATtiny13]

    I like the way you did the voltage multiplier.Did you consider using a dual-h-bridge motor driver to replace ALL of your transistors and many resistors? I did some googling and found a part that I think would work nicely. It's a single so-8 package.LV8548MC (or pin compatible LB1948MC).

    oops. so-10 package.

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  • RicksterInstructables commented on bcb10's instructable ATTiny EMF Detector1 year ago
    ATTiny EMF Detector

    Nice.Where did you get those LEDs (that "stack" so nicely?Did you file them down?

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  • Make Golden Coins (really Easy)

    I'm wondering the same thing about US-American pennies.Would the copper plating fuse to the zinc core?

    Cool idea!You might update the Instructable to mention that you're forming brass by fusing zinc and copper.I had no idea how the "silvery" coins turned "golden" until I read the comments.

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  • Super Glue Accelerator and Filler

    Thank you for the Instructable.I sometime use wads or pieces of paper towel.It cures astonishingly fast.It produces a result that can be cut/shaped with a knife or sanded.And I feel that the paper fiber add strength.

    Thank you for the Instructable.I sometimes use wads or pieces of paper towel.It cures astonishingly fast.It produces a result that can be cut/shaped with a knife or sanded.And I feel that the paper fiber adds strength.

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  • How to Bend PVC & Make Incredible Shapes

    I'd be cautious about using this technique for actual "pressurized water plumbing".As you can see from the pictures, sand gets trapped in the plastic - which may come out and clog your fixtures.More importantly, there will be some "thin" spots in the tubing after bending which might compromise the integritiy of the pipe for pressurized water.

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  • Make Straight Cable Into Coiled / Pigtail Cable

    Interesting "twist"!The cable isn't "waterproof", so some water IS going to get in. I bet that it WILL cause problems over time.Can you put the whole mess (rod, cable etc) in a ziplock bag with most of the air pressed out before submerging it?

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  • Soldering Clean Wire Splices

    Ditto on the RTV.Just don't use "GE Silicone 1" or any other silicone that smells like vinegar.The acetic acid (vinegar smell) fumes emitted during curing will eat/corrode your wire badly.

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  • RicksterInstructables commented on Technopolis STREAM's instructable Magnetic Fluid1 year ago
    Magnetic Fluid

    Doesn't "plant based" oil go rancid eventually?

    Any chance you can post a link to an English explanation of how this works?What makes the "spiky"?Rather than just attraction (like "ferro putty" I have).

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  • 3 Beginner Arduino Mistakes

    Ah yes, and the compiler doesn't always warn you of such mistakesif (x = y)Is way different thanif (x == y)If you use "if (x = y)" by mistake, instead of comparing x to y, it assigns the value of y to x and returns true based on the value of x - after setting it to y (or maybe it returns y, I can't remember, which is a good reason not to do this on purpose.The reason the compiler doesn't give you an error is that it's perfectly valid syntactically. And there are actually cases where you might want to do it (I never do it. It's confusing.)

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  • How to Properly Clean a Mechanical Keyboard

    that "goop" sold for cleaning stuff actually works well on keyboards.You kind of roll it around and mush it into corners and it removes the dust/gunk.

    That "goop" sold for cleaning stuff actually works well on keyboards.It's kind of like "slime" and comes in a ziplock bag. Lasts forever.You kind of roll it around and mush it into corners and it removes the dust/gunk.

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  • How to Make Your Own Sugru Substitute

    Cool, good info.

    Just to see what would happen, I added some baking soda (~50% by volume) to some notSugru.I was wondering if you could "neutralize" the acetic acid.But I figured it wasn't there if it didn't need to be, and I was right.It made an interesting mess.The caulk got thinner in viscosity, turned a milky white.But it didn't even think about curing.Even after a week, it was still the things he gloppy mess.

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  • DIY Variable Power Supply With Adjustable Voltage and Current

    I think the switching regulator he chose is a much better solution than an LM317 linear solution.In addition to a plethora of other reasons, it won't get hot like the LM317 would.

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  • Spiral Staircase With a TON of Curves

    Beyond stunning.Way beyond...

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  • RicksterInstructables commented on 陳亮's instructable Portable WiFi Analyzer1 year ago
    Portable WiFi Analyzer

    would it be code compatible?

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  • How to Deodorize Your Vehicle's Interior

    The small side vents defrost/defog the lower front portion of the side windows - that you look through to see the side view mirrors.

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  • RicksterInstructables commented on revithaca's instructable Hello There Boxes1 year ago
    Hello There Boxes

    Cool project. I just may buy a photon!

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  • RicksterInstructables commented on zaphodd42's instructable Make PVC Look Like Wood1 year ago
    Make PVC Look Like Wood

    FRKS1904 -WOW!This could not look more AWESOME!

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  • How to Make Your Own Sugru Substitute

    When trying to coat/encase electronics with silicone caulk, I have had problems with the acetic acid (I assume) severely corroding the copper and other metal (ends up looking like a leaked battery). Any suggestions?

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  • Metal Etching - How to Make a Man's Visiting Card

    Who's a chemist?As a last step, could you switch the container "cathode" to some other material and then change the power supply direction - to "plate" your card?For instance, I imagine you could use a piece of unused PCB material to copper plate it?And you could do it before or after removing the toner - depending on the look you want (the whole card plated, or only where there is no "ink").Granted copper plate might not be a good look (it tarnishes badly/quickly) but maybe another metal is readily available that would work? Like that $1000 gold coin you have :)

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  • RicksterInstructables commented on mikeasaurus's instructable Fix a Hole in Drywall2 years ago
    Fix a Hole in Drywall

    Now, that's a great idea! Keeps you from having to blend the second thickness if paper.

    Nice idea.Only thing I'd add:The way you have shown (dry plug pushed into hole), I doubt it has any significant bond between the plug and hole and is relying on the paper alone (I don't think the mud in the hole is going to stick to the dry dusty edge of the plug).If you moisten the the gypsum edges of both the hole and patch plug and rub (by finger or whatever) some mud into the gypsum, you'll get a better bond of the patch plug to the hole.It's (almost) always better to put any type of "adhesive" on both surfaces before "bonding".

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  • RicksterInstructables commented on aridbennett's instructable Self Spinning Gyroscope2 years ago
    Self Spinning Gyroscope

    Do I need retraining in gyroscopes?In the "video" at the very top of the Instructables - Why does spinning the base cause the gyro to flip?

    Beautiful! Unfortunately, wayyyy beyond my "machining" capabilities (drill, hacksaw, file lol).Most people think you need to control the "attraction" of magnets to make a motor, but often it's easier (especially in terms of commutation) to make a motor based on repelling of magnets.Once "tweaked", does the motor/rotor spin either way? If not, I expect you could "tweak" it so it does...A suggestion/question that might help builders -1 - It wasn't clear to me which end (N/S) of the coil do you want near the magnets? I guess it depends which side of the Hall effect is facing the magnets...

    As you say, quite a trick.Any chance you have a link?

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  • 5 Ways to Remove a Stripped Screw

    I think it has grit in it.

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  • Large Bore Vacuum Cannon

    I think they realized that there would be zero chance that they could build it without leaks.And pulling a vacuum in a tube that size of any length would take basically to infinity.The latest plans I saw for the hyperloop had it "relying" on only a "subtle" vacuum.Because Elon Musk is a well respected visionary, I won't tell you what my spell check did to "hyperloop."

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  • WiFi Weather Display With ESP8266

    Very nice, and well explained.How do you get the seven segment display to shine so brightly through black paper?Is it special paper?Does the color of paper/color of led matter?

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  • Mega Torch - the ultimate guide

    Please don't make this your last Instructables based on my comments!!!I was trying to be constructive, and am sincerely sorry if I offended you.You've done cool stuff. Share it. Let others help you improve your designs!That's what Instructables is all about!

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  • Mega Torch - the ultimate guide

    Sure, I'd be happy to backup my claims with facts.The datasheet you show is deceptive in that they plotted X only between min and max Vf. They didn't plot from zero volts. In the small range they plot, the line, though more exponential, appears almost linear, but look how steep it is! Current is VERY sensitive to voltage!I've included a datasheet from a single Cree LED (easier to read than serial strings). They also plotted only over rang of Vf. So I filled in the plot. My red line extends to one volt before running out of paper. Notice forward current is near ZERO and the knee I described is clearly visible.You are playing too close to disaster. You will get burned.If you have any further questions, feel free to ask.

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  • Mega Torch - the ultimate guide

    Incandescent bulbs are resistive - not completely linearly, but relatively so (resistance changes pretty dramatically with temperature - which is good, makes them self current correcting).You observation about "check valves" is an interesting analogy.Ignore reverse voltage for the moment, because most diodes (except Zeners) are intended to be used in forward bias. Mostly.If you look at the voltage vs current plot of a resistor, it will be a straight line. More voltage, proportionately more current. V=I*R.Most semiconductors behave in non-resistive, non-linear V vs C relationships.If you imagine a "check valve" that "sticks", that's kinda like a diode.Nothing flows backwards. But you need some forward pressure to overcome the "sticking" before any ...

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    Incandescent bulbs are resistive - not completely linearly, but relatively so (resistance changes pretty dramatically with temperature - which is good, makes them self current correcting).You observation about "check valves" is an interesting analogy.Ignore reverse voltage for the moment, because most diodes (except Zeners) are intended to be used in forward bias. Mostly.If you look at the voltage vs current plot of a resistor, it will be a straight line. More voltage, proportionately more current. V=I*R.Most semiconductors behave in non-resistive, non-linear V vs C relationships.If you imagine a "check valve" that "sticks", that's kinda like a diode.Nothing flows backwards. But you need some forward pressure to overcome the "sticking" before any current will flow. Then, once the valve opens, it presents almost no resistance and as much water as possible can flow... For diodes, the "sticking point" is called Vf (forward voltage).Instead of a straight V/I plot, diodes have what's called a "knee". Current will be a horizontal line at zero up to this Vf, then the plot will go nearly vertical... With quite a sharp "corner" or knee.For a regular diode, Vf would be about ~0.7V. Red LED ~1.7V, white LED ~3.2V etc.Again, below Vf almost no current flows, the LED will be extremely dim or off. Above Vf (even a little), as much current will flow as your power supply can handle!The LED might be rated at 20mA. Your battery can put out a lot more than that!You need at Vf, but you something to regulate the current to below maximum.This can be done with a simple resistor, or a more complex current regulator. If you connect a 20mA white LED to a 9V battery, you'll probably see a brief flash, and then think you got a defective LED... The 20mA spec says all it can HANDLE is 20mA. At nine Volts, a lot more than 20mA will flow (remember our V/I plot?).In a nutshell, if you want to drive a white 20mA LED from a nine volt battery, subtract Vf from 9V, you get 5.8V left over you need to get rid of, and you want everything balanced at 20mA. If you put 290 ohm resistor in there, at 20mA, it will have our desired 5.8V across it, leaving 3.2V for the LED. But - here's the good part - If more than 20mA starts to flow, the resistor will steal more voltage (V=IR), leaving less for the LED, and vice-versa. Things will balance nicely at the knee at ~3.2V and 20mA.

    That's the second thing about LEDS."Under driving them", below Vf, they do little or nothing.If you're making them light up, you are driving them at Vf.Oh, and as (most) LEDs get hotter, Vf decreases. So if you try to tweak the voltage to get the desired current... As it heats up, Vf goes down, current goes up... Meltdown, slowly dim or last gasp bright flash... Dead.You really MUST understand that LEDs are CURRENT devices and drive them with a constant current source. This needn't be complex - it could be a simple resistor - but it is necessary if you want to make anything other than a flash-bulb.

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  • DIY Mini Bluetooth Speaker (BoombeAt :)

    So is it a common ground that causes a problem, or a common power supply?Which gets noisy? Does the amp push noise back on to the BT supply?Can you just use a bunch of capacitors to quiet things out?

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  • Nixie Watch Prototype_C

    I LOVE it.As one who followed the Apollo program as a kid, I've always lived nixies.And while this is wayyy beyond my capabilities, it inspires me to make something.Thanks for sharing!

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  • Hack a PC Speaker Into a Guitar Amp

    >>2. If both inputs are included... could both inputs play simultaneously? >>Say like a backing track that you could strum over?>>Absolutely.Absolutely - unlikely.You can't just "short" the two inputs together and feed them to the amplifier.You'd need to make some type of "mixer" circuit. This could be as simple as some resistors, or a more complex circuit involving a "summing" amp.

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  • RicksterInstructables commented on mikeasaurus's instructable Restore Old Paper Cutter2 years ago
    Restore Old Paper Cutter

    Fantastic job. And great instructable.Four comments:1: are you at all afraid that glueing the warped side rails in will warp the walnut deck?2: with this type of paper cutter you must be extremely careful with the two blade edges. The one on the handle and the mating edge on the deck. They may not look it, but they are razor sharp. Do not run your fingers down these edges any more than you would a knife blade!3: while cleaning/restoring a cutter, you must be extremely careful not to do anything that will "round" the two cutting edges (right side of deck blade and left side of arm blade). You will ruin it forever. See below for how to remove nicks/sharpen blades.For anyone who wants to restore a quality paper cutter - visit your local elementary school. Back in the corner of th...

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    Fantastic job. And great instructable.Four comments:1: are you at all afraid that glueing the warped side rails in will warp the walnut deck?2: with this type of paper cutter you must be extremely careful with the two blade edges. The one on the handle and the mating edge on the deck. They may not look it, but they are razor sharp. Do not run your fingers down these edges any more than you would a knife blade!3: while cleaning/restoring a cutter, you must be extremely careful not to do anything that will "round" the two cutting edges (right side of deck blade and left side of arm blade). You will ruin it forever. See below for how to remove nicks/sharpen blades.For anyone who wants to restore a quality paper cutter - visit your local elementary school. Back in the corner of the copier room, they will have at least one cutter no one uses. They may welcome your offer to fix it, or offer to give it to you. When teachers cut through staples, it nicks the blades. This causes them to jam and tear paper instead of smoothly cutting it. Nothing frustrates a frazzled teacher more than running off 22 copies of something and then tearing them when they try to trim them. Trust me. My wife is a 28 year veteran second grade teacher. I've tried (often successfully) to refurbish the blades of many cutters they've "junked" because I couldn't stand them throwing these out. Good ones cost multi-hundred dollars.4: with this type of paper cutter you must be VERY careful with the two blade edges. The one on the handle and the mating edge on the deck.-- they are both extremely sharp. And must be for it to work. Do not run your fingers down the edges any more than you would a knife blade!-- you must not do anything (like sanding) that will round the edges at all.-- the only way I have found to sharpen/smooth the action of these:--- remove the nicks (DO NOT really attempt to sharpen. You will ruin it forever).---- making just a few passes with a ceramic (or diamond) knife hone (you will feel it when you hit the nicks and when you've removed them.---- run a ceramic (or diamond) knife hone lightly down the "top" of the metal part of deck. Perfectly flat against surface.---- run hone perfectly vertical along "right" edge of deck plate.---- run hone perfectly flat against left edge of blade.---- run hone down cutting edge of blade, trying your best to match the existing edge angle.

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  • Simple Compact 5v Voltage Regulator with Low Battery Alarm

    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings goin...

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    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going to fail - quickly.First, remember that linear regulators are basically variable resistors. They decrease the voltage - as waste heat. Lots of heat. 3W max, in this case. That doesn't sound like much, but it is when it's coming from a tiny part. I overloaded a linear regulator once enough that the solder melted and it fell off the board!If you look at the specs, you see some interesting things.1 - thermally regulatedIf it overheats, it will "limit" in some way.Maybe decrease output voltage in an attempt to decrease output current.You're not monitoring the output voltage, so we don't know if it's stable at 1A.2 - max junction (silicon) temperature 125dC.3 - thermal impedance of sot23 is 45/90dC/W -> if heat sink tab attached to ground plane.That's the kicker.Thermal impedance is rated in different ways. Junction to case, case to ambient etc.You don't have the heat sink attached to anything. They don't specify junction to ambient w/ no ground plane, but it's certainly MUCH higher than 90dC/W.But for the sake of my explanation, let's assume it's only 100dC/W.Let's say we're in free air, 25dC, no foam etc. We've got over 3W of heat going on. Work backwards. 25 + (3 * 100) is 325dC...The case is going to be REALLY hot, but the silicon inside is going to be VERY ANGRILY hot.So, how would you make this work?1 - today, you can design it as a " quiet" switcher.2 - Use a TO-3 package. They have much better case/ambient impedance.3 - use an etched board with a large, unbroken copper area that the heat sink tab is soldered to. The copper will radiate the heat. Note this still may not be enough!4 - here's what I would consider.You know you're only going to let the batteries go down to ~7V.Dropout voltage of ams117 is 1.3V, so you only need ~6.3V going into it.Between you're battery sense point, and the regulator input add a 1A, 1W (or 2W) diode (regular, not shot toy). That adds a 0.7V drop and wastes almost 1W of your 3W outside the ams117.

    I'm No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it. You need to make sure your design is valid under all conditions, against worst case vendor specs. 5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers! My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly. And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load. If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% someth...

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    I'm No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it. You need to make sure your design is valid under all conditions, against worst case vendor specs. 5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers! My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly. And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load. If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going to fail - quickly. First, remember that linear regulators are basically variable resistors. They decrease the voltage - as waste heat. Lots of heat. 3W max, in this case. That doesn't sound like much, but it is when it's coming from a tiny part. I overloaded a linear regulator once enough that the solder melted and it fell off the board! If you look at the specs, you see some interesting things. 1 - thermally regulated If it overheats, it will "limit" in some way. Maybe decrease output voltage in an attempt to decrease output current. You're not monitoring the output voltage, so we don't know if it's stable at 1A. 2 - max junction (silicon) temperature 125dC. 3 - thermal impedance of sot23 is 45/90dC/W -> if heat sink tab attached to ground plane. That's the kicker. Thermal impedance is rated in different ways. Junction to case, case to ambient etc. You don't have the heat sink attached to anything. They don't specify junction to ambient w/ no ground plane, but it's certainly MUCH higher than 90dC/W. But for the sake of my explanation, let's assume it's only 100dC/W. Let's say we're in free air, 25dC, no foam etc. We've got over 3W of heat going on. Work backwards. 25 + (3 * 100) is 325dC... The case is going to be REALLY hot, but the silicon inside is going to be VERY ANGRILY hot. So, how would you make this work? 1 - today, you can design it as a " quiet" switcher. 2 - Use a TO-3 package. They have much better case/ambient impedance. 3 - use an etched board with a large, unbroken copper area that the heat sink tab is soldered to. The copper will radiate the heat. Note this still may not be enough! 4 - here's what I would consider. You know you're only going to let the batteries go down to ~7V. Dropout voltage of ams117 is 1.3V, so you only need ~6.3V going into it. Between you're battery sense point, and the regulator input add a 1A, 1W (or 2W) diode (regular, not shot toy). That adds a 0.7V drop and wastes almost 1W of your 3W outside the ams117.

    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings goin...

    see more »

    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going to fail - quickly.First, remember that linear regulators are basically variable resistors. They decrease the voltage - as waste heat. Lots of heat. 3W max, in this case. That doesn't sound like much, but it is when it's coming from a tiny part. I overloaded a linear regulator once enough that the solder melted and it fell off the board!If you look at the specs, you see some interesting things.1 - thermally regulatedIf it overheats, it will "limit" in some way.Maybe decrease output voltage in an attempt to decrease output current.You're not monitoring the output voltage, so we don't know if it's stable at 1A.2 - max junction (silicon) temperature 125dC.3 - thermal impedance of sot23 is 45/90dC/W -> if heat sink tab attached to ground plane.That's the kicker.Thermal impedance is rated in different ways. Junction to case, case to ambient etc.You don't have the heat sink attached to anything. They don't specify junction to ambient w/ no ground plane, but it's certainly MUCH higher than 90dC/W.But for the sake of my explanation, let's assume it's only 100dC/W.Let's say we're in free air, 25dC, no foam etc. We've got over 3W of heat going on. Work backwards. 25 + (3 * 100) is 325dC...The case is going to be REALLY hot, but the silicon inside is going to be VERY ANGRILY hot.So, how would you make this work?1 - today, you can design it as a " quiet" switcher.2 - Use a TO-3 package. They have much better case/ambient impedance.3 - use an etched board with a large, unbroken copper area that the heat sink tab is soldered to. The copper will radiate the heat. Note this still may not be enough!4 - here's what I would consider.You know you're only going to let the batteries go down to ~7V.Dropout voltage of ams117 is 1.3V, so you only need ~6.3V going into it.Between you're battery sense point, and the regulator input add a 1A, 1W (or 2W) diode (regular, not shot toy). That adds a 0.7V drop and wastes almost 1W of your 3W outside the ams117.

    Nice project. Really compact.Not to be a party pooper, but...8.4V - 5V = 3.4V.3.4V * 1A = 3.4WI don't think there is any possibility that your ASM117 sot223 (with the heat sink pin touching, but not soldered to only one, single sided copper pad), would ever be capable of dissipating that kind of heat...(The datasheet says 45-90 degC/W depending on ground plane, of which you have virtually none).Have you tested it at 8.4V/1A for any significant time? Did the AMS117 shutdown/melt (seriously).If nothing else, consider soldering a piece of the largest gauge solid copper wire that will fit through the he holes in your perfboard and "weaving" it up/down through the four vacant holes in front of the heat sink. That'll give you something.Now try to draw an amp. Might work. The wire wi...

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    Nice project. Really compact.Not to be a party pooper, but...8.4V - 5V = 3.4V.3.4V * 1A = 3.4WI don't think there is any possibility that your ASM117 sot223 (with the heat sink pin touching, but not soldered to only one, single sided copper pad), would ever be capable of dissipating that kind of heat...(The datasheet says 45-90 degC/W depending on ground plane, of which you have virtually none).Have you tested it at 8.4V/1A for any significant time? Did the AMS117 shutdown/melt (seriously).If nothing else, consider soldering a piece of the largest gauge solid copper wire that will fit through the he holes in your perfboard and "weaving" it up/down through the four vacant holes in front of the heat sink. That'll give you something.Now try to draw an amp. Might work. The wire will get warm!

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  • Electromagnetic levitation device

    You need feedback.What you're describing might work for a moment, but only a moment.If the magnet gets a tiny bit too far away, it falls. A tiny bit too close - click - it's stuck to the nail.Your technique is like controlling the heat in your house by timing the furnace on/off cycle times. It would work for a moment.As soon as the outdoor temperature changes, the wind changes, the sun comes out, someone comes in the front door etc....... Things collapse.You can see that in almost any control system, you need feedback - in the furnace case, the thermostat has a thermometer that provides that feedback.A sophisticated heating system might cut back on the heat as you approached the target so it wouldn't overshoot. Your car's cruise control doesn't "floor it" when you're below tar...

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    You need feedback.What you're describing might work for a moment, but only a moment.If the magnet gets a tiny bit too far away, it falls. A tiny bit too close - click - it's stuck to the nail.Your technique is like controlling the heat in your house by timing the furnace on/off cycle times. It would work for a moment.As soon as the outdoor temperature changes, the wind changes, the sun comes out, someone comes in the front door etc....... Things collapse.You can see that in almost any control system, you need feedback - in the furnace case, the thermostat has a thermometer that provides that feedback.A sophisticated heating system might cut back on the heat as you approached the target so it wouldn't overshoot. Your car's cruise control doesn't "floor it" when you're below target speed, then drop the throttle to zero when you hit target - treating your throttle like the furnace on/off switch. That would be a rough ride!Look up "PID controllers". Proportional/Integral/DerivativeFor your car's cruise control:Basically, we're way under target speed? Floor it. As we approach target, start to ease off.The further from target, the more it pushes the throttle (P=proportional).How quickly are we approaching the target (I=integral, D=derivative) - how quickly/how much do we ease off.If we do it right, we'll end up with the throttle right where it needs to be to maintain target speed.

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  • RicksterInstructables commented on ShakeTheFuture's instructable Make a Melting Spoon2 years ago
    Make a Melting Spoon

    1 - Did you use any type of mold release between the two silicone pours? I would have thought the two would be permanently bonded together!Just to help cost it out:2 - How much silicone did you use?3 - How much gallium did you use?I bought some "desoldering solder" - you use it by heating a joint you want to desolder (usually all the pins of a chip), then heating them and lifting the chip off.The desolder game solder gas a much lower melting point than normal tin/lead solder, so it makes it much easier (even after the solders mix). The lower melting point is easier on the chip, and it stays melted much longer allowing you to get the part off.Regular "eutectic" tin/lead solder (eutectic=lowest melting point is about 63% tin, 37% lead) melting point is 361F).The stuff ...

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    1 - Did you use any type of mold release between the two silicone pours? I would have thought the two would be permanently bonded together!Just to help cost it out:2 - How much silicone did you use?3 - How much gallium did you use?I bought some "desoldering solder" - you use it by heating a joint you want to desolder (usually all the pins of a chip), then heating them and lifting the chip off.The desolder game solder gas a much lower melting point than normal tin/lead solder, so it makes it much easier (even after the solders mix). The lower melting point is easier on the chip, and it stays melted much longer allowing you to get the part off.Regular "eutectic" tin/lead solder (eutectic=lowest melting point is about 63% tin, 37% lead) melting point is 361F).The stuff I bought was marked something like 132 degrees F. I thought it must be a typo and it should be degrees C. But, low and behold, I boiled some water and the stuff melted!! In hot water!! It must be gallium.

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  • RicksterInstructables commented on How-ToDo's instructable Powerful burning Laser2 years ago
    Powerful burning Laser

    Naive question.Is this focused to "burn" at a specific distance (matches, tape etc.), or is the "full" beam powerful enough to burn "anywhere" along it's length (sounds dangerous)?I mean where would you point it to test it that it wouldn't cause damage... Oops. Burned a hole in the wall...

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  • DC Motors-Part 1/3: Continuous, Gear, Servo, Brushless and Coreless, Vibration, and Stepper, A Tutorial

    gddee Some good questions.Yes, when current in an inductor of any kind, including a motor winding, is shut off, the collapsing magnetic field - and the fundamental nature of an inductor - tries to keep the current flowing. On a inductor in a relay, for example, you use a "fold back", "fly back" diode which are just plain reverse polarized diodes in parallel with the coil. They allow the coil current to continue - by circulating back to the beginning - until it dissipates.Without this, the inductor really wants that current to keep flowing. It will create lots of volts in an effort to push those amps. The magnitude of the voltage, and the fact that it is reversed, will blow apart many semiconductor driver circuits without diodes.As an aside, the "points" in ...

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    gddee Some good questions.Yes, when current in an inductor of any kind, including a motor winding, is shut off, the collapsing magnetic field - and the fundamental nature of an inductor - tries to keep the current flowing. On a inductor in a relay, for example, you use a "fold back", "fly back" diode which are just plain reverse polarized diodes in parallel with the coil. They allow the coil current to continue - by circulating back to the beginning - until it dissipates.Without this, the inductor really wants that current to keep flowing. It will create lots of volts in an effort to push those amps. The magnitude of the voltage, and the fact that it is reversed, will blow apart many semiconductor driver circuits without diodes.As an aside, the "points" in an older ignition coil car were basically a switch that pulsed current in the primary of the coil, inducing a much higher pulse out the secondary. Contrary to what most think, the spark didn't happen when the points closed - but when they opened! It takes a while for the current to build up, but you can stop it on a dime. How did they keep the points from arcing and burning up? A diode would have defeated the purpose - we want to stop the current abruptly. Instead, they added a small capacitor (called a condenser). As the points started to open, the cap would charge. By the time of he cap was fully charged, the points were open far enough a spark couldn't gap across them!Ok, back to the DC motor "snubber".Things are bade much more confusing by the armature and brushes. While the voltage is always going one way into the motor, the voltage across each coil is constantly switching as it attracts, then repels each magnet in turn. You can't put a snubber on the coils, they are kinda "AC". You can't really reclaim any energy, because the magnetic flux is caused by a change in current. When it's going one way, and you switch it to the other, you've changed it by twice as much - you haven't really wasted anything.Now from the outside of the DC motor: the commutator, brushes, and multiple coins conspire to make it look like an inductor. But worse. The coasting of motor actually makes look like a bigger inductor, because it's a generator! So if we abruptly cut off the power, the inductance will create a bad voltage, and the continued in rotation of the motor will generate more bad voltage.A diode gets rid of the bad voltage in the same way as a conventional inductor.I've always thought it should put a huge load (line a short circuit) on the generator, and stop it quickly, but this doesn't happen. And good thing, or PWM motor control wouldn't work. Can someone explain why the diode doesn't load the "generator"?Fun thing to try with a brushless motor. Hold the leads apart. Spin it with your hand. Short any two leads together. Try to turn it by handAgain, why does shorting the leads of a brushed motor not cause this??

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  • RicksterInstructables commented on surmit chauhan's instructable DIY Camera Microscope2 years ago
    DIY Camera Microscope

    No.It would burn out the LED almost immediately.When powering LEDs you need to limit the current going through them. This is most often done using current limiting resistors.In the case of a white LED (forward voltage 3.2V), 20mA you would need about 300 ohms.This can be calculated by (9 - 3.2) / 0.020 = 290(As always V = I * R, so V / I = R)

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  • Modify a cheap USB charger to feed an iPod, iPhone or Samsung Galaxy

    You tested this? Charging at 6.5V? Ballsy. I hope it wasn't "your" phone...RE: boost charging an almost full battery. Most "experts" (and I say that because they don't all agree) claim that when a LiPo is approaching full, you should.- dramatically taper off current- pulse chargeBesides it not being recommended, I think you'd find that a 5V source would have trouble pushing a substantial current into an almost full LiPo. As it approaches full (4.2V) you need to be feeding it 4.3V to get any current to flow. I don't know what voltage you'd need to get, say 1.0A to flow. 0.6V of headroom doesn't leave much for supervisory/regulatory circuitry.I suspect the other reason is that while you're punching current into an almost full LiPo, it's very hard to monitor its real &q...

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    You tested this? Charging at 6.5V? Ballsy. I hope it wasn't "your" phone...RE: boost charging an almost full battery. Most "experts" (and I say that because they don't all agree) claim that when a LiPo is approaching full, you should.- dramatically taper off current- pulse chargeBesides it not being recommended, I think you'd find that a 5V source would have trouble pushing a substantial current into an almost full LiPo. As it approaches full (4.2V) you need to be feeding it 4.3V to get any current to flow. I don't know what voltage you'd need to get, say 1.0A to flow. 0.6V of headroom doesn't leave much for supervisory/regulatory circuitry.I suspect the other reason is that while you're punching current into an almost full LiPo, it's very hard to monitor its real "fullness" even if you pulse charge (you'd have to load it between pulses to get an accurate read).The dangers of overcharging (bloating/fire) are just too high.

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  • RicksterInstructables commented on YuKonstruct's instructable Simple Homopolar Motor2 years ago
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