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  • DIY Mini UPS for WiFi Router / Modem

    I think you are out-of-spec for both a router battery and, definitely, for a UPS.The specification for your items are:- Battery: 3.7V, 4.8A current max- 12V step up: max 2A- Lithium battery charger: 1AIf you want to use the 12V output only, the router you have has a 12V 1A input. This means that the current required from the battery is 12V*1A/3.7V = 3.2A. The battery can sustain that, but I'm not sure about the boost (the maximum output current of 2A is probably at very low voltages, not at 3x the input voltage). Probably the 1A current for the router is the absolute maximum one, but some more calculations are needed. For sure you can't charge your mobile while the router is powered...Regarding the UPS usage, so using it while it is plugged in, the charger output of 1A will never be abl...

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    I think you are out-of-spec for both a router battery and, definitely, for a UPS.The specification for your items are:- Battery: 3.7V, 4.8A current max- 12V step up: max 2A- Lithium battery charger: 1AIf you want to use the 12V output only, the router you have has a 12V 1A input. This means that the current required from the battery is 12V*1A/3.7V = 3.2A. The battery can sustain that, but I'm not sure about the boost (the maximum output current of 2A is probably at very low voltages, not at 3x the input voltage). Probably the 1A current for the router is the absolute maximum one, but some more calculations are needed. For sure you can't charge your mobile while the router is powered...Regarding the UPS usage, so using it while it is plugged in, the charger output of 1A will never be able to sustain the 3.2A current required. For this reason, you can't use it as a usual UPS.

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  • frarugi87 commented on TheTNR's instructable VORONOI HEART LAMP7 weeks ago
    VORONOI HEART LAMP

    What is the purpose of step 8? Is it to have a clear finish without having to use finer and finer sandpaper?For clarity, moreover, I'd invert steps 4 (Making epoxy) and 5 (Assemble Voronoi Heart and Led), since you have a limited time to pour the epoxy (and so it is better to have the heart already assembled before mixing the epoxy)

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  • frarugi87 commented on DiggingFox's instructable Resistor Organizer2 months ago
    Resistor Organizer

    I did something similar, but with 1.5ml test tubes (for SMD resistors).One thing I suggest you is to organise them in rows of 12 elements. Why? Because the resistors values are arranged in the E12 or E24 values range; the E12 is 12 values in a decade, so if you organise them in 12 elements rows you will have them sorted properly. If you have an E24 series you will have two rows occupied by one series, and then this will start again.In my setup I use some 72-holes containers (6 rows 12 columns), and I managed to store three decades of E24 resistors in a single box; consequently I have a 1-910 ohm box, a 1k-910k box and a >1M box (ok, this is not full, so I also have other values in this one).

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  • frarugi87 commented on Random_Canadian's instructable Secret Dual USB Data Vault2 months ago
    Secret Dual USB Data Vault

    To reduce the complexity you could have wired only the D+, D-, GND and VCC wires. You would have lost the USB3 speed on the second drive, but... who needs it on a 32GB drive?Regarding the project, instead of a relay (which is large) you could have used just two MOSFETsFor the rest, good idea and good execution :)

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  • frarugi87 commented on Alex in NZ's instructable Hide Your Flash Drive in Plain Sight2 months ago
    Hide Your Flash Drive in Plain Sight

    You can also make the drive inside the cable more secure through some SW like VeraCrypt. I never used it, but it was my top choice when I was researching ways to hide personal information on USB drives.

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  • frarugi87 commented on JonMackey's instructable Dust Collector Full Detector2 months ago
    Dust Collector Full Detector

    Isn't it a bit risky to set the 5V DC-DC voltage AFTER mounting? this way if the screw is turned all the way to the 12V it will fry. It's better to set it before mounting, or at least turn the screw all the way to the 0V and then slowly increase while monitoring. Or the best solution IMHO: include a series element (a resettable fuse, a 0 ohm resistor, ...) that you do not mount at first, then set the voltage to 5V, then mount it as a last step to power the rest of the board

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  • frarugi87 commented on dkassman's instructable Easily Soundproof a Stainless Steel Sink3 months ago
    Easily Soundproof a Stainless Steel Sink

    Sometimes you just don't have any choice... Just like when me and my GF were searching for an apartment and the two-bowl sink was a must... FYI, one bowl for dirt dishes, one for soapy ones.

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  • frarugi87 commented on MelnEdgars's instructable 5$ PCB CALENDAR WITH BINARY CLOCK3 months ago
    5$ PCB CALENDAR WITH BINARY CLOCK

    Yeah, we'll try that as soon as we got some time to tinker with it. Thank you :)

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  • frarugi87 commented on MelnEdgars's instructable 5$ PCB CALENDAR WITH BINARY CLOCK3 months ago
    5$ PCB CALENDAR WITH BINARY CLOCK

    Yes, it works thanks :)Just a couple of things:1) there are some 10 ohm resistors; are they really 10 ohm or they are 10k?2) the images of the schematic are not very clear; maybe it is better to include the full resolution ones too as attachment (or, better, the schematic as a pdf)3) from the pictures it seems to me that the years print is 2019,2020,2021,2022,2021 (and not 2023). Is this a mistake?4) maybe it would have been easier to use the so-called charlieplexing technique rather than a full matrix, to save pins and componentsThank you for your project :)

    The BOM file cannot be downloaded; is it just me or it happens to other too?

    Thank you for your help ;)Just another question, since I'm not so much proficient with eagle: you can't modify the layout from the gerber only, can you? I wanted to learn something by slightly modifying your design (for instance switching PC4 and PC5 with PD0 and PD1 , so that I2C is accessible - for an RTC if needed) but without starting from scratch. Is it possible?

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  • frarugi87 commented on Andrew_Kirkwood's instructable Deck of Cards Safe3 months ago
    Deck of Cards Safe

    If you flip the cards deck, thus leaving the bent card on the bottom (or better, glue the bottom card rather than the top one), you would have had a much nicer effect IMHO

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  • frarugi87 commented on videoschmideo's instructable Make Circuit Boards With Lasers3 months ago
    Make Circuit Boards With Lasers

    What about repeating the steps to apply a solder mask at the end?

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  • frarugi87 commented on TechKiwiGadgets's instructable LED 3D Printer Bed Leveling Tool3 months ago
    LED 3D Printer Bed Leveling Tool

    Another Cobblebot "proud" owner? :P

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  • Tutorial for TTP223 Touch Sensor Module ( Capacitive)

    Reading the datasheet, the sensitivity can be decreased bya) reduce the size of the sensor (which you cannot do)b) increase the distance (for instance put some plastic above the contact)c) add a capacitor between the sensor and ground.If you can't do solution b, then I suggest you to add a capacitor. I do not have these modules, but if I saw correctly the unpopulated pads in the top right corner of the board images are for this purpose. Just solder there a small SMD capacitor (10-50pF, in a 0603 or package I think, or a 0805) and the sensitivity should decrease. The larger the capacitor, the smaller the sensitivity (but do not go beyond 50pF)

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  • frarugi87 commented on Rob Cai's instructable Arduino Basic PC With VGA Output4 months ago
    Arduino Basic PC With VGA Output

    You will need a USB host controller, like for instance this:https://store.arduino.cc/arduino-usb-host-shield

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  • frarugi87 commented on Eric Brouwer's instructable LAN/Network Monitor4 months ago
    LAN/Network Monitor

    I'm not sure whether the app you mentioned just scans once or continuously. In any case, I think this is designed to be on 24/7 and to consume very little power, while a Mac consumes, well, a bit more ;)

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  • frarugi87 commented on appideas's instructable WiFi LED Light Strip Controller5 months ago
    WiFi LED Light Strip Controller

    Good project :)Just one note: usually you should put a small resistor (usually around 200 ohm) between the microcontroller pin and the gate of the MOSFET; this is used to limit the current at the very beginning of the turn on. This is especially true when using high power MOSFETs and PWM modulation, and you use both in your application. Moreover I prefer to also put a pull-up (pMOS) or pull-down (nMOS) resistor directly on the gate to ensure power down when the microcontroller is booting

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  • frarugi87 commented on osgeld's instructable Put Your SMD Parts on Standard Perfboard5 months ago
    Put Your SMD Parts on Standard Perfboard

    You are totally mad :D

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  • frarugi87 commented on PCaron4's instructable Halloween Standing Mummy Prop6 months ago
    Halloween Standing Mummy Prop

    "I think I will have to wrap my husband the next time" This sounds scary... You are going to take him out of there, aren't you?

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  • frarugi87 commented on Mad Gyver's instructable DIY Time Control Machine8 months ago
    DIY Time Control Machine

    Personally I think that 50W should be enough (I'll use a 50W myself). As for the dissipator, I think you are a bit confused. First of all the voltage is not 12V, but 34. Then this is a stroboscope, not a LED lamp. This means that it gets turned on for a very brief moment. Looking at the code, the LED gets turned on for 200us every cycle, and the cycle lasts from 2200us to I think 6624us. In the worst case, which is 2200, estimating a LED efficiency of 20% (which is very poor) the power dissipated by the LED is roughly 100W * 80% * 200/2200 = 7W. Will a copper heatsink be enough? I don't know, but I'm positive about this. And in any case if you feel it heating in your hand you can shut it down ;)

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  • frarugi87 commented on Nematic!'s instructable DIY Li-ion Capacity Tester !8 months ago
    DIY Li-ion Capacity Tester !

    I have a few comments/questions:- What is the point when measuring the voltage on the node between transistor and resistor? The Rds-on of the MOS is around 30mOhm, and with a current of roughly 0.5A this means a 15mV drop. Or a 0.3% of precision loss. Totally negligible- What is the purpose of the resistive dividers (R1-R3 and R2-R4) to measure the voltage? Your max voltage is 4.3V, and you are not usign the internal voltage reference, so the max voltage you can measure is 5V. Why are you dividing it in half?- Speaking of voltage references, are you sure that the 5V are stable? Even with the OLED? Personally I'd use the internal reference (and then you really need the R1-R3 voltage divider, but the resistors values should change) - You shouldn't drive a MOSFET that way; you should add a...

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    I have a few comments/questions:- What is the point when measuring the voltage on the node between transistor and resistor? The Rds-on of the MOS is around 30mOhm, and with a current of roughly 0.5A this means a 15mV drop. Or a 0.3% of precision loss. Totally negligible- What is the purpose of the resistive dividers (R1-R3 and R2-R4) to measure the voltage? Your max voltage is 4.3V, and you are not usign the internal voltage reference, so the max voltage you can measure is 5V. Why are you dividing it in half?- Speaking of voltage references, are you sure that the 5V are stable? Even with the OLED? Personally I'd use the internal reference (and then you really need the R1-R3 voltage divider, but the resistors values should change) - You shouldn't drive a MOSFET that way; you should add a resistor in series (e.g. 220 Ohm) to limit the current peak at power on/off- Are you sure you can power the buzzer directly? (I couldn't find the data; what is the current it should get at 5V?)Thank you for sharing anyway :)

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  • frarugi87 commented on TimmyL11's instructable Homemade Game Console- "NinTIMdo RP"10 months ago
    Homemade Game Console- "NinTIMdo RP"

    I could not understand the power button circuit. How is it supposed to work? If the switch is not momentary, if I understood it correctly when it is open the PI is not powered, while when it is closed the PI power is removed. If this is the case, I would have wired it in the opposite way; in your way, when the board is turned off the 10k resistor generates a 500uA current, which is low but slowly drains the battery...

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  • frarugi87 commented on badarsworkshop's instructable Bench Power Supply11 months ago
    Bench Power Supply

    In step 5's picture you are putting your fingers around the cables, since you have to rotate the encoder with your right hand and there are the cables in between. Maybe having them under the display (in the non-45-tilted area) would have been a better choice, wouldn't it?

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  • frarugi87 commented on zaphodd42's instructable Make PVC Look Like Wood1 year ago
    Make PVC Look Like Wood

    This is awesome! Good work!

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  • frarugi87 commented on mikeasaurus's instructable QR Coasters1 year ago
    QR Coasters

    Maybe you can also pour some transparent resin on it, in order to have a flat surface and maybe a better look ;)

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  • POV Globe 24bit True Color and Simple HW

    Maybe you have already answered this, but.. Why did you put the buck converter before the bearings? I'd have put it after (i.e. on the moving part); this way the voltage on the bearings is not important, can be noisy, and moreover you regulate it after the bearings, so the current on the bearings is also lower

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  • frarugi87 commented on Jake_Makes's instructable Most REDNECK Forge Ever. Period.1 year ago
    Most REDNECK Forge Ever. Period.

    This is a very cool project... or hot... ;)In any case, when you are done you simply turn on the tap to shut the forge off, don't you? XD

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  • frarugi87 commented on Easy Composites's instructable Resin Penny Floor Project!1 year ago
    Resin Penny Floor Project!

    How does the resin "blend" with other resin? I mean, if I apply another batch of resin, will I see the seam? Both when curing (i.e. in a few minutes/hours from first application of resin) or after some time (e.g. one year after, to cure scratches for instance)

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  • frarugi87 commented on Ameer Tamoor Khan's instructable Soft Muscle (Actuator)1 year ago
    Soft Muscle (Actuator)

    I would have appreciated more the photos of the steps, rather than the photos of the "ingredients" and then a single step telling "mix everything and you are done"

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  • How to Create a Realistic 'Bleeding-Knife' Effect

    Just came here today and... This is horrible............ Really horrible :P

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  • 3D Printing a Curved Shell for a Teapot Handle

    If it becomes "too hot to hold", doesn't it soften also the PLA?

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  • frarugi87 commented on khinds10's instructable Magic Mirror1 year ago
    Magic Mirror

    What do you use on the tablets? I mean, do you manually open the browser? or you have some automated script or app that opens and browses to the correct website?

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  • frarugi87 commented on seanhodgins's instructable Arduino Neural Network Robot1 year ago
    Arduino Neural Network Robot

    If you look at the code you'll find two basic functions, one for training a neural network and the other to execute the calculated values. Personally I've always preferred to train the NN on a PC and to just execute it on the embedded micro, but I think the author wants this to be an educational project.BTW the neural network he is using is called Multi-layer perceptron (MLP), and is one of the "historical" neural networks

    Can you further explain it? Cause I opened the code and inside there is actually a neural network, a classical MLP implementation which tries to avoid the light...

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  • frarugi87 commented on akshay.gupta.904108's instructable Filament Dehumidifier1 year ago
    Filament Dehumidifier

    HelloI see that there are a few things missing from the code, so I'm asking them here. Basically the control of the system is1) if the temperature is less than 45°C, turn on the heater and circulate the air with the fan2) if the humidity is greater than 30%, circulate the air with the fan (and the silica dessicant will de-humidify it)Is this correct?

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  • frarugi87 commented on duncancurry's instructable Low Cost Radar Speed Sign1 year ago
    Low Cost Radar Speed Sign

    Maybe I did not explain myself enough for q1 ;) I read that the Vih was too high, so at least one stage was required. That's why I suggested you to invert the rPI output (and keep the transistor); the nMOS turns on with the 3.3V pulse from the rPI, and so you get a 5V output on the other side.Note, however, that if you want to power the inverters at 5V you'll need the LS family, not the HCT.As for the dual power supply, I think that if you want to properly isolate everything you'd better keep separate grounds too (and use opto-isolators on the data lines). This will also solve your level-adapting issue ;)

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  • frarugi87 commented on duncancurry's instructable Low Cost Radar Speed Sign1 year ago
    Low Cost Radar Speed Sign

    There are some inefficiencies:1) why did you put the inverters too? You just need to invert the signal outputted by the rPI. Or, if you prefer not to invert it, use a 74LS04 hex inverter (TTL levels) and use two inverters in series (you have 6, so you can convert all the 3 channels). A 5V powered TTL port accepts voltages as low as 2V for the high value, so even 3.3V logic is ok for them.2) why didn't you use the 5V from the HDD cable to power the rPI? you can easily avoid another cable coming out of the box....

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  • ASPIR: Full-Size 3D-Printed Humanoid Robot

    First of all, this is impressive... O_OI just have a couple of questions, because here you showed a list of steps to assemble it, but there are a lot of unanswered mechanical, electrical, electronical and informatics questions (of course you could not write here a massive amount of steps, this instructable is already long on its own) ;)Mechanics: what are those springs under the shoulder? Why are they needed?Electric: this robot is a wired one, right? I mean, the power supply comes from the mains. Why did you use two power supplies?Electronic/informatic: so on the robot you have one arduino and one mobile phone. Are they linked (I mean, the mobile is used for "high level" control and the arduino for the "low level", i.e. the direct control of the servos) or the mobil...

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    First of all, this is impressive... O_OI just have a couple of questions, because here you showed a list of steps to assemble it, but there are a lot of unanswered mechanical, electrical, electronical and informatics questions (of course you could not write here a massive amount of steps, this instructable is already long on its own) ;)Mechanics: what are those springs under the shoulder? Why are they needed?Electric: this robot is a wired one, right? I mean, the power supply comes from the mains. Why did you use two power supplies?Electronic/informatic: so on the robot you have one arduino and one mobile phone. Are they linked (I mean, the mobile is used for "high level" control and the arduino for the "low level", i.e. the direct control of the servos) or the mobile is only used for displaying the face and the high level control is done through an external PC or something else?Mechatronic: what are its (or his/her, I don't want to offend if he/she is already sentient) capabilities? Optical recognition through the webcam, interaction, grabbing objects, walking, ...? Did you already program he/she/it or this is "just" the mechanical part (note the "just".. I feel a bit silly by referring to this work with a "just").And... Thank you for sharing. You really made this look very simple :)

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  • TTDS (Traffic Ticket Detection System )

    Is this just an advertisement of your service or an instructable? If it is an instructable, can you explain how it works?

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  • frarugi87 commented on The Sam D's instructable Build an in Ground Swimming Pool1 year ago
    Build an in Ground Swimming Pool

    You are totally mad... This is impressive!Just one note: what if someone who can't swim follows the whole instructable and then at the end reads the last step? XD

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  • frarugi87 commented on mr electro's instructable Fixing a Laptop Adapter1 year ago
    Fixing a Laptop Adapter

    I'd point out that teh capacitors are "bulky", which means they are gone (the top side must be flat for the capacitor to be ok).Moreover when dealing with this kind of equipment I have the habit to pass a screwdriver on the contacts (particularly the ones of the input capacitors) before approaching with my hand, in order to completely discharge them. And a lot of times you can see sparks....

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  • frarugi87 commented on Raulrb's instructable Open Hardware Rover With OpenCV1 year ago
    Open Hardware Rover With OpenCV

    In my opinion, that UNO is totally useless. You can save the money by just integrating the code inside the rPI.Also the two batteries are useless. Just use one (either the power bank or the lipo one) and use a proper circuit to power the other part (a buck converter if you keep the lipo, a boost - if needed - if you just keep the power bank)

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  • Homemade 3 in 1 Multipurpose Workbench: Table Saw, Router Table and Inverted Jigsaw (Free Plans)

    Sorry for the pretty noobish question but... How did you make the cuts for the saw blade? I see one is at 90° and the other at 45°, but how did physically make them? Maybe the 90° is easy, since you just have to try and follow the screws, but the 45° is a bit trickier for me

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  • Simplest 12V to 220V DC to AC Power Inverter DIY

    Cool for demostration purposes, but with a relay rated even for 100k operations using it continuously for 140 operations per second will make it last for about 12 minutes...

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  • Making a Moving, Wirelessly Controlled LED Display

    Maybe it'd be better to put some "delay" between the displays, in order to compensate for the doors, so that the text will appear to "flow" under the doors instead of appearing directly on the other display instantaneously

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  • frarugi87 commented on 3d_printed_brain's instructable 3D Print Your Own Brain1 year ago
    3D Print Your Own Brain

    Sorry, but... Why don't you use a 3D scanner instead of the MRI? You only need to remove the brain from the cranium, but just remember to put it back like it was before and you should be ok...

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  • frarugi87 commented on LarsWH's instructable Smart Rack for Headphone 1 year ago
    Smart Rack for Headphone

    I like this, but there are a couple remarks I have to make:- First of all the Arduino here is overkill here. A simple op-amp or comparator would have been pretty enough.- If you want to use the Arduino, add some functionalities: make it less sensitive to ambient light by modulating the light output, for instance (you can sample the output of the sensor with and without light to see if there is change); or you can make it controllable by the PC, or... well, it has a lot of possibilities- From the HW point of view, not much to say except THE FLYBACK DIODE! Whenever you use an inductive load (motor, relay, ...) you have to put a diode to let the coil discharge at shutdown. The most classical way is to put a diode (best if it is a Schottky one, but for low power even a 1N400x is better than...

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    I like this, but there are a couple remarks I have to make:- First of all the Arduino here is overkill here. A simple op-amp or comparator would have been pretty enough.- If you want to use the Arduino, add some functionalities: make it less sensitive to ambient light by modulating the light output, for instance (you can sample the output of the sensor with and without light to see if there is change); or you can make it controllable by the PC, or... well, it has a lot of possibilities- From the HW point of view, not much to say except THE FLYBACK DIODE! Whenever you use an inductive load (motor, relay, ...) you have to put a diode to let the coil discharge at shutdown. The most classical way is to put a diode (best if it is a Schottky one, but for low power even a 1N400x is better than nothing, even if it is usually slow - note: x is a number from 1 to 7; I usually use the 1N4007, since I don't find 1N4001 around and it cost almost the same) . So the diode goes in parallel with the load, in such a way tha in normal operations it does not conduct (so, in your case, the anode is connected to ground and the cathode to the collector of the transistor)

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  • frarugi87 commented on Elias Stratakos's instructable Custom Wall Tool Holders 1 year ago
    Custom Wall Tool Holders

    Maybe it is a stupid question (I'm not much into wood-working) but... Why did you do the big holes first and then the small ones? Wasn't it easier to first drill the center holes and then use them to center the big ones? Or the big bit you used already left a center starting hole?

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  • frarugi87 commented on TheCircuit's instructable USB Mini PCB Drill1 year ago
    USB Mini PCB Drill

    Isn't the drill bit a bit (sorry) off-center with this kind of linking?

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  • How to Make Rechargeable LED Light Diffuser Using Scrap Materials

    For item 2 I think you are right.. My badAs for the led voltage, yes. As a rule of thumb usually red non-high-brightness leds (those with a red transparent cover) are rated at 1.5V, green non-HB at 1.8V, blue, white and high brightness ones (those with a clear cover) around 3V. But they vary a lot with the manufacturing and conditions (current, temperature, ...) even among the same lot. Usually I find cheap chinese torchlights with some (even 8 or 9) white leds in parallel and powered directly by 2 AA. They work, of course, but the LEDs last much shorter than they would if powered properly...

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  • Manual Controlled Toll Gate Using Push Button

    This is just a start, but... I think your program can be much better.IMHO there are two major flaws with your program.1) you will need to keep the button pressed for on average 500ms (at most 1s) to have it opened, since the control is performed every second2) I think that the servo moves very quickly (usually servos move in a very short time)To solve point 1, you can simply reduce the "delay(1000)" line to, for instance, "delay(50)". After all, when it is closed you do not have to wait.To solve point 2, I'd suggest a complete rewriting of the program. My personal ideal implementation is the one of a finite state machine with 4 states:- CLOSED: when entering, print "Pay toll". Exit conditions: when button is pressed go to opening- OPENING: slowly open the g...

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    This is just a start, but... I think your program can be much better.IMHO there are two major flaws with your program.1) you will need to keep the button pressed for on average 500ms (at most 1s) to have it opened, since the control is performed every second2) I think that the servo moves very quickly (usually servos move in a very short time)To solve point 1, you can simply reduce the "delay(1000)" line to, for instance, "delay(50)". After all, when it is closed you do not have to wait.To solve point 2, I'd suggest a complete rewriting of the program. My personal ideal implementation is the one of a finite state machine with 4 states:- CLOSED: when entering, print "Pay toll". Exit conditions: when button is pressed go to opening- OPENING: slowly open the gate (see details below). Exit conditions: when finished, go to open- OPEN: wait 2 seconds. Exit conditions: when finished waiting, go to closing- CLOSING: slowly close the gate (see details below). Exit conditions: when finished, go to closedTo slowly open/close the gate, you will have to have a part of code executed every X milliseconds that increments or decrements the current position towards the target position. Something likeif ((millis() - prevUpdate) >= 100) { prevUpdate += 100; if (currentPos > targetPos) { if (currentPos - targetPos > 5) currentPos -= 5; else currentPos = targetPos; } if (currentPos < targetPos) { if (targetPos - currentPos > 5) currentPos += 5; else currentPos = targetPos; } servo.write(currentPos);}You set the target position to what you want, then this code automatically moves the servo for you in the desired position.With these values, it will move the servo by 5 every 100ms (this means that the transition 0->90 will take 1.8s).As for rewriting it as a state machine, I implement it with a standard structure (this is pseudo-code). WARNING: very long code, which is a bit generic to show you MY best way to handle this kind of problemsFirst define the states and declare the variable to hold the current state of the state machine:enum SM_states { closed, opening, ... };SM_states current_state;then, in the loop, you have to1) evaluate if there is the need for a state change:SM_states next_state = current_state;switch (current_state) {case closed: if (button_was_pressed) next_state = opening; break;...}2) check if there is a variation in the state, and if so perform any exiting or entering condition:if (next_state != current_state) { switch(current_state) { // Exiting conditions; in this program there is none } // Actually change state current_state = next_state; switch(current_state) { // Entering conditions; for instance in closed you will print "Pay toll" }}3) perform the actions to be performed during the state:switch(current_state) {// In this case you can either put here the servo advancement or do nothing, and advance the servos all the time}With this structure, the program will be much more powerful (changing the program will be very easy, and it is very predictible). This structure can look very complicated, but it isn't and it is easily scalable

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  • How to Make Rechargeable LED Light Diffuser Using Scrap Materials

    Please beware that1) that one is NOT an USB-cable. Applying 5V directly to a LiPo battery will, if you are lucky, only produce the "Smoke-effect"(TM). If you aren't, well, check what an exploding LiPo battery does. If you want to charge it in a better way, embed a LiPo charging circuit in your application2) LiPo batteries should never be overcharged or be used for too long; if their voltage drops below a certain point you will make them unusable (that's what battery monitors are for). Your battey will not last too long without one (unless you constantly keep it well charged)3) Not putting a resistor in series is a really bad habit. This is the first image I found, and as you can see different LEDs behave differently. And can you see how steep is the curve above 3.4V? Very bad ...

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    Please beware that1) that one is NOT an USB-cable. Applying 5V directly to a LiPo battery will, if you are lucky, only produce the "Smoke-effect"(TM). If you aren't, well, check what an exploding LiPo battery does. If you want to charge it in a better way, embed a LiPo charging circuit in your application2) LiPo batteries should never be overcharged or be used for too long; if their voltage drops below a certain point you will make them unusable (that's what battery monitors are for). Your battey will not last too long without one (unless you constantly keep it well charged)3) Not putting a resistor in series is a really bad habit. This is the first image I found, and as you can see different LEDs behave differently. And can you see how steep is the curve above 3.4V? Very bad habit...For the rest.. Well, I particularly like the effect of the silica balls. I will keep it in mind for the future ;) thanks

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  • frarugi87 commented on harishk99's instructable INFINITE TIME SPINNING PENCIL....1 year ago
    INFINITE TIME SPINNING PENCIL....

    Sorry but... Why are you posting the same article with different premises?https://www.instructables.com/id/PRINCIPLE-OF-MAGL...https://www.instructables.com/id/Generate-Electric...

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  • frarugi87 commented on harishk99's instructable Generate Electricity From Magic1 year ago
    Generate Electricity From Magic

    Sorry but... Why are you posting the same article with different premises?https://www.instructables.com/id/INFINITE-TIME-SPI...https://www.instructables.com/id/PRINCIPLE-OF-MAGL...

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  • frarugi87 commented on harishk99's instructable PRINCIPLE OF MAGLEV TRAIN1 year ago
    PRINCIPLE OF MAGLEV TRAIN

    Sorry but... Why are you posting the same article with different premises?https://www.instructables.com/id/INFINITE-TIME-SPI...https://www.instructables.com/id/Generate-Electric...

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  • LUMOS: Smart Lamp for Better Sleep

    Thank you for your reply..Just to point out, my "risky" was not about breaking the MOS (the Vgs max is 20V, so no risk on this side), but on the fact that you may not be able to fully turn it on. Ok, now you have only 2.5m of leds, and I think this equates to roughly 0.5A of current, but then why choose a 75A MOS? Moreover look at figure 1 on the datasheet: look at the differences between 5V and 4.5V to understand how features degrade quickly when near the Vgsth value; then consider these are the typical values (what is typical between 2 and 4V of Vgsth?). Personally, I'd think of using even a smaller MOS (with Id-max between 2 and 20A) but with a lower Vgs-th, to be sure to fully turn it on with 5V or 3.3V.On the other side, ok for the RSSI; but then I think the arduino is su...

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    Thank you for your reply..Just to point out, my "risky" was not about breaking the MOS (the Vgs max is 20V, so no risk on this side), but on the fact that you may not be able to fully turn it on. Ok, now you have only 2.5m of leds, and I think this equates to roughly 0.5A of current, but then why choose a 75A MOS? Moreover look at figure 1 on the datasheet: look at the differences between 5V and 4.5V to understand how features degrade quickly when near the Vgsth value; then consider these are the typical values (what is typical between 2 and 4V of Vgsth?). Personally, I'd think of using even a smaller MOS (with Id-max between 2 and 20A) but with a lower Vgs-th, to be sure to fully turn it on with 5V or 3.3V.On the other side, ok for the RSSI; but then I think the arduino is superfluous. You are NOT using a DAC peripheral on the arduino, simply because there are no DACs on arduino. And moreover a DAC will not work correctly with your setup. What you are using is creating three PWM waves (you can see this with an oscilloscope on the arduino outputs: a DAC creates a steady DC voltage, while a PWM is a square wave and the ducy cycle is adjusted so that the average value is equal to the steady voltage); the rPI is capable of generating this voltage on his own.My personal suggestions are- if you want to change the MOS, choose one with a Vgs-th max of about 1V; this will enable you to use it directly with the rPI- if you don't want to change the MOS, put another stage in between, to power it with the 12V. For instance, put an NPN (or a small nMOS with Vgs-th low) with base towards the rPI, emitter to gound, emitter connected to +12 through a pull-up transistor and the gate of the MOS. This way you will be able to fully turn the IRF on and make performances better.Just a quick search on RS showed that the IRF1404 costs about 2.4€ each; if you change it with a SOT-23 packaged MOS (SMD mount, so smaller circuit - but they are easy to solder also on a perfboard) I found the FDN337N (2.2A of max Id, 30V Vds max, 1V Vgs-th max, 0.24€ each). If you want to stich with through-hole devices, the IRL2703 is in TO-220 case (24A Id max, 30V Vds max, 1V Vgs-th max, 0.98€ each). Again, this is a very quick search on RS; other suppliers will have lots of other devices, with different prices and characteristics. Just pick your favourite ;)

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  • LUMOS: Smart Lamp for Better Sleep

    I see three major flaws in your electronic design (I assume you are using IRF1404, since I could not find any IRF1504)* The MOS is not a logic level one; with a Vth of at most 4V it is risky to use 5V to power it...* Usually it is much better to put a resistor (about 200 Ohm) between any logic pin and the gate of the MOS, because at turn on a high current can flow* Using a rPI and an Arduino is totally overkill. I did not dig into the "machine learning" part, but if it is simple enough to be implemented on a microcontroller (e.g. by tracking the time when the user puts the phone nearby) then you can move it to an arduino (maybe with an HC-05 for the bluetooth). If it isn't, you can directly power the MOS from the rPI (of course, you need a logic level MOS - with a Vgs-th much ...

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    I see three major flaws in your electronic design (I assume you are using IRF1404, since I could not find any IRF1504)* The MOS is not a logic level one; with a Vth of at most 4V it is risky to use 5V to power it...* Usually it is much better to put a resistor (about 200 Ohm) between any logic pin and the gate of the MOS, because at turn on a high current can flow* Using a rPI and an Arduino is totally overkill. I did not dig into the "machine learning" part, but if it is simple enough to be implemented on a microcontroller (e.g. by tracking the time when the user puts the phone nearby) then you can move it to an arduino (maybe with an HC-05 for the bluetooth). If it isn't, you can directly power the MOS from the rPI (of course, you need a logic level MOS - with a Vgs-th much lower). But.. Don't use another complete board just to avoid using a board properlyBest regards ;)

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  • frarugi87 commented on abzza's instructable Ultimate DIY Breadboard Power Supply1 year ago
    Ultimate DIY Breadboard Power Supply

    A few comments.1) using 6 dip switches here can be, IMHO, a problem. You can leave two of them on (then what is the voltage you will have?), or you can open the connected one, maybe to switch the voltage, thus putting the output to 10+ volts, which may fry the board. Maybe it was better to put a switch also on the output..2) you made a board that could arrive to two lanes. Why didn't you make this dual channel? It is much better to have two power supplies...

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  • frarugi87 commented on MartijnS8's instructable Lamp Base Socket1 year ago
    Lamp Base Socket

    In fact, LED lamps are always less than 10W (see that tiny wire inside), so personally I'd avoid powering anything more power hungry than a phone charger. Which makes me say: why do you (=the author) put a 230V socket instead of directly the USB charger?

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  • Add Email Notifications to Any Robotic Vacuum Cleaning Robot

    Just my 2 cents to give you more ideas for the further development1) I'm experimenting with the Telegram Bot library and.. Maybe receiving a notification on your mobile and not the e-mail can be better, even because it is interactive, and it enables 2:2) you can make the arduino "control" the roomba, maybe. I know that some (or all?) of them have an interface to get commands (a serial one? an IR?).. Maybe you can also trigger the start of the vacuuming, get the battery status, .... ?Anyway thank you for this project :)

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  • frarugi87 commented on HardiqV's instructable Amazing ARDUINO Killer1 year ago
    Amazing ARDUINO Killer

    I noticed that the first one is not available anymore... Well, there is this one:https://www.aliexpress.com/item/STM32F103RCBT6-ARM...It even costs less now (3.03 $)... If you want more, I also saw 5pcs bundles for about 17.50$

    Totally right... You can search them on ebay or aliexpress, but here are some links of the ones I bought.I bought my first on Aliexpress (I looked for the cheapest one at the moment I bought it): https://www.aliexpress.com/item/STM32F103RCBT6-ARM...Then I thought I had broken it (it was heating a lot when powered and not connecting), so I needed to replace it quickly. I bought it again on Amazon.it with a 2-days delivery, paying almost 3 times as much (but getting it very quickly:https://www.amazon.it/gp/product/B016IV7MV4Then I noticed that it was just a wire short circuit on the solderings I made, so now I have two working maple mini ;) Anyway from China you can get them for 3-4$

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  • frarugi87 commented on HardiqV's instructable Amazing ARDUINO Killer1 year ago
    Amazing ARDUINO Killer

    I found exactly the same board as yours, but for a very similar price you can get the maple mini. It has the same STM32 micro you have, uses the same Arduino STM32 project, but has a great advantage: it comes with a pre-loaded bootloader. So no FTDI, no bootloader programming, nothing. Plug it in and it works. Just like an arduino board... Only with a much better hardware ;)

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  • Inexpensive Garage Lights From LED Strips

    I highly discourage you from using this approach. If you are using it in linear region, the MOS will just heat up and ... Smoke ;) PWM is used to reduce the power dissipated by the circuit, and is able to better control the luminous output. I'd use an 8-pin attiny for this job, rather than an arduino board, because the required peripherals are already there. You can still program them with the Arduino IDE, and as programmer you can use any 5V Arduino board (uno, mega, nano, ...)

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  • frarugi87 commented on smurray2's instructable RS232 Serial Spy1 year ago
    RS232 Serial Spy

    This works only when the connection is half duplex, right? Otherwise you will not be able to detect both channels..

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  • Pi 3, 2 the MaX for Under £5 - Overclocking - Automatic 2 Speed Cooling

    Why two MOS? Do you use one for a "low speed" variant? I think it is much better to use only one MOS and use PWM to change the speed...

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  • Arduino Nano USB Not Recognizing (Fix).

    I was a bit puzzled at your sentence "FTDI intentionally bricked several of my devices". What happened?

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  • frarugi87 commented on automatic-bartender's instructable Automatic Bartender1 year ago
    Automatic Bartender

    Why RPi and Arduino? I think only one would have been enough.... RPi has GPIOs, or ESP is a lot cheaper; if you want to go cheap use the ESP8266; if you want to make it more powerful (with a bigger database) go with RPi and use its GPIOs to use the pumps.

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  • frarugi87 commented on Henri.Lacoste's instructable Oak Mac mini Case2 years ago
    Oak Mac mini Case

    So you designed a magical box where you put a mac mini, close the lid, use the key to lock it and, after you turn it 360°, the mac disappears? ;-) nice case

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  • frarugi87 commented on Natural Nerd's instructable Vinyl Record Wall Clock - Iron Man2 years ago
    Vinyl Record Wall Clock - Iron Man

    One clock to rule them all... Very beautiful effect!

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  • frarugi87 commented on austiwawa's instructable DIY Color Changing Raw Wood LED Shelf2 years ago
    DIY Color Changing Raw Wood LED Shelf

    Usually the control algorithm is the same, so if you take two controllers you can control both with the same remote (but they won't be synchronized when you start an animation)

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  • Inexpensive garage lights from LED strips

    As the image clearly say, that one is the lighting efficiency (i.e. how much light you get versus the input power), while I was speaking about electric efficiency (i.e. how much power you convert in light versus the input power). Of course LEDs lighting efficiency is the highest among the "consumer" lamps, and I remarked it a lot of times, but they do waste a lot of energy, just like the old ones. Taking the values provided by Steven, a 100W incandescent bulb throws away 95W (and converts the other 5 in about 1500lm, so each "used" watt produces 300 lumens), while an LED throws away 90W (and gets about 10k lm, so about 1000 lumens per each "used" lumen). So the reason why LEDs are more lighting efficient is more related to the fact that they better convert ...

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    As the image clearly say, that one is the lighting efficiency (i.e. how much light you get versus the input power), while I was speaking about electric efficiency (i.e. how much power you convert in light versus the input power). Of course LEDs lighting efficiency is the highest among the "consumer" lamps, and I remarked it a lot of times, but they do waste a lot of energy, just like the old ones. Taking the values provided by Steven, a 100W incandescent bulb throws away 95W (and converts the other 5 in about 1500lm, so each "used" watt produces 300 lumens), while an LED throws away 90W (and gets about 10k lm, so about 1000 lumens per each "used" lumen). So the reason why LEDs are more lighting efficient is more related to the fact that they better convert the "used" power into light (because they output a narrower spectrum, thus avoiding the waste in IR and UV ranges) rather than because they dissipate less heat (because they still dissipate 90% of the input power)

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  • Hundreds of LEDs on Arduino: a New Way From the Past

    I was just starting to design an LED controller for one of my projects and was stuck with the driver selection. Now I think I found it.. Thank you!

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  • frarugi87 commented on deba168's instructable DIY Portable Mini Refrigerator2 years ago
    DIY Portable Mini Refrigerator

    Just a question: Why two fans on the main heatsink? Wasn't one enough?

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  • frarugi87 commented on thediylife's instructable Simple Arduino Home Energy Meter2 years ago
    Simple Arduino Home Energy Meter

    Good to know :) Thank you fot your instructable

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  • frarugi87 commented on thediylife's instructable Simple Arduino Home Energy Meter2 years ago
    Simple Arduino Home Energy Meter

    I'm a bit unsure that the two 100k resistors are suitable for this application. Can you measure the voltage between them to check that it is stable at Vdd/2 even when the CT is working? I would've put at least an OP-AMP or smaller resistors...Anyway for this kind of applications it's much better to use the internal voltage reference...

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  • Programmable Battery Protection [Open Source]

    Uhm.. Maybe there are two versions of your code, but in the image posted in step 5 there is a while loop (while (systemstate == 1)). You exit this loop (and consequently power off the MOS and enter the lop power state) only when the voltage is greater than the threshold AND the button is not pressed. If you enter this loop and the voltage decreases, you will never come out of it..As for the button/switch, sorry, I misunderstood ;) yes, with a switch it will work

    If I understood your program correctly, there are a couple of failure points (or at least I haven't understood everything).1) if you press the button and the battery is discharged, your load will not turn on (ok), but the attiny will never enter the low power mode until the battery is charged again. This is a bad behavior (it should enter the sleep phase immediately)2) as soon as you leave the button the load will be shut down (maybe this is the wanted behavior, though, but I think it is more useful if the button can act as a turn-on - turn-off button)3 and most important) while the load is powered, if the battery gets discharged the attiny will stop monitoring the button, thus leaving the load powered on even if the button is released. This is a real problem...I think that the first an...

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    If I understood your program correctly, there are a couple of failure points (or at least I haven't understood everything).1) if you press the button and the battery is discharged, your load will not turn on (ok), but the attiny will never enter the low power mode until the battery is charged again. This is a bad behavior (it should enter the sleep phase immediately)2) as soon as you leave the button the load will be shut down (maybe this is the wanted behavior, though, but I think it is more useful if the button can act as a turn-on - turn-off button)3 and most important) while the load is powered, if the battery gets discharged the attiny will stop monitoring the button, thus leaving the load powered on even if the button is released. This is a real problem...I think that the first and third points can be solved modifying your code indigitalWrite(mosfet, HIGH);while (systemstate == 1) {if (analogRead(voltdiv) < threshold)systemstate = 0;if (digitalRead(sw) == HIGH)systemstate = 0;}digitalWrite(mosfet, LOW);Moreover you can avoid using the systemstate variable, modifying the loop inwhile (1) {if (analogRead(voltdiv) < threshold)break;if (digitalRead(sw) == HIGH)break;}Best regards

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  • frarugi87 commented on volpin's instructable Creating Costume Armor with Wonderflex2 years ago
    Creating Costume Armor with Wonderflex

    The photos really look like that is an action figure... Great costume and great photos!

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  • frarugi87 commented on makjosher's instructable Cardboard Kitchen Cupboard Organizer2 years ago
    Cardboard Kitchen Cupboard Organizer

    I have to admit, english is not my native language, and when I first saw the first picture I said "no, probably cardboard is not what I think" because... Well, it doesn't look like cardboard anymore. It seems much more solid and professional. Very good job! And thanks for sharing

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