This idea was born out of a frustration from last year. I was a Scout Master on a National Youth Leadership Training course and I felt that it took to long to launch multiple 2 liter soda bottle water rockets. So I started to look for launchers that could launch several rockets at once but I did not find what I wanted. After searching the internet I found inspiration from several sources and designed the RPL (Rocket Propulsion Laboratory) a multiple rocket launch control center. Not only can you launch water rockets but paper and solid engine rockets as well.
I designed it with lots of lights and switches that get the boys intrigued and relay involved. The launcher I use is located here https://www.instructables.com/id/paper-and-pop-bottle-rocket-launcher/
Here is a video of 4 rockets launching at the same time
Here is a Video from this years Timberline NYLT course with our final launch
Step 1: Parts List
(5) RCA Phono Female Jack Plug Solder Type Audio Video Cable $2.99
(10) 5mm LED light Holder with Chrome Housing $3.00
(1) RED Momentary Push-Button Switch Off-(On) $1.85
(6) RCA Jacks Female Panel Mount Adapter $2.59
(1) Red 12V 20A Car Auto Cover LED SPST Toggle Rocker Switch $2.68
(5) AC 125V 6A ON/OFF/ON 3 Position DPDT 6 Pins Toggle Switch $7.95
(10) Dual Color Led 5mm Green & Red Common Cathode
(1) Electric Key switch Power On Off lock unlock 2 keys $1.28
(5) 25' RCA Cable
(6) Restiors 470-Ohm 1/4 watt
(5) Rectifier Diode 600V
1 Tool Box
1 1/4-1/2" thick scrap plywood
Step 2: Remove Bottom of the Tool Tray
Be careful in removing the bottom of the tool tray it is easy to cut yourself.
I used a box knife to remove the bottom with some effort on the corners.
Step 3: Trace the Outline of the Tool Tray
Place the tool tray upside down on the scrap of plywood and trace on the in side edge.
Cut out the plywood on the line, I used my Dewalt Scroll saw
Paint the top of the board I sanded with 120 grit sanding sponge between coats.
Step 4: Print the Sticker
Print the PDF "Rocket launched sticker" on a full sheet of white adhesive paper.
I went to the print shop and was able to print just one sheet.
Cut out the individual stickers from the sheet and place them where you want on the plywood
Step 5: Drill Holes
Drill pilot holes there are location marked for the pilot holes as you can see in the picture I missed the holes for some of the LED holders
I fixed this on the PDF so you will not have this problem.
After the Pilot holes are drilled flip the board over and drill counter sink holes I used a 1 1/4" Forstner bit this is needed as the hardware is designed to go into thin metal panels and with out the counter sink you will not be able to attach the hardware securely .
Step 6: Drill Holes for the Hardware
Now that the pilot and the counter sink holes are drilled you can start drilling for the individual hardware. Each piece of hardware has a different size requirement so drill the hole slightly large then the threads.
Remove the nuts and washers from the toggle hardware so you can see if it will fit with the thickness remaining in the plywood
if you can attach the hardware you are good
When I attempted to attach the momentary switch I needed to drill the counter sink deeper so that I could fasten the nut and lock washer
With the toggle switch make sure you pay attention to the direction of the on and off direction I screwed up and did not. You can see that I needed to add a third counter sink.
Step 7: Install Hardware
Now that all the holes are drilled lets install the hardware
You can see the extra holes that I needed to add by the Key Switch so I could tighten the nut.
Step 8: Add Hardware to the Tool Box
At this time add the hardware to the Tool Box, the easy way it to pick a location on the back of the tool box. Mark the location and drill the holes.
When fasting the hardware make sure that the cup on the center post is up it will make the soldering much easier.
Step 9: White Wire
The first thing that I did was wire the white wire start at the Toggle Switch and find the ground and start there.
Place heat shrink over every solder point as there is very little room for error.
I found that it was a real pain to try and hold two wires and solder them to the switch. I found a trick that I will show you in the next step.
Step 10: Black Wire
OK after doing the White wire I found a few tricks.
first tin each wire place a small amount of solder on the wire and the connector pin. This because the hardware is designed for plugs and not solder
the second trick is where you a jumping from one pin to the next. Striped 3/4" of the insulation at the location of the next pin bent the wire into a U shape and tinned. This allow me to manage one wire and not two or more,
Step 11: Red/Green LED
In order to complete the Black wire the Red/Green LED needs to be installed
A resistor needs to be installed on the center wire of the LED. I soldered the resistor on and then placed a piece of heat shrink over the joint.
I needed to have a way to hold the LED and the wire, I found that By placing the LED in the holder I could solder and hold the resistor with needle nose pliers as it gets very hot.
After all 5 were completed soldered the black wire to the center and placed heat shrink over the entire exposed area. now determine which side is red and which is green of the LED. I used a 9v battery and some short leads to figure this out.
Step 12: Finish Black Wire
The First pin is a big bundle of wires on goes to the Battery cut this about 18" long the next wire will be used for the jump from switch to switch
there is also the wire from the red LED and the final wire goes to the right side of the of the Red/Green LED located directly next to the switch. Tin all the Wires and the switch pin and then solder the wires together and then solder the big bundle of wires to the pin.
Step 13: Sorry
OK first let me apologize, the rest of the steps are after the fact. I have missed placed the memory card that I took the pictures with and needed to retake some new pictures
Step 14: Red Wire
The main part of the red Wire is the Rectifier Diode bend the leads of the Diode into a U shape solder on the two outside contacts. Then a jumper wire goes from the nearest contact to the red side of the LED (see picture 1). The other contact gets a wire that goes to the center post on the Female RCA jack these are about 18" long so that you can get the tray out of the way for the battery's replacement. Place several pieces of heat shrink around the long red wire but do not shrink as these will be used to group the Red, Green and Blue wires together per switch.
Step 15: Green Wire
The Green wire is also about 18" long and it goes from the green side of the LED to the outside of the female RCA jack. Feed this through the heat shrink on the long red wire.
Step 16: Blue Wire
The blue wire goes from the switch to the outside of the female RCA jack on the same location as the green wire place through the heat shrink and now you can shrink them into place.
Step 17: The Power
I used a series of D sized battery's to get to twelve volts. You could use any 12 volt battery the sprinkler valves are 24 volt but they work well with just the 12 volts.
Step 18: Update 1.1
Well after using the launches several times it became very apparent the valves I used were not up to the task. The jar type valves leak after exchanging them at the "Big Orange Box" they still leaked so off I went to the local sprinkler supply store. After being the butt of several jokes I was able to upgrade to a Rainbird valve that works great.
Step 19: Some Helpful Hints
The boys are really into launching rockets and like to run up to place there rocket on a launcher. This results in them tripping on the RCA cable and unplugging it from the system.
Here is where I have some suggestions. I placed 4 traffic cones out side of the launchers and the control center and placed caution tape between the cones, forcing the Scouts to walk on the outside of the area and placing there rocket on the launcher away from the cables. I also covered the connections with the launcher with electrical tape providing protection from water and being pulled out and unplugged.
I made a Logo I printed them on White and Clear Stickers for the launcher and the Control Center.
I will continue to update as I learn new things.
Step 20: Estes Rocket Adaptor
I was asked if this controller would work with the Estes Rockets. Simply yes of course. Here are some pictures of the adapters that I made for just this reason.
1 RCA female adapter
6" Red wire
6" Black wire
2 Alligator clips
Runner Up in the
Launch It! Contest