Wireless Model Rocket Ignition System

Intro: Wireless Model Rocket Ignition System

Welcome! In this 'able I will be showing you how to make a wireless model ignition rocket system. This ignition system can be used with commercial igniters/e-matches in conjunction with the home made e-matches I made in my last project - you can find that project here.

This build will require basic electronic and soldering skills along with ability to use a drill or dremel. If you are under 18 years old you should do this under the supervision of a responsible adult - get dad to help out!

Warning: You are participating in this project at your own risk. I am not responsible any injuries or damage to property as a result of your actions. I recommend using all safety precautions available including working in a well ventilated area, with safety glasses on and other protective equipment. Its not worth hurting yourself because of taking shortcuts in safety!

STEP 1: Tools and Supplies

To build the rocket ignition system you will need to have a few basic tools at your disposal along with the following supplies. Most of the electronics and hardware in this project can be purchased off eBay or from your local electronic store like Jaycar.

Tools:

• Voltmeter
• Superglue
• Screwdrivers
• Heatshrink
• Adjustable spanner
• Soldering Iron and Solder
• Dremel, portable drill or drill press

Supplies:

• Plastic Casing - I used a 197 x 113 x 63mm ABS box - I got mine from jaycar for $7 AU but I would recommend a hinged box as you'll be opening and closing it to change out batteries - see here
• Two channel radio frequency [RF] receiver - Similar to garage door remote control - I found a four channel one here for $11 AU including free shipping
• One 12v "rocket" switch
• Three Nine Volt Batteries*
• Eight AA rechargeable batteries*
• Three Nine Volt Battery Connectors* - 90c each - see here
• One eight AA battery holder* - About $2 each from Jaycar - see here
• One red and one green 12v LED indicator lamp - about $3.50 each - see here
• Length of speaker wire - I used three metres but you may want to use shorter or longer depending on how far away you want the igniter box from your rocket - something similar to this.
• Various lengths of electrical wire - I had mine lying around from past projects - you probably want red and black to make it easy to identify positive and negative when soldering.
• Aligator Clips - you might want to buy these cheap and in bulk because they are going to get toasted every launch!

*In terms of batteries you can use whatever you want as long as they have decent mAH. If you change up the batteries you need to look at using different battery connectors. You basically need to have three different battery connections - one to power the RF receiver, one to power the "firing leads" and "armed" LED and the last to power the "safe" LED.

STEP 2: The Circuit

Before you get started on building your shiney box to contain all of your circuitry you will probably want to build the circuit first to make sure it works. Don't do any soldering at this point as some components such as the LEDs will need to be mounted through the plastic.

I'm not very talented when it comes to electronics, but this projects should be relatively easy for beginners or experienced persons alike with limited electronics experience required to complete it. In looking into the RF receivers available on eBay etc it appears they all have pretty similar layouts. The one that I bought had four terminal blocks, each with three screw in terminals labelled "1, 2 and 3" and one terminal block with two terminals devoted to powering the circuit.

I had two 9v batteries powering the circuit - this should be pretty easy to work out as it will have a positive and negative symbol printed below the blocks. One nine volt battery didn't have enough current to power the circuit thus I used two. Wire up your 9v battery clips in parallel (positive to positive and negatives to negative) then screw the positive wire from your batteries into the positive terminal. The negative wires run from the battery through a switch then into the negative terminal. This switch allows you to turn power to the circuit off.

The way the next three terminal work is the negative cable from the power source goes to terminal "1". Terminal "2" is your negative cable to your LED and firing leads [components]. Terminal "3" is both your positive cable from your power source and the positive cable to your components.

You want the positive cable from your power source going straight to terminal 3. Also screwed in to terminal 3 is the positive wire to your "armed" LED and either one of the ignition leads. The negative cable from your power source runs through the same switch used earlier to terminal 1. A wire should run from terminal 2 to the negative wire for the "armed" LED and to the other firing lead.

You basically now have the circuit needed to cause ignition to your e-match, but as a safety feature you want to wire in another power source for another channel on the RF receiver. This will represent when the circuit is in "safe" mode and you can connect your firing leads to your e-match safely.

The layout for each of the terminal blocks is the same so you need to wire the negative power source wire from the remaining 9v battery clip into terminal 1. The positive power source wire goes to terminal 3 with the wire to your "safe" LED going in the same terminal. The negative wire from the "safe" LED runs to terminal 2.

You should now have a functioning circuit once connecting the batteries. The way to test it is to put batteries in, turn the switch to the "on" position and press each of the buttons on the transmitter that came with the RF receiver. One channel should activate the red "armed" led and also have current running to the firing leads - get out your multimeter and see what sort of voltage you are getting - it should be between 10v and 12v and if its anything less you might have a short in your circuit.

When switched to the other channel your multimeter should show no power going to the firing leads and the green "safe" LED should light up. If this is the case then you have successfully wired it! Otherwise you might need to go back and find the source of the problem. Below is a list of common problems:

• Positive and negative wires are touching shorting the circuit
• Batteries aren't connected or are flat
• Loose connections in the circuit
• Transmitter not functioning
• Receiver not functioning

STEP 3: Preparing the Enclosure and Soldering

Once you've got your circuit sorted and working the next step is to drill the appropriate holes in your enclosure. Use safety equipment including eye protection. Set up your dremel, drill or drill press. If you are using a drill on its own you might need a clamp to keep it steady.

Mark out a centreline that you will use as a reference to line the two LED's and switch up. Drill a hole big enough so the LED bezel will fit through it but the lip of the bezel stops the LED falling out. Repeat for the second LED. Drill a hole big enough for the switch to sit in. Drill two further small holes in the middle of the box for your ignition leads to come from and make a smaller hole for the RF antenna to poke out.

You will need to undo the wires connecting the LED's at this point to fit the LED's in the enclosure. Tighten the screws on both the LED's and the switch to hold them in place. Feed the ignition wires through the two centre holes so that all but about an inch of wire is exposed at the outside of the box. Feed the antenna wire through the third hole and use some electrical tape to secure it to the ignition leads. Re-connect the circuit making sure you have small strips of heat shrink placed on the wire where two wires are connected to each other. Test the circuit to ensure it works.

Solder up all the joints that need soldering and heat the shrink wrap to protect these junctions from causing short circuits.

STEP 4: Finishing Touches and Testing

Now that your circuit is built and all LED's and the switch are mounted to the enclosure you will want to perform a few finishing touches. If your RF receiver came with a two piece small plastic enclosure with screw mounts on the base you can superglue the base to the side of the enclosure then screw the circuit board to it to keep it from floating around. I superglued the 9v battery clips to the roof of the enclosure to hold them in place.

I used velcro to secure the AA battery holder on the internal side of the enclosure as it is slightly too tall to allow the box to be closed if its mounted upright.

Turn on the circuit making sure that the "safe" LED is illuminated. Connect your igniter leads to an e-match/igniter and switch the channel to the "armed" channel. Within a few seconds the igniter should go up in flames and if so you've succeeded, well done!

Thanks for taking the time to read, I would appreciate any suggestions for improvement!

http://youtu.be/EEJh0WqZxhc

STEP 5: *Edit* New Photos

Due to some requests for a simpler circuit diagram, I've taken a few more photos and added one that shows you how to hook everything up. If anyone needs help please PM me.

Comments

[du73]

I have mad the circuit and it works fine except when I ignite the fuse the relay makes a clicking noise I think this is because the wires are shorting out

[Shamuscg]

The relay should make a click when you press the controller button (this is the circuit activating). If you have a multimeter, test the voltage of the two leads that go to your igniter and it should be reading whatever the voltage of your battery is. If it's not reading any volts, it must be wired incorrectly so check all your connections again.

[kddafterburner]

Wired, but nothing happens either I have something incorrect or a bad receiver or transmitter? I am using a lipo instead of the AA batteries.

[Shamuscg]

I can't quite make out for sure, but I think your LIPO negative terminal shouldn't be going to the switch, it should be going to one of the other terminals on the large terminal blocks. The relay should be isolating the power source for the actual ignition leads, not the switch.

[kddafterburner]

Will look at it again! Thanks for responding so quickly! Is there any way you can send me picture of your wiring setup
The one on this page is hard to follow and my printer does not work.Thanks Ken

[Shamuscg]

Hey mate, sorry for late reply. Been busy at work. I've taken a photo, sorry it's a bit of an jumbled mess on this version, I really need to clean it up!

[kddafterburner]

Actually looking on your picture it does show the negative going from your battery pack to the switch?

[kddafterburner]

On your RF board which are the NO normally open and NC normally closed contacts
as my board is marked as such.

Thanks Ken

[Shamuscg]

I think your board layout is the same as mine, it's just labelled differently. If you look at the last photos I put up where I've labelled them, you should substitute terminal 1 for your NO terminal, 2 for your common and terminal 3 for NC. IE your neg 9v (-9v) from the batteries should go to the normally open (NO), the -9v ignition lead should go to the common and then the positive 9v (+9v) cable AND the +9v ignition lead should both be put in the normally closed (NC) terminal. Make sure you test with a multimeter and if your batteries/wires start getting hot/smoking then remove power immediately as it's connected wrong. Hope this helps!

[kddafterburner]

Thanks, that is exactly what I needed to verify!

Ken

[Shamuscg]

Sorry for late reply, if you can post a photo of what your board looks like I might be able to work it out on yours (mine wasn't marked NO/NC)

Cheers,
Chris

[kddafterburner]

Here is the board I have it has two channels and for each it has a commom / normaly open / normaly closed set
of contacts. Need to know which you are using on your setup!

Thanks Ken

[Duggyhow]

Hi, could u please send me a schematic of how to wire this controller. I can't see how u have it all hooked up from the pics u have provided. If I could also have your cell phone number to send u a pic of the rf receiver I have. It has 12 terminals and only 2 terminal blocks. The first one is GND, then 12V, then 1-12 terminals. I need a schematic of how to wire this rf receiver up to get what u have, in other words. I know I don't have it wired right cause the red led light stays on when I put all batteries in the 8 battery holder. I have the red led light negative wire going to the wire that is going into terminal 1 along with the negative ignition wire. The positive red led light wire is going to terminal 3 where the positive ignition wire and the positive wire of the 8 battery holder is also hoooked to. I have the negative wires of the two 9 volt battery clips going to the lead on the switch, then other lead of the switch hooked to ground on the receiver. It turns off the receiver fine. I also have a wire going from the same lead of the switch that the negative wires from the two 9v battery clips are, hooked to terminal 2. My transmitter's light don't light up when I push the buttons so not sure if it's working. I dont have the test circuit wired yet but I will. I just need you to tell me how to wire this thing, lol. Thanks a lot. Please provide step by step how to wire it if at all possible.

[Duggyhow]

Hi, could u please send me a schematic of how to wire this controller. I can't see how u have it all hooked up from the pics u have provided. If I could also have your cell phone number to send u a pic of the rf receiver I have. It has 12 terminals and only 2 terminal blocks. The first one is GND, then 12V, then 1-12 terminals. I need a schematic of how to wire this rf receiver up to get what u have, in other words. I know I don't have it wired right cause the red led light stays on when I put all batteries in the 8 battery holder. I have the red led light negative wire going to the wire that is going into terminal 1 along with the negative ignition wire. The positive red led light wire is going to terminal 3 where the positive ignition wire and the positive wire of the 8 battery holder is also hoooked to. I have the negative wires of the two 9 volt battery clips going to the lead on the switch, then other lead of the switch hooked to ground on the receiver. It turns off the receiver fine. I also have a wire going from the same lead of the switch that the negative wires from the two 9v battery clips are, hooked to terminal 2. My transmitter's light don't light up when I push the buttons so not sure if it's working. I dont have the test circuit wired yet but I will. I just need you to tell me how to wire this thing, lol. Thanks a lot. Please provide step by step how to wire it if at all possible.

[CaleyC]

Could you use a dog shock collar to do the same thing?

[Shamuscg]

I would say you probably couldn't as dog shockers are designed to give a lie current stock as to cause no lasting injury. for this circuit you need a high current to overload the nichrome write and make it burn up.