Having recently purchased a starter kit for an Alpha III Model Rocket I was unfortunately underwhelmed with the controller supplied in the kit. The main issue for me being the standard 9volt battery not producing enough power to the igniter to effectively light the engine and launch the rocket. The supplied controller is otherwise a good design (maybe a little flimsy) with the removable safety key which is great feature especially when children are around the launch area. The other problem is, well if your anything like me you will have no trouble losing that particular safety key. Instead of a removable key i opted for a dual action toggle switch and removable launch leads for safety.
My answer to the main issue was to build a more robust unit and beef up the power delivery. I was able to produce the following controller for around $35 including the Li-Po battery. Most of my supplies were purchased at my local Jaycar but I'm sure you could lower the costs buy purchasing online.
All materials are shown in first photo except for the Zippy Compact 850mah Battery and panel mount fuse assembly which were added after my first version failed to impress with a standard 9volt battery.
- project box/ adaptable box
- toggle switch
- carbon missile style toggle cover
- red LED momentary push button
- battery (please check above link for the Zippy compact battery used)
- panel mount fuse holder
- 5amp glass fuse (added for short circuit protection with the inclusion of the LiPo battery)
- panel mount banana sockets (red & black - optional)
- 1mm flex building wire
- right angled spade lugs
- heat shrink (tape could also be used)
- twin cable such as speaker wire with banana plugs at one end and alligator clips at the launch pad end
- pliers for cable stripping and crimping lugs
- battery drill
- 13mm drill bit
- 6mm drill bit
- 20mm holesaw
- gas torch (if heatshrink is used)
- soldering iron & solder