Remote Ignitor - joshuarothfuss/projects GitHub Wiki
The idea behind this was I can't always personally be there to perform a start sequence. Be it because it is, on an RC airplane, or that being too close is dangerous. I've wanted to launch a model rocket from an airplane for some time now. I've also wanted to use a drone to drop a payload. I need a way to light rockets and release claws.
Tools/Skills Used
- Soldering
- Basic Circuit design
- C Programming
Design/Testing
The initial plan was rocket ignition. I needed to turn a PWM signal from an Airplane receiver into a long pulse that could engage a MOSFET. This was achieved with a servo reading library on platformIO. The next issue was the reliability of model rocket ignitors. For every 3 rocket engines you buy, they give you 4—5 Ignitors. That is only 60% to 75% chance of working. I went with something cheaper, more abundant, and more reliable. 1/4 and 1/2 watt resistors are the perfect size to friction fit into the rocket engines. If you bend them as shown and apply Kapton Tape to one side, it is very reliable. I tried 1ohm—330ohm resistors and found that the 3 best were:
- 5.1ohm
- 2.2ohm
- 1ohm
Results
The result was a 3 channel remote Ingitor. The remote can be configured to have 3 switch activate a different channel. The biggest use was the 40mA-max on the GPIO pins. It also took 1—2 seconds for the resistor to reach its auto-Ingition point. See attached video for a demonstration.