Make a Parachute Ejection System

make an electronic, tilt activated latching parachute ejection system for model rockets from just a few simple components.

Finished Product:

Here is a list of the parts you will need:

-Soldering iron
-Solder
-Thyristor
-2 different coloured standard LEDs
-2 100 ohm resistors
-2 330 ohm resistors
-1 220 ohm resistor
-Switch
-9V battery clip
-Ball bearing (tilt) switch
-Wire
-Basic electronic knowlege
-Stripboard or PCB or something to solder the components on to
-9V PP3 battery
-Hot glue gun (optional)
-Screw terminals (optional)

Here is a schematic of the circuit. You could etch your own PCB following the schematic, or modify it sligtly for stripboard (I did) I mangaged to fit it on a 5 hole by 8 hole piece of stripboard (with breaks and joins in the lines)

Now all you have to do is put it together. I would suggest starting with the resistors, then the thyristor, then the battery clip, and finally the LEDs. I just soldered some short wires for the off board components and attached some screw terminals, so I can mount it in the rocket easier and to attach an actual parachute release mechanism. You can do this by attaching a servo or even a piston to where the red LED would normally be, but I will probably make another tutorial showing you how to make that. When you have finished, make sure you check the circuit over, since the battery and thyristor can overheat if there is a short in this circuit. Once you have it all done, you can think about making it fit inside a rocket. I hot glued the curcuit on top of the battery clip so it will sit on top of the battery, and shortened some of the wires. Then, mount the tilt sensor somewhere so it is standing upright. I mounted mine on the side of the battery, although you could put it nearly anywhere. Make sure you test it to make sure it is up the right way. when it is done, you should have something that looks something like this:

When its done, you should have something that looks and operates like this: