This is a model rocket launch controller designed around the Kobalt 24v MAX line of power tool batteries. The battery just snaps in the bottom the same way it would snap into a tool. It may work with other batteries but this is what I designed it for.

My finished design features a master power switch (the toggle with the red cover) and a safety interlock feature. Both push button switches must be pressed simultaneously to launch the rocket. The first button will also light up the second LED and sound an audible buzzer/alarm.

The model is 4 pieces total, and I've included the Fusion 360 .f3d file so you can edit to your liking and specifications. This is fully functional at this point but I still consider it a work in progress, as I plan on making the wire-wrap portion bigger and sturdier.

Not shown in the photos, I would be adding about 15 feet of wire to the wire spool, pushed inside the hole (and tied with an overhand knot so it won't slip out). The end of the wire spool will have alligator clips to connect to the rocket igniter.

The hardware is all M3. There is an indentation everywhere a nut is required so it'll hold it in place as you tighten.

Be sure to use 24v-capable electronics. Here is a list of the electronics I used:

https://www.aliexpress.com/item/Best-Price-10Pcs-Durable-3-24V-Piezo-Electronic-Buzzer-Alarm-95DB-Continuous-Sound-Beeper-For-Arduino/32813767251.html?spm=a2g0s.9042311.0.0.43504c4dbRANI5

https://www.aliexpress.com/item/momentary-push-button-switch-R13-507-OFF-ON/1628167044.html?spm=a2g0s.9042311.0.0.43504c4dbRANI5

https://www.aliexpress.com/item/5PCS-LED-Indicator-lamp-AD16-22-pilot-lamp-22mm-mounting-size-electrical-lamp-12V/32575368706.html?spm=a2g0s.9042311.0.0.43504c4dbRANI5

https://www.aliexpress.com/item/ON-OFF-Toggle-Switch-with-protection-cover/32680784707.html?spm=a2g0s.9042311.0.0.43504c4dbRANI5

And this is an example of the type of battery this will accept:

https://www.lowes.com/pd/Kobalt-2-Pack-24-volt-Max-Lithium-Power-Tool-Battery/1000616187