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Model Rocket Launcher

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New Member
i also fly model rockets, and also found the need to use multiple launch pads, a while ago i designed a circuit that allows me to send 6 seperate signals down a 2 core cable.

if this is of any interest to you pmme and ill send it to you, i have since moved over to 2.4ghz launch setup of which im still ironing out a few issues.

where in the world are you?? and what do you fly???

im currently working with e,f,g engines.


New Member
Hi Johnny,

here is the screenshot of the operating panel.

The bottom row of LEDs indicate counter state (simultaneously firing), the top row indicates a valid continuity check of the corresponding "channel".

Those LEDs remain dark if the igniter is interrupted or shorted.




New Member


New Member
Greetings jholguin

In the interest of safety, one thing you may wish to consider is that MOSFETs very often fail short circuit. It may be worth including LEDs to monitor each firing circuit for voltage to avert an unintended ignition at the launch pad. I myself have be flying model rockets for 20+ years and witnessed a launch pad accident involving serious burns.
Where are you getting your MOSFET failure data/history. Can you provide failure references?



New Member
the 4017 reset line is incorrect on the first schematic.........


New Member
Never seen a MOSFET fail as a Drain to Source short. The only way I've seen them fail is Gate to Source leakage (which keeps them OFF). Overtemperature usually melts the PCB solder connections, opening the circuit when the MOSFET falls off the board.


I would recomend using high current relays instead of MOSFETs, simply because the igniters can be hard to "Light" some times.
In the years we launched rockets we had the battery right at the pad and short heavy wires to the igniters. Relays will not usually fail shorted and provide a low resistance path to the igniters. IgnitersThey might be listed at 1 amp but with voltage drops you can get a lot of misfires. It is also nice to have a launch interlock key that can be removed and carried with any one working on the pad to prevent accidental launches.
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