A simple arming mechanism for a rocket

[mouniss]

Hello! I am trying to figure out what is the most reliable and simple way to arm a rocket just before flight.

I have had some ideas about multiple MOSFET schemes that short the circuit between a battery and a microcontroller when the switch is closed but enables the action of apogee detection when the switch is open (microcontroller is connected to a magnetometer for detecting apogee and releasing the parachute). But I understood that this idea lacks some sort of feedback from the system that all the components are actually connected and ready to go and that the whole of schematics is rather overly big and complex in my opinion (if 3 switches like this are needed).

The next idea was to simply connect a switch between a microcontrollers 3.3v output and one of its digital input pins. So that after switching the switch microcontroller starts running the rest of code. (Some additional components probably could be added for checking if the rest of all the connections are in place)

Does any of these ideas sound feasible? Maybe some of you knows how this safety check is usually done.

Any help will be much appreciated
Best regards

 

[SkyFire]

https://www.labratrocketry.com/product-page/pull-pin-switch-kit

 

[jimzcatz]

who needs a switch? Just twist 2 wires together and tape them down the side of the rocket.

 

[SkyFire]

who needs a switch? Just twist 2 wires together and tape them down the side of the rocket.

 

[jd2cylman]

But simple and effective... Twist and tape/tuck is all I use. Wires get tucked back into another hole to keep tape in place, and to be able to disarmed w/o disassembling the rocket.
Well, not true. I have one rocket that I bought from a friend. He had it set up for screw switches. I had a set so I stayed with that. Not comfortable with them, but they always made contact. Problem with screw switches is they need a lock nut to keep the screw from moving when it's not supposed to; unscrewing and falling out or making contact when its flat and gravity/vibration turns the screw in. Doesn't happen with twist and tape. Eventually I'll have to replace the wires (I cut off the exposed wire to disconnect the power), but I knew that when I designed them. WiFi switches look interesting, but I'm not a huge electronics buff.

 

[RocketDestroyer]

I make my own screw switches and I use Nyloc nuts. The only time the screw turns is when I turn it. Problem solved.

But simple and effective... Twist and tape/tuck is all I use. Wires get tucked back into another hole to keep tape in place, and to be able to disarmed w/o disassembling the rocket.
Well, not true. I have one rocket that I bought from a friend. He had it set up for screw switches. I had a set so I stayed with that. Not comfortable with them, but they always made contact. Problem with screw switches is they need a lock nut to keep the screw from moving when it's not supposed to; unscrewing and falling out or making contact when its flat and gravity/vibration turns the screw in. Doesn't happen with twist and tape. Eventually I'll have to replace the wires (I cut off the exposed wire to disconnect the power), but I knew that when I designed them. WiFi switches look interesting, but I'm not a huge electronics buff.

 

[crossfire]

Twist and go method has never failed me in 25 years of HPR. Last year used a switch for the first time and on 2nd flight switch broke. No more switches for me.

 

[JoePfeiffer]

You won't get simpler or more reliable than twist n tuck. I use a key switch for no better reason than because I like them.

When you write about feedback and NO/NC switches, are you talking about arming at launch? Typically (in addition to having been armed on the ground) firing the charge requires both a minimum altitude for launch detection and apogee detection.