Connecting an altimeter on a relay?

Hello,
Does anyone have experienced an altimeter connection with a relay or selenoid? I want to try releasing parallel boosters with the help of an altimeter, preferably a Raven. I would like the mechanism to works with selenoids rather than black powder.

It should also be that the mechanism opens at least one second.

All suggestions are welcome.
Thanks,

Steeve

I am think the Raven can latch an output, but I am not sure what the solenoid you want to use can be driven by that output.

You might need a transistor driver for the solenoid. It converts the altimeter output to a level that will operate the solenoid. Shouldn't be difficult to implement.

I do not have solenoid for now, I just want to know if anyone has tried it. I imagined the use of a relay with independent circuit for the selenoid. But if no one has tried, all suggestions will be considered.
There's a command in the FIP that state: HOLD THE SWITCH CLOSED CONTINUOUSLY, that can (?) help me activate a relay. And I think some relays can work by small electric impulse and can remain open or closed.
I have just written to Adrian to see if he can help.

Thanks Mark!

You don't want to use a relay in a rocket because they can be opened (or closed!) by vibrations and G-forces. Use a power transistor instead. Note that you're also going to have to put a reasonably-sized resistor (maybe about 39 ohms) across the deployment outputs to trick the altimeter into thinking that it's got an igniter there, otherwise it will fail the continuity check and you won't be able to launch with it.

cerving said:

You don't want to use a relay in a rocket because they can be opened (or closed!) by vibrations and G-forces. Use a power transistor instead. Note that you're also going to have to put a reasonably-sized resistor (maybe about 39 ohms) across the deployment outputs to trick the altimeter into thinking that it's got an igniter there, otherwise it will fail the continuity check and you won't be able to launch with it.

Click to expand...

Good point! Thanks

Steeve

FYI Sparkfun sells a mini-solenoid with a 4mm stroke thats 1.125"x.5"x.5" approximately, I have been looking at them for a similar idea of booster release, ultimately thought I think I am going to go with a system using black powder and shear pins for simplicity.

On one of the bigger projects I Know they actually manufactured an explosive bolt. Basically drilled out a nylon screw, filled the cavity with BP and an e-match) the used the altimeter in the same fashion as for deployment. Of course this was the giant Delta and your scale may be too small. You could possibly use a string pulling the two booster together across the body interior and a cable cutter to sever it.

H_Rocket said:

On one of the bigger projects I Know they actually manufactured an explosive bolt. Basically drilled out a nylon screw, filled the cavity with BP and an e-match) the used the altimeter in the same fashion as for deployment. Of course this was the giant Delta and your scale may be too small. You could possibly use a string pulling the two booster together across the body interior and a cable cutter to sever it.

Click to expand...

I bought a cable cutter last year for this idea. The problem is always going to install all this in the middle of a rocket. But if this is the best way, I will try. I even machined a UHMW bloc for two cable cutter for redundancy. Using one tie cable through the boosters and the main rocket and another to lock that first cable into the last booster. Springs would be inserted in the cable tie each side of the main rocket airframe to help separate the boosters from the main rocket. My main concern is I want to use long burn motors in this rocket; specially the strong ones. The K300 and the L395 are the strongest but have also long casing.

Here's what I'm actually planning; Note that with Open rocket you can't add nose cone to "pods".
That mechanism must be above the gray casing.

Do you think I can add a bulkplate and set up the cable cutters there? I won't use motor ejection. I guess I could also use a removable av-bay style coupler with the cable cutters inside. This airframe can be separate at the transition/airframe junction. Above the transition is the av-bay.

Thanks for all the suggestions, it helps alot.

Steeve