Using pixhawk as a relay?

Posted by Gabriel DeVault on March 2, 2015 at 11:52am

I need to short 2 pins on an camera to trigger it. Is there a way to do this directly from a pixhawk? Or perhaps I have to make an external relay circuit driven by the pixhawk? I have tried several RC switches with no luck.

http://www.hobbyking.com/hobbyking/store/__46040__Turnigy_Receiver_Controlled_Switch.html

http://www.hobbyking.com/hobbyking/store/__43894__Dr_Mad_Thrust_Electronic_On_Off_Switch.html

Both of these seem more like they are intended as power supplies and not as actual "switches" or "relays".

The Pixhawk has a "relay" setting, but I guess that is intended to drive a relay, not actually "be" a relay?

I have ordered a picoswitch and I think that will work. But I'm just curious what other solutions may exist...

Thanks!

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Replies

Jean Cyr April 21, 2015 at 7:30pm

The older px4fmu/px4io combo had relay switches built-in you could use exactly the way you want. Unfortunately this useful feature was dropped from the Pixhawk integrated design.
- IdefixRC > Jean Cyr June 28, 2015 at 5:39pm
  
  Hi guyes,
  
  I'm trying to short 2 pins inside a GoPro remote to trigger the camera shutter and have tried a circuit I found in another, older thread. Unfortunately it provides power to the reed relay when the relay is off (0v on the Pixhawk pin) and opens the relay once the relay should be on (3.3v on the Pixhawk pin).
  
  Does anyone know if I can drop 2nd 2N7000 and connect the relay to the first one instead like in the 2nd Diagram below? Or are there issues with that design?
  
  Thanks a lot,
  
  Eric
Jacko March 30, 2015 at 4:43pm

Yes I can make one up for you. It does however needed to be connected (soldered) to the camera shutter button.

Or I can hard wire it for you.

What exactly are you hoping to achieve with it?

We made it to give the most rapid possible capture rate - gives good overlap in windy conditions for one thing.
- Eric Coronel > Jacko March 30, 2015 at 7:15pm
  
  I'm looking for a cable to connect a Canon camera to the Pixhawk for auto missions and triggering. Thanks for replying.
- Jimmy Oliver > Eric Coronel May 5, 2015 at 9:35pm
  
  This is the schematic that works (I'm told)
Daniel Hanson March 30, 2015 at 9:54am

Here is a relay that is designed for use in RC systems. https://www.pololu.com/product/2804

Pololu RC Switch with Relay (Assembled)

This RC relay enables easy control of large, electrically isolated loads in radio control (RC) systems. The activation threshold and direction are c…
Jacko March 5, 2015 at 1:13am

I have the cam trigger you need if you can't get it elsewhere.

Connect to Aux 6 on Pixhawk.

https://storage.ning.com/topology/rest/1.0/file/get/3701949378?profile=original
- Eric Coronel > Jacko March 30, 2015 at 9:36am
  
  Do you sell the trigger cable?
Rodney Johnson March 2, 2015 at 2:22pm

see if this will work

http://www.hansenhobbies.com/products/onboardacc/ers/nersv2/

Hansen Hobbies - Nano Electronic Receiver Switch - V2

Hansen Hobbies - Electronics for Radio Controlled Aircarft