Pixhawk and Relays?

gnaw

New Member
Hi. I am fairly new to this and am calling on all rc buddies to help on an issue I have run into...

Okay, so here is the low down on our issues with this unit:

I am trying to get Pixhawk to control a relay and am using channel 8 on the radio. The relay power in is connected to battery, relay power out is connected to a light, the signal cable from relay is plugged into aux out 5 on Pixhawk. This cable has black, red, and signal. The switch on the transmitter does not turn the light on. My question is does Pixhawk need only the signal wire? Have we missed some other settings? In config/tuning we have first relay pin set to Pixhawk aux 5. We have ch8 opt set to relay on/off.

1.) Official 3DR email support says "all we have is what the wiki says" which is not very helpful

2.) I now powered the servo rail with 5v bec.... ta da!! I can get the relay to turn on but it will NOT turn off. Looks like a one shot deal. Turn on once, stay on until you pull the plug

It seems pretty silly to me - why call it aux out? - Why call it a relay? If there is no other info available other than a wiki that just says "this is a relay pin"?

Its a bit disappointing. Pixhawk was supposed to be the cats ass and a bit more sophisticated than this isn't it?

Channel 8 on the radio is scrolling between 900 and 2000 for on off. In the off position (900), the relay is off. Turn on and the radio goes to 2000 and turns on the relay. Flick the switch back to off (900) and the relay stays on...makes no sense at all.

Does anyone out there know how to fix this and what is going on with this contraption? SOS!
 

Bartman

Welcome to MultiRotorForums.com!!
@R_Lefebvre could probably help with this.

i've had a similar problem with Mikrokopter trying to use a switched ground to actuate a relay. Have you tried opening up the range on the channel's signal.....lower the low end and raise the high end using end point adjustments in the radio (re-reading your post I see 900-2000 but I don't know the range of a channel's output off the top of my head)

you could use a servo controlled switch instead of a raw relay, something like the Pico Switch from Dimension Engineering
http://www.dimensionengineering.com/products/picoswitch

Pololu.com makes something similar with higher amps/current capacity
https://www.pololu.com/product/2804
 

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