I have set up the camera correctly and confirmed the tiny snapper is functional by connecting it to a servo tester and the Tiny Snapper triggers the camera perfectly every time.
I have set up Mission Planner & Pixhawk to trigger the camera and confirmed the camera trigger function by connecting a servo to the Pixhawk and then triggering the camera using the Trigger Camera NOW function in the Mission Planner flight screen. The servo actuates perfectly every time.
The problem is the camera won’t trigger when the tiny snapper is connected to the Pixhawk. I have tried powering the Pixhawk servo rail with a BEC and I have also tried powering just the tiny snapper with the BEC but nothing seems to work.
I have set up the camera correctly and confirmed the tiny snapper is functional by connecting it to a servo tester and the Tiny Snapper triggers the camera perfectly every time.
I have set up Mission Planner & Pixhawk to trigger the camera and confirmed the camera trigger function by connecting a servo to the Pixhawk and then triggering the camera using the Trigger Camera NOW function in the Mission Planner flight screen. The servo actuates perfectly every time.
The problem is the camera won’t trigger when the tiny snapper is connected to the Pixhawk. I have tried powering the Pixhawk servo rail with a BEC and I have also tried powering just the tiny snapper with the BEC but nothing seems to work.
Thanks for the idea. I have ordered an optoisolator so if I can’t get it going by the time it arrives I will give it a go.
I have also been looking at the voltages between the negative (-ve) and the signal (S) wires coming out of both the Pixhawk and the servo tester. I don’t know a whole lot about electronics but but this is what I found.
To trigger the camera with the tiny snapper and the servo tester I need a minimum of 0.283v between -ve and S wires.
When I measure the voltage between the -ve and S wires on the Pixhawk I get a maximum of 0.279v at max setting of 2200. so it looks like the Pixhawk is not quite putting out enough volts from the signal wire to set it off.
For reference I get 0.366v on the servo tester when I turn it all the way up which is more than enough to trigger the tiny snapper.
Is there an easy way to increase the output voltage on the signal wire? It does not have to go up by much.
you are too hung up in mV , it’s not about the tiny voltage but the PWM it provides. Pixhawk’s PWM is 3v3 , if that is not enough to be registered as “logic high”, then it’s more likely that your servo rail is >5v - reduce the +5v voltage to the device.
Ok thanks Andre. I tested what you said and this is what I found.
You were right about the servo rail being over 5v. In fact it was at 6v so I changed to a different BEC that brought the power down to 5v on the servo rail like you suggested. But unfortunately the Pixhawk still wont trigger the tiny snapper.
Do you have any other suggestions?
This is the main part that I don’t understand: When the tiny snapper and a servo are connected via a Y lead to a servo tester it triggers the camera at half the servo travel. When I plug the same Y lead into the Pixhawk the servo travels its full movement but the camera wont trigger…
And you are back to thinking about it as an analog level/amplitude signal
The PWM is digital, and digital only, whenever the devide trigger shutter, it means it sees a suficcient pulse width over a certain threshold.
If your signal voltage (the positive part of PWM) is too low to be seen as “high” - then the shutter will never fire, because to it, there is no signal (never high).
Usually - good TTL logic accept input as low as 2v as “high” - maybe there’s something funny in the design of that trigger.
Anyway: you can measure the 5V servo rail where it’s connected - it should be close to 5.0volt, then add one diode in series between servo rail +5v and the trigger electronics, with anode in the direction where power comes from (servo rail). -
-this will reduce the voltage the trigger operates with about ~0.6 v, and the 3v3 signal will become relatively higher, hopefully past the threshold for “high”. If not, you can see if the maker of these devices added a resistor between the MCU and input, - or what kind of MCU is used.
