Pixhawk PMW Signal

Blue Robotics Software ArduSub
1

Hi,

is it possible to use the Pixhawk PMW Signal to dimm an external LED

I got an LED-driver with an PMW input but if i try it the led is only flickering.

2

Yes, the Pixhawk can control an LED with a PWM input (like our very own), but there are some parameters that need to be known:

What PWM frequency does the LED driver require?

  • The Pixhawk PWM output is 200Hz on the Main output pins and 50Hz on the Auxillary output pins

What duty cycle does the LED driver require?

  • The Pixhawk PWM output is ‘RC-style’ with pulse widths ranging between 1000-2000 microseconds.

-Jacob

3

Hi Jacob,

This is the led-driver what im going to use https://pcb-components.de/led-abwaertswandler-buck-step-down/black-power-v3-2800ma-3000ma-5-5v-50v-detail.html

4

I have exactly the same issue as this old post. Have built my own light but when connected (output7) it stays vaguely lit. Obviously the PWM is different range. I don’t need dimming just simple on-off. Any easy way I can achieve that with QGC 4.0.8 (or any other version) the driver info is:

Technical Data PWM input: Max. input voltage: 28V Logic level high : min.2.8V Logic level low : max.0.6V Recommended PWM frequenzy : 150Hz-2000Hz

driver
driver1246×698 49.3 KB

5

I cheat. I just mechanically connect a servo to the pot of a pwm dimmer control.

6

Thanks Darrell,

I am at sea atm and no possibility to go that route. Read every post there is on the topic but unable to find a solution. Was hoping Jacob could point me in the right direction, right now I am diving with the light attached but not connected.

J

7

Hi @josef,

What about setting it up as a relay?

8

Hi Willian,

I thought i needed a physical reley for that. Don’t know i missed that. I only need on off. Thanks a ton, will try it right away.

Best

9

You don’t need a physical relay, it will output either 0 V or (IIRC) 3.3 V on the pin, I guess that will work fine for your setup in “normal mode”.