# Pixhawk PMW Signal **URL:** \ **Category:** ArduSub\ **Created:** [July 17, 2017, 12:21pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283 "2017-07-17T12:21:11Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![S4ndm4nn](https://avatars.discourse-cdn.com/v4/letter/s/3bc359/32.png) [@S4ndm4nn](https://discuss.bluerobotics.com/u/S4ndm4nn)\ **Post date:** [July 17, 2017, 12:21pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/1 "2017-07-17T12:21:11Z")
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. ---
**Author:** ![jwalser](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/jwalser/32/2234_2.png) [@jwalser](https://discuss.bluerobotics.com/u/jwalser)\ **Post date:** [July 17, 2017, 12:53pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/2 "2017-07-17T12:53:32Z")
Yes, the Pixhawk can control an LED with a PWM input (like [our very own](http://www.bluerobotics.com/store/rov/lumen-set-r1/)), 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 ---
**Author:** ![S4ndm4nn](https://avatars.discourse-cdn.com/v4/letter/s/3bc359/32.png) [@S4ndm4nn](https://discuss.bluerobotics.com/u/S4ndm4nn)\ **Post date:** [July 17, 2017, 1:00pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/3 "2017-07-17T13:00:51Z")
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](https://pcb-components.de/led-abwaertswandler-buck-step-down/black-power-v3-2800ma-3000ma-5-5v-50v-detail.html) ---
**Author:** ![josef](https://avatars.discourse-cdn.com/v4/letter/j/ec9cab/32.png) [@josef](https://discuss.bluerobotics.com/u/josef)\ **Post date:** [June 22, 2020, 7:29pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/4 "2020-06-22T19:29:07Z")
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](https://us1.discourse-cdn.com/flex019/uploads/bluerobotics/original/2X/a/a8c50e78b491ed9f92d303986c0b61ea042bbf16.jpeg) ---
**Author:** ![Oddmar](https://avatars.discourse-cdn.com/v4/letter/o/6de8d8/32.png) [@Oddmar](https://discuss.bluerobotics.com/u/Oddmar)\ **Post date:** [June 24, 2020, 4:48pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/5 "2020-06-24T16:48:56Z")
I cheat. I just mechanically connect a servo to the pot of a pwm dimmer control. ---
**Author:** ![josef](https://avatars.discourse-cdn.com/v4/letter/j/ec9cab/32.png) [@josef](https://discuss.bluerobotics.com/u/josef)\ **Post date:** [July 16, 2020, 7:10pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/6 "2020-07-16T19:10:28Z")
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 ---
**Author:** ![williangalvani](https://avatars.discourse-cdn.com/v4/letter/w/6f9a4e/32.png) [@williangalvani](https://discuss.bluerobotics.com/u/williangalvani)\ **Post date:** [July 16, 2020, 8:31pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/7 "2020-07-16T20:31:21Z")
Hi @josef, What about [setting it up as a relay](https://www.ardusub.com/operators-manual/outputs.html#controlling-relays)? ---
**Author:** ![josef](https://avatars.discourse-cdn.com/v4/letter/j/ec9cab/32.png) [@josef](https://discuss.bluerobotics.com/u/josef)\ **Post date:** [July 16, 2020, 9:11pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/8 "2020-07-16T21:11:23Z")
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 ---
**Author:** ![williangalvani](https://avatars.discourse-cdn.com/v4/letter/w/6f9a4e/32.png) [@williangalvani](https://discuss.bluerobotics.com/u/williangalvani)\ **Post date:** [July 16, 2020, 9:28pm UTC](https://discuss.bluerobotics.com/t/pixhawk-pmw-signal/1283/9 "2020-07-16T21:28:04Z")
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”.