Best way to hookup and PWM a 12V LED Panel on DueX5?



  • What's the best way to connect and PWM a 12V LED Panel on the DueX5? I've poked around some on the forum and in the documentation and I'm not sure whether the heater or fan output would be the way to go since it doesn't look like they'll put out 12V once the pin is disabled from either heater or fan control. Perhaps the answer to this and others can be used to start a page in the documentation for Connecting Lighting?

    Thanks!


  • administrators

    Use one of the fan outputs on the DueX5, or 3 of them if it is an RGB LED panel. If you are powering the DueX5 from 12V, set the V_FAN jumper on the DueX5 to the VIN position. If you are powering the DueX5 from 24V, use the 12V setting and enable the on-board 12V regulator.

    Maximum recommended continuous current per fan output is 1.5A.



  • Thanks Dave! I'll give it a go and report back.



  • Not able to get it to go yet. I'm using g-code to control the fan output with M106 P7 S255. The panel didn't do anything so tried other fan outputs on the DueX5 and nothing. I hooked up my scope to the wire ends and checked the output. The scope shows flat line.


  • administrators

    What position do you have the V_FAN jumper in on the DueX5?

    Have you connected the LED panel wires the right way round to the fan connector?



  • V_FAN jumper is set to VIN. LED wires are connected correctly. I was able to get the panel to work using the Fan 0 output on the Duet WiFi board. I can dim and control it via DWC which is good. The problem now is the panel noticeably flickers at a rate of maybe a couple times a second. Any good way to eliminate this?

    Thanks!


  • administrators

    Is the flickering in antiphase with the flickering of the bed heater LED?



  • Yes, it is. Also, when the bed is turned off or the bed heater LED is not flickering, the LED panel remains lit without any flicker.


  • administrators

    What's happening is that the voltage at the VIN terminals on the Due is dropping when the bed heater turns on. This can be caused by any or all of the following:

    • The output voltage of the power supply is not well-regulated. This is a common problem when using cheap ATX power supplies.
    • The cables connecting the power supply to the Duet are too long and thin
    • The screws in the VIN terminal block are not tight

 

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