I would like to use my Earthlistener to monitor the air in the bedroom,
but i’m having trouble getting the backlight off of the VMA412 screen in the VM211.
Setting the screen to “fullblack pixels” isn’t the solution cause i have the SE(clear plexiglas version) and thru the sides of the screen their is to much light escaping.
Is there a Software/Hardware way that i can use to shut down the backlight of the VMA412 module?
Hello @Ard,
Indeed, even if you place a complete black signal to the TFT screen, you will still notice the backlight.
I’m not aware that you can disable the backlight by software, but looking at the datasheet of the VMA412 (https://www.velleman.eu/downloads/29/vma412_diagram.pdf) you can see that the backlight is connected on point K1,K2,K3 and K4:
If you would modify that circuit (you have to cut the trace on the PCB -not the flex cable- and connect it to a transistor which you control through the Arduino), you will be able to disable the backlight.
Please be aware that we do not support modification of the hardware, so this is at your own risk 
.
Regards,
VEL342
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to bad to hear :’(
so anyway :
I’ve bought a new TFT screen 2.8’’ resistive touchscreen V2.0 who can disable the backlight by using Digital pin 3. (of even dim it with pwm)
I still need to modify the code thou of the VM211 in order to support the new screen , as the adafruit gfx lib. did some shenanigans with it’s commands… and it isn’t plug and play…