I am a beginner working on a project in which I have purchased a device that can display 4 colors on the display (blue, green, yellow, or red). I would like the Arduino to read what color is on the display and depending on the color supply power to an attached motor. For example, if the screen is green supply power to the motor, if screen is yellow or red or blue do not supply power to the motor.

On the circuit board of the attached device there are clearly labelled wires connecting the LCD display to blue, green, and red LED solder points.

Is it possible to read the current going through these wires to determine what color would be displayed on the LCD display? If not, are there any other suggestions which could work?

As I mentioned earlier, I'm a complete beginner so anything would help. Thanks.

Circuit board for purchased device, these RGB wires connect to what appears to be a RGB backlight (picture below of similar backlight to one in device) Image of backlight similar to one in device

  • A rgb lcd display? as the one that adafruit has? adafruit.com/product/398 – Jot Mar 12 at 1:35
  • Do the colors you are interested in seem like an RGB LED backlight to the LCD? Please add some pictures. And can you measure the voltages at the RGB LED solder points when the colors of interest are happening? – Dave X Mar 12 at 3:02
  • The pics look fairly straightforward. If the voltages while on and off are within the Arduino input limit range range, you should be able to read and decode them easily. It might be as easy as configuring three digital input pins, and some code like lights = (digitalRead(D1) <<2) | (digitalRead(D2)<<1) | digitalRead(D3) ; switch(lights){ case 1: /* green */ ..... – Dave X Mar 12 at 14:55
  • what is the device in the picture? ..... it has a UART port ..... perhaps you can use the serial port to ask it about the color – jsotola Mar 13 at 1:41

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