How do I stop the Arduino TX/RX LEDs from flashing? How do I turn off the "ON" LED?

Question

I actually have a SparkFun RedBoard, but I think this question applies to Arduino Uno and other boards as well.

I'm wondering how much control the programmer has over the various LEDs on the board. First there's the "ON" LED which is very bright. Can this be turned off or dimmed, or do I need to resort to electrical tape?

More annoying is the "TX" and "RX" LEDs. These blink rapidly when data is being communicated over the USB-serial connection. I'm guessing these are not configurable, but I couldn't find the answer anywhere online.

I know that the "Pin 13 LED" can be controlled (via Pin 13!).

Answer 1

I'm wondering how much control the programmer has over the various LEDs on the board. First there's the "ON" LED which is very bright. Can this be turned off or dimmed, or do I need to resort to electrical tape?

Remove it, remove the resistor inline with it, or cut the track powering it. Either that or resort to electrical tape (or blu-tack). You have absolutely no control over it.

More annoying is the "TX" and "RX" LEDs. These blink rapidly when data is being communicated over the USB-serial connection. I'm guessing these are not configurable, but I couldn't find the answer anywhere online.

If your board uses an ATMega16U2

As above, or compile a custom version of the ATMega16U2 firmware and flash it on to the ATMega16U2 chip.

If your board uses an FT232 chip

Download the FT232 EEPROM editing program from FTDI and use that to reconfigure the IO pins the LEDs are attached to so they do nothing. If you are on Linux you can use libftdi's ftdi_eeprom program.

• Malachi: According to Sparkfun the board does use an FT232