If the usb output of the board is a steady ON, you have the 2040 board, not the 2120.
You can wire the 2040 using a Single Pole Double Throw (SPDT) switch, just connect the center terminal to the common ground of the switch and the two outer terminals to the 2040's J1 or J2 inputs. Then you can p...
If the usb output of the board is a steady ON, you have the 2040 board, not the 2120.
You can wire the 2040 using a Single Pole Double Throw (SPDT) switch, just connect the center terminal to the common ground of the switch and the two outer terminals to the 2040's J1 or J2 inputs. Then you can p...