Quote:
Originally Posted by hooverphonique
You can power them using 5V from the Pi, but you still need a transistor (or other switching element) to drive them. Something like the schematic below - the stuff in the box is the existing keyboard circuit, so you just connect its GND pin to ground and PWR or DRIVE to the circuit shown to light a LED. Unfortunately, the LEDs are high-side switched, so you need two transistors to control them from 3.3V (unless you want to hack the keyboard).
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Single PNP transistor can be used as in orginal Amiga schematic but negative logic (i.e. 1 disable LED and 0 enable LED) and pullup resistor required but still IMHO best way (RPi safe) is to use cheap optocoupler.