how to control the contrast of GLCD

[mark_s]

Hello,

Maybe something like this using a pnp in a open collector configuration. Much like we control a 12v relay with a NPN and a 5v mcu. Set the PWM to 50% duty and adjust the contrast pot to good level. Now you should have a +/- contrast changing the duty. Basic idea only. Might want to add a resistor and cap to the pwm line to smooth it out.