Cool and Heat with Marlin

Hello RepRapMakers.

I would like to cool and to heat the nozzle, using peltier cells or similar electronics.

Is there a way to select whether to cool or heat?

For example, if I have want to cool, I will connect the peltier as indicated (red to Vcc and black to GND); but if I have to heat it has to change the polarity (red to GND and black to Vcc). And for that, I would like Marlin to indicate the polarity with a pin. It's possible?

Thank you very much!

... hmmm ... sound like an application for a typical "H-bridge", as used for driving steppermotor-coils with the old L297/L298 combo ...

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Viktor
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Hi!

Yes, is a H-bridge with PWM . But, how can I change the bridge direction according the temperature (using Marlin)?