Digital PID controller for a semiconductor laser

• system controlled by an ATmega16 microcontroller, programmed in C language;
• 16-bit ADC converter AD7684 for measurement of LM35 temperature read-out;
• 4-channel, 16-bit DAC converter DAC7734 for controlling the current source in Howland topology to drive a Peltier module;
• LCD display and PC–µC communication (remote setting of parameters).

The PID controllers are used in the Laboratory of Scanning Probe Microscopy and in the Laboratory of Optoelectronics and Fiber Optics at the Faculty of Microsystem Electronics and Photonics, Wrocław University of Technology.