As part of my undergraduate study, I did my thesis project at the prestigious Indian Space Research Organization - ISRO, Ahmedabad. The project involved creating a PID temperature controller for the Tunable Diode Laser Absorption Spectrometer. In the beginning I researched and explored different technologies. A laser diode was used in a black box and a circuit was created to measure the intensity as the output. The diode frequency needs to be constant. But, diode frequency would change once the diode would heat up. A Peltier plate with PID controller was thus used to keep the temperature constant. An analog PID controller circuit interfacing with the plates was developed to control the temperature of the laser diode. PID controller would detect the change in temperature and accordingly heat up or cool down the plates. The plates would in turn cool down the diode. We then tested the project using various corner cases. 

I was also involved, as member of the team, in developing and optimizing the spectrometer to improve its efficiency while reducing its overall size. We found and removed all the redundancy within the design. Considering that Arduino Board or any other controller would take up larger space, we developed our own PID controller circuit to help reduce its size. We then used Arduino Board to verify the functionalities of the circuit. This lightweight analog PID controller had an astonishing accuracy range of  ±1° C. This new design will be integrated with the stabilized beam Laser, developed for the forthcoming Shukrayaan-1, the Venus Orbiter Mission by the Indian Space Research Organization, ISRO, India.