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PIXEL MODULE COOLING SYSTEMAdrien Stejer
August 18TH, 2017
What are we designing and why?• Pixel modules need to be tested under a range of temperature conditions, ~-30C
• We want to create a tabletop cooling system that can achieve this
• Climate chambers in labs are loud and cost ~$10,000
• Our setup is relatively cheap to make(~$150)
• Components can be bought from commercial companies
• Conclusion: Many of these cooling setups can be made in labs for cheap, potentially
saving thousands of dollars and many square feet of space.
Old Setup
“New” Setup
4
Aluminum
Peltier 2
Plastic
CPU Cooler
Fan
Copper
Arduino
NTC
NTC
NTC
MOSFET
Power Source
Max: 15.4V,
10A
Peltier 1
5
Cold NTC
MOSFETPeltier
Arduino(PID)
Begin Here Args: Input, Output, Setpoint, PID coefficients
Controller connected to power source
Each peltier attached to
separate MOSFET powered by
different power supplies
PWM/DAC
NTC (Negative Temperature Coefficient)
Aluminum
Peltier 2
Plastic
CPU Cooler
Fan
Copper
Arduino
NTC
NTC
NTC
MOSFET
Power Source
Max: 15.4V,
10A
Peltier 1
DAC(DC
signal)
MOSFET
Peltier
• Thermoelectric cooler
• Acts as a heat pump
• Cooling power proportional to I
• Internal heating proportional to I2R so there is
an optimal operating voltage
Issues operating FE-I4 Module with cooling on● Issues with PWM operation
○ Scan operational only for max PWM value
○ Scan fails at any other value
■ Voltage spike on metal in contact with chip
■ Attempted solution: Low pass RC filter
●Ultimately failed because there were still oscillations
in filtered PWM output
■ Next, I tried using a DAC
Issues operating FE-I4 Module with cooling on● Issues with DAC operation
○ Scan operational for a constant voltage value
○ Scan fails when temperature control demands
switching near the setpoint
Noise on the DAC output
Next Steps• Eliminating noise from the system
• Proper grounding
• Manually changing the voltage
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