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