2017 · ODE Lab · Harvey Mudd research
Research in the Open Devices Engineering (ODE) Lab, which builds low-cost, open-source instruments for semiconductor fabrication. My main project was a network analyzer that cost about $15 to build.
Measuring the resonant frequency of a MEMS cantilever usually takes a benchtop network analyzer, which is too expensive for a low-cost lab-on-a-chip system. The lab builds open-source instruments, so the goal was to make the same measurement with about $15 of parts.
I designed, built, and tested a PCB that generates and measures sine waves from 10 kHz to 20 MHz. I set up the STM32 and wrote embedded C to drive a direct digital synthesis (DDS) chip over SPI. The toolchain was open source, so others can build it.
I looked at time-interleaving as a way to raise the effective sample rate without using expensive high-speed ADCs.
I also built other hardware for the lab: an Arduino-like STM32 board, an LED-matrix PCB for a spectrometer prototype, a clip-on JTAG connector for faster programming, and Hall-effect sensor tests for RPM control on a spin-coater.
The analyzer measured a cantilever’s resonant frequency for about $15 in parts.