Industry-sponsored engineering project (Harvey Mudd Clinic program) · Aug 2026–present
Illumination Electronics for a Bioimaging Platform
Fluorescence imaging depends on even excitation light, because a dim patch in the illumination looks like a dim patch in the sample. Our team’s bioimaging platform pairs a fluorescence camera with an RGB camera, and each needs its own light source that fits a tight housing.
The excitation ring (my design)
I taught myself KiCad and designed this board from scratch around the LEDs and the mechanical constraints. It has 14 LEDs in series, about 25 V across the string, driven at 700 mA by one channel of a two-channel constant-current driver: roughly 17 W in a ring the size of a lens. The ring has to wrap around the fluorescence camera’s lens without overlapping the RGB lens beside it. It also has a test point at every node, so each LED can be probed during bring-up.
Version 1 was C-shaped with thin copper traces. For version 2, I completed the circle for more uniform illumination and replaced the traces with wide copper pours to spread heat. The final board will use an aluminum core, which allows components only on a single top layer, so the pours do the heat spreading instead of thermal vias. The board is modular, so different LEDs can drop in to excite different fluorophores.
Where it’s at
The boards are ordered, and I’ll assemble them myself with solder paste and a stencil I’m cutting from Mylar sheet. Next we’ll power the LED string from a bench supply, then from the driver, and use the results to order the refined aluminum-core version.
The white-light array (contributor)
I also helped design the white-light illumination for the RGB camera. Four modular LED strips surround the electronics housing, each on its own connector. They feed into a distribution board that takes 1.2 A from the driver’s second channel and splits it into 300 mA per strip. Each strip runs two parallel strings of five LEDs at 150 mA each, keeping the current per string low: 40 LEDs in total. For the prototype, each strip uses LEDs from a single manufacturing batch so the parallel strings share current evenly; ballast resistors or another balancing method are planned for scale-up.