Replication Team - OT2 wireless color sensor

I am working on the replication of a color sensor package with a dual wireless charging port that could be implemented to the OT-2 liquid handling robot. This tool was developed by The Acceleration Consortium (AC) at the University of Toronto.

I will be documenting the process in the replies below.

Bill of materials

I was able to order the components from the provided links on github.io. The Pico LipoSHIM was unavailable through the provided DigiKey links so I had to order them through Mouser Electronics.

Another thing of note was that the link to the Lipo Battery was linked to Amazon.ca. I had to switch over Amazon.us since I am working out of the University of Washington in Seattle.

Other than these changes, obtaining these components for this project was well laid out on from the provided website.

3D Printed Parts

I used a Centauri Carbon and HTPLA for printing.

Initially, the printer was equipped with a 0.8mm nozzle from previous projects. I printed the sensor package wireless charging port using this nozzle with unsuccessful results.

The two enclosures were unable to combine completely flush with the 0.8mm resolution.

Similarly, the sensor package main enclosure would properly couple to an OT2 pipette. I printed the sensor package main enclosure on its 45 degree edge to avoid the need for supports in the stem that couples to the OT2. Since the coupling connection was too small with the 0.8mm nozzle and the stem was printed at this angle, the stem snapped when trying to attach.

I reprinted these parts with a 0.4mm nozzle and these issues were not present.

I started assembling my components and everything was initially going smoothly.

I soldered the LiPo SHIM onto the PicoW and tested the connections turning on the white LED when connecting it to a power supply via micro-USB.


Note I am a pretty amateur solderer, but I feel like it turned out well!

I purchased the exact battery listed in the BOM and switched the polarity as per the hardware assembly instructions. When I plugged in the battery to check for the red LED, I was met with excessive heat, smoke, and a bubbled IC on the LiPo SHIM…

I am not sure why my battery had the opposite polarity than the one in the assembly guild. Looking at the battery again, the one I bought clearly matches the polarity of my LiPo SHIM. Unfortunately since I was “blindly” following the instructions, I did not catch this until it was too late. I have a new shim on its way.

I also assembled/ tested the wireless charging unit and successfully got 5.00 volts on my multimeter.

Currently de-soldering my busted SHIM and waiting on a new one to continue assembly.