Robotics

Useful links

Here is a link back to the liquid handling page.

Open source laboratory automation

I had a student who needed a project a few years back. We made this nightmare of automation. It has an eight channel pipettor on movable X- and Z-axes. The pipettor is controlled by two servo motors that control the dispenser and tip ejector. On the Y-axis stage are boxes of tips, a 96-well microtiter plate, a solvent reservoir trough, a petri dish, and a receptical for waste tips.

The firmware was pretty straight-forward and we made a lot of progress on the user interface. The problem here is the complexity of the tasks that can be envisioned for such an instrument. While a commercial manufacturer could power through this, writing semi-repetitive code for different experiments is not the kind of task one assigns to a series of undergraduates. There is essentially no end to the code you can write for this thing.

The project was supposed to help a colleague who studies viruses that infect bacteria. While initial results were promising, the student working on the project graduated and the project languished. The robot is sitting in my garage right now, waiting to be transformed into a CNC mill dedicated to manufacturing printed circuit boards.

Suggestions for the next prototype

If I were to make another of these, I would have a fixed bed and have the gantry move in the Y direction. That would minimize the overall size and allow the robot to be contained in a smaller box. I think the box is necessary to avoid sample contamination.

I would also re-design the electronics to use TMC2209 motor drivers that could allow sensorless homing using their stallguard feature.