This is going to be another entry in my Things I’ve Worked On series. This time I’m going to talk about one of the first things I worked on when I started at an instrumentation facility within a university. This opportunity popped up through a weird circumstance of knowing somebody who knew somebody, but I got the opportunity to work in a new facility at a university which was dedicated to developing new instrumentation in order to help researchers build hardware that would help them do good science.

As a sort of benchmark for my skills, the first job I was given when I got there was to build a micropositioner. This was to help neurobiologists work in some of their animal experiments that involved positioning electrodes quite precisely within the brains of rats. The spec was to control two linear stages with single micron precision and to be able to do so remotely from a rack mount unit.

The actuators themselves were commercial off the shelf. They were made by Maxon Motor and they had a very fine pitch lead screw on them with a brushed DC motor attached by a small gearbox. They also had optical rotary encoders fixed onto the end of the motors. This combined with a spring provided enough precision that you could do single digit micron positioning.

This was a good project to get started with. It involved a little bit of everything, a bit of mechanical design to be able to generate drawings to give to the workshop for them to cut out a front panel and make mounting holes for various things, and it also involved a bit of electronics, power supply, integrating a microcontroller, a display and a user interface. Then also the interconnects to the positioning motors and all the cabling involved with that.

Honestly, it was a bit of a lesson in project management as well and also estimating. I think I overshot my initial estimate by a factor of about two.

Though in the end the project was successful and it was used in many experiments to my understanding.