Low cost STM projects – A review

I’ve been reviewing some student/hacker attempts at building low cost STMs. The major challenge in an STM project appears to be the coarse/fine grained approach mechanism, and there are a few options. this review is also pretty useful.

Unimorph disc projects

unimorph_xy

disk_drawing_elec_s

disk_drawing_sidewp

These projects use a standard Piezo buzzer cut into 4 quadrants. The tip is mounted in the center, the setup seems to produce reasonable (but far from perfect) results. I’ve seen a couple of projects based around this idea. The earliest seems to be John Alexanders project which is now only available via the Internet archive.

The second is a Colorado State University project that was presented at a conference, the paper is linked here:

2006-2314: A NANOTECHNOLOGY EXPERIMENT: DESIGN OF LOW COST SCANNING TUNNELING MICROSCOPES, Nebojsa Jaksic, Colorado State University-Pueblo: pdflocal copy

This project from the University of Hannover is also similar (nicely done, though light on details): pdf local

There’s also this project from AFEKA, Tel-Aviv: pdf local

Another awesome project by some HIGH SCHOOL students Switzerland is also documented here they didn’t complete it, but took some measurements. In particular their journal contains a lot of interesting information. (local copy: journal paper).

More recently Dan Berard documented a excellent project on his website which includes a lot of very useful information.

Bimorph benders

bimorphstm

I’ve come across one project that uses Bimorph benders blackford1987. The opamp used is an AD611.

Piezo Tubes

Piezo tubes are used in commercial STMs, but they’re actually not that expensive to buy in small quantities, it just takes a bit of work to hunt out suppliers. There are more details on my Piezo actuator review post. This project planned to use a Piezo tube and has some great information.

This paperAlso uses a piezo tube in a low cost configuration.

This paper is another such project.

And another: hipps1990

Amplifier notes

A paper on STM amps: lownoiseamp

Here’s another detailed paper on amp design: holt2012