ChemHackerSTM 0.1 Schematics and Source Released w/GPL3

With a lot of help, I’ve hit the 0.1 milestone (proof of concept), so it’s time to release version 0.1 of the ChemHackerSTM designs and source code.  As the version number indicates, this is a proof of concept device — if you follow these plans, you’ll get an STM that sort-of works – no promises.

All designs and source code in version 0.1 is hereby released under GPL 3.

The physical microscope is built and works.  It’s still fiddly – I have several design improvements in mind.

The microscope’s electronics work, and will probably not change only moderately between now and version 1.

Video and source code after the jump.

Here is an Eagle schematic of the analog board and tunneling amplifier.

Here is a very basic schematic of the digital side of the microscope (this hasn’t been translated to Eagle yet – I need to create or find a few components missing from my Eagle library).

Here is the Arduino code.

Here is the Data capture code.

Here is the code for translating the CSV data from the data capture code into TIFF (requires the Python Image Library).

Future work:

  • Put all of this stuff up on a Git repository (as soon as I learn how to use Git)
  • Get more reliable data out of the microscope
  • Physical improvements (the current setup is too flimsy and fiddly)
  • Automated approach using stepper motor and fine-threaded screw
  • Arduino-based tunneling current detection (currently a manual process)
  • Automated gain controls (currently hard coded)
  • Scanning speed selection (currently hard coded)
  • The data capture software is at proof-of-concept stage right now and while it works, it needs some serious refinement (and maybe even a GUI).
  • Integration with the excellent Gwyddion open source SPM data analysis package.

Thank you:

John Alexander for publishing his STM designs.

Tim Saylor for Python assistance (data capture from STM to computer).

Carl Karsten for Python assistance (TIFF image processing).

People who kindly allowed me to bounce electronics ideas off them and helped me figure out Eagle: Mitch Altman, Jordan Bunker, Travis Goodspeed, Jeff Kantarek.

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10 Responses to “ChemHackerSTM 0.1 Schematics and Source Released w/GPL3”

  1. John says:

    Wow, that is AMAZING! I remember STM’s used to cost 10′s of thousands of dollars, this is really, really impressive!

  2. Seven says:

    Ok This seems Really Really Cool! And I don’t mean to tear ya down by my ignorance but… What type of Microscope is it? Could you tell me how it works and what it does?

  3. Henk says:

    Hi All,

    Impressive work.
    Years ago I found this one: http://sxm4.uni-muenster.de/stm-en/
    Students from a German university made it.

    cheers

  4. burp says:

    So this does not require a vacuum at all then?

  5. Philippe says:

    Er… pictures, results?

    • Sacha says:

      Hey guys, here’s the answer to your questions:
      Yes, there’s no good data to show – I ran an experiment and gathered data (but I hadn’t written the decoding software yet).

      At the same time, I scheduled the v0.1 design and software release to coincide with OHS and Maker Faire NYC.

      By the time I decoded the data enough to realize I had only noise, it was far too late to attempt a second experiment, and the 0.1 release had already happened – I had to pack the machine for travel to NYC without any data (very embarrassing). So cut me some slack, STMs are really difficult machines to run (this one more than most) and I failed on my very first attempt of ever using an STM. I’ll bet you all failed on your first attempt at using an STM too :D

      I just finished machining a new scanning head – once I assemble it, I’ll make my second attempt ever – probably on Thursday. Check back in a week!

  6. Congratulations, very interesting project. I will send this link to my friends, I know that they will enjoy this :)

  7. Protocol says:

    WOW!! just one question…. how much did you spend on this?

    • Sacha says:

      I’ve spent about $600-800 so far, but I’m doing a lot of experimenting along the way, and I’m buying at least three of everything in case I fry a chip.

      For example, I went through four different DACs before I found a chip that worked well here. All that experimentation and duplication adds up quickly…