Assembling the Eyewriter 2.1 hardware platform (rev B)

Picture of Assembling the Eyewriter 2.1 hardware platform (rev B)
This Instructable will guide you through the assembly of a hardware platform (rev B) to support the new Eyewriter 2.1 open-source eye-tracking system.

For more information about the Eyewriter project in general, visit the official site at

For more information abut the Eyewriter 2.1 update that I am working on, check out all of my blog posts related to it:

I am also maintaining a condensed wiki page for the project here:

If you'd rather watch a video showing the assembly process, one is available on Vimeo here:

This Instructable got Featured, which earned me three free months of Pro membership! This means that I can now embed the actual assembly video here for you :)

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Step 1: Gather all of the parts

Picture of Gather all of the parts
Exploded view.JPG
The hardware platform consists of two types of parts: 3D-printed parts and hardware.

All of the printed parts are available at this Thingiverse page. Printing instructions are also available on that page.

Printed parts
- 2 x end blocks
- 3 x platform clips
- 3 x extension arms
- 2 x glint modules
- 1 x main board mount

Look for these hardware items at your local hardware store. But if you live in a place that does not have many metric parts, I've included McMaster part numbers so you can buy them online.

- M8x~20" threaded rod (McMaster: 99055A125, cut to size)
- 4 x M8 nuts (McMaster: 90592A022)
- 2 x M8 lock washers (McMaster: 97985A590)
- 8 x M3x14 machine screws (McMaster: 91420A517)
- 6 x M3 lock washers (McMaster: 91120A120)
- 6 x M3 wing nuts (Grainger: 26L006)
- 2 x M3 nuts (McMaster: 90592A009)
- 1-3 x M3x20+ bolt (McMaster: 92005A128)

Making the threaded rod
You can make your threaded rod any length you want, but I find that ~20" works well for clamping onto laptops and 17" or 19" LCD screens. If you are not able to directly buy an M8 threaded rod at the size you need, you can easily make your own (if you have access to the right tools).

Measure your rod to the length you want, then cut it to length using a chop saw. This will result in a rough edge, which is not only dangerous, but impossible to thread a nut onto. 

Use a bench grinder to smooth the end of the rod out and give it a little bit of a taper. Make sure to test out both ends (cut and uncut) by threading an M8 nut to see if you need to do any more work.
eabdulla1 year ago

Can you let me know from where i can get the code ie software code for it? Thanks

jasonwebb (author)  eabdulla1 year ago

Please refer to the links I posted on the first step. The official Github repo for this project contains all of the source files for this project, including source code and firmware, which you can find here:

Can you upload the files for the glint modules and the ps eye camera so that I can have them printed and ready to go?
jasonwebb (author)  Science Wizard1 year ago
Please refer to the links I posted on the first step. The official Github repo for this project contains all of the Eagle files and Gerbers (for Seeed Studio's Fusion PCB service), which you can find here:
C0UTZ1 year ago
if you use a plain old hacksaw and make your cut in the recess of the threading, you'll find you will almost always have a threadable cut! Useful for those who may not have access to certain power tools, or are lazy (aka me) and don't want to taper the rod ends.
jasonwebb (author)  C0UTZ1 year ago
Great tip! For me, hacksawing seemed pretty labor intensive compared to the chop saw method, but I could definitely see it working just fine :) You could even use a handheld metal file or angle grinder to remove any burrs and smooth the cut out more.
FYI - if you thread on a nut *before* cutting to length, then the threads are re-formed when you remove the nut after... still good to do a *little * clean-up first.
Well, there's always the problem I have which is 'what chop saw?'.

I've never had a problem with a hacksaw and a file to clean up threaded rods.

And if 'cutting a dinky threaded rod and filing the edges smooth' is 'pretty labor intensive' you need to get out more and exercise 8-P

This looks neat and is yet another 'thing on the list' for when I finally get my 3D printer...
jasonwebb (author)  bruce.desertrat1 year ago
Ditto on that, I am just lucky to have access to a modest metal working shop on campus :)

I agree that using a chop saw over a hacksaw for such a simple thing is pretty absurd, but keep in mind the intended audience (i.e. people who may never have worked in a shop before). Different people will have different comfort levels with tools, and will have different access to equipment. I just wanted to recommend the "easiest" way I found to do it, but for someone with even a little bit of background in shop fabrication the definition of that word is up for interpretation. :)

And yes, I do need exercise more, lmao.
Too cool! Great work.