After looking at what it would take to build a 3D scanner, the most complex HW element is probably the galvanometer scanner. Nicely there are kits sold on Ebay that includes power supply, galvo mount, 2 * (PID driver, galvo) and cables for less than $120. It seems a safe bet to have a working system faster.
The kit is a based on a close loop PID controllers/galvo that apparently allow a 20k points performances at an opening of 20degrees. I’m not sure about the real perfomances of these cheap parts, but as I won’t be trying to get a very fast and complex animation they should do the job.
The manual is not very detailed on the tuning of the system, but once again with some search, the online community is very helpful. There are multiple tutorials (A or B) on the principles and what all each element of the ILDA test vector is testing.
For the laser, I have no experience on what would work better so, I found that Quarton offers relatively cheap modules with a specified divergence (Most of the no-name have no datasheet available). I’ve selected 2 modules to start:
- A small dot module (VLM-650-11 LPA) with a 2.5mm dot at 5m and a 0.25mRad of divergence which should give me a ~1mm dot at 50cm
- A adjustable focus module (VLM-650-02 LPA) to see if I can get a better dot size for the laser
The module here is very convenient to compute the diameter size.
In a future post I will explore the driving signal generation for the galvos and the laser command.