Hi everybody,

First, please excuse my limited englisch, as it's not my first language.

I must say, it was a very interesting thread. I have read it from the beginning with great interest. Having the possibility to achieve these kind of precision with just a couple of items that most people have around the house is really mind blowing.

I am also in the process of planning and hopefully also building a fixed gantry cnc mill / router, but aiming at a smaller working area and more rigidity to be able to mill aluminium parts. The work area should be at around 300x300x150mm. I am still contemplating which material to use for the frame, but I might go for welded steel square beams and milled aluminium tooling plates for the surfaces to mount the rails. For now, I just have a set of 20mm chinese square rails and ball screws.

Anyways, while reading through the thread, I was always thinking to myself, why use the cheap USB cams with crappy sensors, when there is such a good Hi-Res sensor in the PiCamera, and the Raspberry pi is a great platform for such projects... but of course, a few pages down the thread and the Pi Camera was used.

A few years ago, I tried building a crude autoguider for astrophotography and used OpenCV and a Raspberry pi with a camera. It worked quite well, and it was able to track a light point while controlling a mount using 4 GPIOs. I ended using PHD guiding in the end, but the effort showed me what can be done with the openCV platform. I was thinking of using it to build almost the same tool that Joe put together in Java, but since the work has already been done, why not use his tool ? :)
By the way, is the development on the Raspberry platform still active ? I have a bunch of Pi's with cameras laying around the house, I could spare one for this project.

Another question: using a laser pointer of decent quality, would it work by shining the laser at a very shallow angle to the sensor, practically stretching the dot into a very elongated oval ? Has this been tried ? I think a forum member already suggested this. Or better yet ditch the laser and use fishing line / piano wire instead ?

Ok, I think it should suffice for a first post :)

Cheers !