Component Arrival
Over the past couple of months a number of specialized components have arrived for the laser scanner. I shall summarize where to purchase them here.
- Ball Bearings - 2×6x2.5 Hybrid Ceramic/Stainless Steel Ball Bearings from VXB for $4.95/each.
These bearings are designed to be especially “smooth” and have an ABEC-5 rating. In searching for bearings, I learned that all is not contained in the ABEC rating, and the ceramic properties of these bearings provides greater smoothness; though they are not rated for extremely high lateral loads. This is not a problem with a couple-gram rotor. Perhaps less expensive bearings would be adequate, however this is a vital component so it was probably worth it. - Mirrors - small and thin first surface mirrors off of eBay.
- Set Screw Collars - 2mm Metric Set Screw Collars model MC-02 manufactured by Climax Metal Products. Purchased at Fastenal for $1.04/each available only in the (especially cool looking) Black Oxide Finish.
- Machined Galvo Frames! You’re going to have to come up with something for these…
Left to right: US quarter dollar coin, bearing, mirror, and collar.
Completely Offtopic
I highly recommend the following guide for people new to IRC and the unicies:
A Guide to Efficiently Using Irssi and Screen
I’ve been in a bunch of IRC channels lately, including #laserfreak on irc.wiredirc.net, a german channel discussing laser tech, and a bunch of other channels around UIUC.
Can you elaborate on what magnet you used?
Also, what you used for the shaft.
and lastly, did you end up using capacitive or optical for the position detection?
Comment by Adam — November 20, 2007 @ 5:22 pm
Adam,
I use the CYL0285 magnet from the Super Magnet Man at Engineered Concepts, it is very strong. I have gotten both the capacitive and optical setups working. It seemed like they both behaved similarly; i was able to build the RF capacitive PD more accurately, so it worked a bit better, but if you’ve got a good physical construction for the optical, it might work a bit better, and you end up eliminating some of the electronics. Currently i’m just using a commercial system because I could never get my galvos working well enough to project anything worthwhile. My trouble was all in the amps, I’m afraid something was built just slightly incorrectly. Good luck, if you’re building a set I’d love to see them.
Comment by Joey — November 20, 2007 @ 10:47 pm
I will be creating something along these lines. I am not planning on projecting graphics, but rather synchronized slower laser movements, so I am not too concerned about PPS. I am still debating on whether I would like to use/create galvos or if i’d rather just use a stepper or servo setup. galvos seem like a fun project to attempt so I am kind of leaning torwards that route.
How was the trouble with the amps? Were you pulling too many or too few? Do you have any ideas on what could have been causing it?
Comment by Adam — November 22, 2007 @ 1:21 pm
Adam,
If you’re interested in doing it for the experience of building galvos, I highly recommend Norm’s kit. It will help you go down the right path. Just google “Norm galvos” for the link. Steppers or a servo will likely create jittery output–I think you will likely need galvos whether they be home built or commercial.
The amplifiers were just always impossible to tune. I think I had some incorrect gains in the design that didn’t match the physical response of my galvos. The system just remained unstable.
Comment by Joey — November 23, 2007 @ 3:37 am