Wednesday, April 18, 2012

Further Developments

It's been a while since my last post and I have nothing new to report about the Nixie Clock project. I haven't been sitting still though. In February I got my Ultimaker 3d printer kit. It's a fused deposition modeling (FDM) 3D printer design -- basically a glorified hot glue gun.

I had a lot of misgivings about the design before I got the printer because I thought it wasn't mechanically robust or well-designed. The whole thing is made of lasercut birchwood, and I had no idea how it could have good tolerances with such a design. When I got the printer, I had to spend a few weeks on "calibration" -- belt alignment, print bed leveling, print temperature adjustment -- before I got good speed and accuracy. Unfortunately, I don't have any pictures of parts that I've printed yet but there are some good references and examples online. I'll take some pictures soon of some parts that I have printed out that have impressed me -- either for their mechanical stiffness or the good resolution that I was able to achieve.

Anyway, that's not all I've been up to. I'm building an audio amplifier and equalizer and I want to make it really nice. Although the specs aren't anything to call home about -- a 30W amplifier and a 5 band equalizer -- I've tried to treat it like a serious engineering project and put a lot of design and planning work into it. Here's some PCB board images of the amplifier and equalizer, respectively:

amplifier PCB
Amplifier PCB. Look at those fat traces. I had to leave one wire unrouted because there was no were left to squeeze it on -- I'll fly it across the board.

equalizer PCB
Equalizer PCB. I tried to stick to SMD components as much as possible to save space. The opamps are OPA1644 -- really nice quad chips from TI. Nearly all the resistors on the board are 0603 package. It'll be fun soldering them.

I am getting the boards done through Laen's batch order service. He has a really pretty purple soldermask and the boards usually come back with gold ENIG plating instead of cheaper tin HASL plating. I can't wait to get them back, but there is a +2 week turn period from order to delivery. 

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