Well, the prototype power 5V switching power supply that I cobbled together seems to be working. Up there you can see it powering the first nuxx Audio Input Switch, just to give it some sort of load to work on.

Here is a photo of the bottom of it. It’s clearly hacked together, just sort of built up on the board so I could have solder connections and reasonably short wires. When I tried to breadboard it things didn’t work quite right, which I blame on switching power supplies being touchy about long rows of bare wire.

It’s pretty much a reference implementation (some variances in parts) and it produces what appears to be nice, clean power. I can’t see any noise on my scope. Granted, my scope is pretty crappy, but it does seem to show some noise when it exists. (I can’t afford a new scope yet…)

I’m happy with how it is working thus far. I need to put a bit more load on it, but that’ll be done over one of the next random couple of days. For now I can say that it had no problem giving me an even 5.000 VDC while powering the nAIS above and being fed 6.073 VDC. If I cranked the input up to 35.93 VDC (the highest I can get my benchtop power supply) the power supply was pushing out 5.074 VDC. Pretty good, I think.

Danielle’s TV-B-Gone
(Click for full res photo…)

Tonight I helped Danielle put together her first electronics kit, one of Limor Fried’s open-source TV-B-Gone kits. She’s soldered a bunch of stuff before from when she briefly went to Kettering, but this is the first functional kit. And, of course, it works!

Well, it at least turns off my TV almost instantly… I imagine that it’ll work pretty well on whatever other ones. At $20 it’s a good, and useful first kit… Imagine actually being able to turn off all those annoying TVs in places like the doctor’s office waiting room, school hallways, and (hopefully) the advertising things on gas pumps.

Well, there’s that. It works.

I need to finish wiring everything else up and then pursue the group buy idea…

[Later, before I could hit post]

It’s too bad I’m finding problems with the design. Bah.

Transducer in the head of a Toothy Tunes Musical Toothbrush
(Click for more photos (photo gallery retired)…)

As mentioned earlier I had hoped to stop on the way home and pick up a Tooth Tunes Musical Toothbrush. Well, I did. For US$8.99 I grabbed a Tooth Tunes which plays Queen’s We Will Rock You. While I can’t stand that song, it was one of the few recognizable songs on the available brushes, with most of the others being tweenpop.

After eating dinner and playing a bit of E4 I decided to dig into the toothbrush. It definitely wasn’t designed to be easily taken apart, with a metal rivet holding the O-ring sealed bottom in place, and the solid plastic pieces ultrasonically welded together. This meant that most of my disassembly was pretty destructive, but I was able to keep all the electronics inside intact and poke around with them a bit.

The only real problem I ran into is that the IC which holds the audio (and can presumably be reprogrammed) is potted, so it’ll be very difficult to get to. The transducer itself is pretty nifty, and pressing it against my teeth or head or the workbench made the audio quite audible. It doesn’t sound too great, but it at least works.

Anyway, if you’d like to see photos which have better descriptions than the little glossed-over stuff above, just take a look here: Tooth Tunes Musical Toothbrush Dissection (photo gallery retired)