one monkey typing

A couple of months ago I wrapped up physical packaging of the Duckon 20 blinkie kits, but I hadn't decided I was done with the firmware yet. Last night I sat down, tuned up a couple of the patterns, made one new one, then programmed and stickered 200 chips.

So that's in the bag.

Which, of course, means it's time to start thinking about the blinkie for Duckon 21.

Everything showed up at once today. I got the blinkie boards and am quite happy with how they turned out, and both telescope equipment orders showed up today as well. Now I just have to see if I can get the telescope mounted on the dovetail rail and thence onto the mount.

I suppose if I'm snowed in tomorrow without internet service, I'll have something to do.

The board house sent me an email that they'd reviewed the order, found no problems and scheduled it for production. They say "delivery on Feb 10" - I don't know if that means they ship on the 10th or they expect me to have it on the 10th.

Normally they'd have it to me much sooner than that, most people seem to get their orders from them in 10 days worldwide, and that they pretty much always beat their estimates, but the Chinese spring festival is Feb 2-8, so I don't know. If they show up ON Feb 10, I will be able to solder together a few boards before packing for Capricon.

Oh well, they'll get here when they arrive. I do need to order up some other parts though, I originally only ordered enough parts for 100 kits.

EDIT: on lighter news, after hours of looking for someone who even HAD the LEDs that I want, it turns out that not only does DigiKey have them, but in 1000 quantity, they significantly undercut the Hong Kong/eBay sellers.

I did some final, niggling touch-up on the CAD files for the 2011 Duckon blinkie tonight. It's the first board I've ever sent out to have made, and the first board I've designed using CAD - in fact the first time I've used CAD for anything. I was pleasantly surprised at how trivial EagleCAD is to learn, and how pretty much impossible to screw up it makes board layout.

I've been through a bunch of tutorials on EagleCAD and been through design rule checks a dozen times and have everything cleaned up. It's a dirt simple board, but I'm nervous I've screwed something up. But I have a friend from work who's done boards before and he's looked at the Gerber files and assures me that it looks fine, and the prototype that I etched myself works fine.

I sent him a final copy, incorporating the last few nits that he had to pick, and assuming he doesn't come up with any show-stoppers, tomorrow I should be sending the files off to China to have the boards made. With luck there will be show-off boards at Capricon.

I guess I'd better get on eBay and order a whole crapload of LEDs now. And plastic bags to bag up the kits. Then at some point I'm going to have to write assembly instructions, but this is a damned simple blinkie so that should be easy enough.

I just had my first go at etching a circuit board in about 25 years. Last time I did it, I laid the board out on translucent grid paper using sticky pads and tape, and transferred to photosensitive boards.

This time I used Eagle CAD, and blue press-n-peel. I tried using a method that's been documented online, where you print onto cheap magazine paper and then dissolve that away in water. Screwed around for about 3 hours with that. I'm sure someone got it to work, but not me. It turns out I bought some press-n-peel blue transfer material about 12 years ago, and amazingly enough I actually stumbled upon it 2 days ago.

My printer (brother color laser) is really finicky about nonstandard paper, and wound up crunching my sheet of press-n-peel when it finally fed it; it took 5 tries to get it to pick it up. Finally I found a solution online, which is to print on plain paper, then cut out a piece of press-n-peel an inch or so larger than the pattern and tape it over the printed (centered) image on the paper (using the previous print as a location guide) then feed that piece of paper through again so the image is now printed on the press-n-peel. This also allows you to cut out and use only a small amount of press-n-peel. You must use masking tape, others will wreck the printer.

I etched using 1 part hydrochloric acid and 2 parts hydrogen peroxide. This worked great. In contrast to the traditional ferric chloride, this mixture does not stain everything it touches and it's fairly clear so you can watch progress more easily. The fumes are fairly irritating to the mucous membranes from what I've read, though not actually toxic as such. I just cracked a window and had no problems. Another advantage is that apparently this stuff can be refreshed by bubbling air through it; it becomes acid cupric chloride.

The etch isn't perfect, but I learned a lot and hopefully the next time it'll go better. Double sided is a real pain this way. I probably should drill a couple of holes in blank areas of the board in opposite corners and print fiduciaries on the board to line them up properly.

I have the blinkie for 2011 about ready to start laying out board for. The circuit (little that it is) is confirmed working, I'm pretty much done with the software, I have a few patterns in it. I'm currently running a runtime test; since this is a new CPU and a new battery, I want to make sure that the runtime is reasonable before laying out the board, and certainly before paying to have some made.

The blue car seems to have gotten a broken headlamp lens somewhere, and since they're both rather yellow and tired looking, and it's only a little more to get both than to get one, I ordered up a new set on eBay. $80, and installation is about 5 minutes for each. I was going to try to polish them up anyway as the yellowing lenses have been reducing output, so I suppose this is the lazy man's way out.

The 15" telescope goes back in the van this afternoon, and tomorrow around lunchtime I drive to Toledo to deliver it to the buyer. In the spring I *might* decide to pick up a new scope, much more modest and portable, and a modest 3 or 4 eyepiece set, and limit myself to the moon and planets. But only if the mood takes me, and at this point it doesn't feel like it will.
( blinkie video behind cut )

The charlieplexing code is now 100% working. I'm getting some ghosting but that's a circuitry problem and I suspect that it actually has to do with the prototyping board that I'm using. Next time I work on this, I'm going to take the chip off and put it directly on the board and see if the ghosting remains. If it does I have some head scratching to do because my code is pretty much identical to other code I've seen online.

I'm going to order up some Tiny85 chips - I ordered Tiny13s because that's what I'm familiar with, but the Tiny85 is the same chip with 8x as much RAM, which means probably 20x more patterns (lots of the first chunk of RAM will be taken by just the basic code, not pattern code). The difference is only 25 cents ($1.33 versus $1.08). Total parts for this unit may be as low as $3, though the board will probably cost a couple of bucks.

I fixed the wiring bug that I had in the basic charlieplexed prototype that I put together over the weekend. The wiring is confirmed OK. I also drew some charts by hand to make sure I understood what was going on.

Then I got the STK500 development board powered up and a ATTiny13 chip installed and jumpered properly, and wrote a 4 line test program to just blink the first 5 LEDs on and off.

The major issues are:
- figure out how to do deep sleep mode and how to wake from it with a switch on an input
- build an interrupt driven charlieplex display driver.

These are really the only two issues. Doing the patterns and stuff on top of this will be pretty trivial.

Then I need to learn how to use Eagle CAD to lay out the board. I do know a couple of guys at work that have done that before though so I have a resource.