one monkey typing

I've found a place that does prototype circuit boards for very cheap, and I'm afraid I'm very tempted to go a bit overboard on blinkies as a result. I've already ordered one prototype and I will probably do at least two more. I don't know how many will go to production. I also think I will do a few demos on using modules that are readily available on eBay to make one-off blinkies. I think people like soldering together kits, but I also would like to see more people just coming up with stuff on their own. So many people are so much more creative than I am, I'd love to see what they came up with.

I've been falling behind on my personal journaling so I'll just do everything in this post.

Got the rest of the Duckon LEDs in today. Wow. The pink LEDs are PRETTY. We only got enough for 10 sets. They're a bit expensive at $1.20 per set instead of about 60 cents a set for the other colors. I think they're probably going to be gone pretty much instantly. I may change my mind and charge a little extra for them, though that involves bookkeeping that I'd just as soon not have to deal with. Most people seemed fine with just charging a flat rate regardless of color.

I somehow inflamed my left ankle about 4 weeks ago riding bike. It's been slowly getting better. I tried riding last Wednesday but it got a little worse as a result so I left off again. It's almost completely healed but I can still feel a bit of weirdness in there so with only one weekday left I'll wait until Monday to try again. I'm getting to where I've had QUITE enough of driving for a while.

I seem to have fallen behind on 3D printing again. Both machines running to try to catch up. Blinkie kit prep is stalled until I get black PLA loaded in one of the machines again. I do now have all of the LEDs counted out into the kit bags, the rest will only take an hour or so total. Need to write and print the instructions though.

I assembled another demo of the new blinkie, this time with blue LEDs. Then I discovered that these blue LEDs are bright. I mean, they're really, really retina searingly bright.

So I spent the evening adding brightness control code to the firmware. I managed to work it in to the single-button control in a way that I hope is not too confusing.

As a bonus, the dimmer modes should really stretch the battery life - the dimmest mode with the blue LEDs is still reasonably bright, but the LEDs only run 1/255th of the time. For all I know the thing could run a few hundred hours on a set of batteries in that mode even wtih blue LEDs.

Ordered the tactile switches and poly bags from eBay. The CPUs, resistors and IC sockets are in the cart at Mouser but awaiting word whether to drop some more stuff into the basket.

I did the tweaks I wanted to make on the battery holder design (wider slot to push the batteries out, moved the retention ridge down a little to make the batteries more snug, then printed out a few revs at different wall thickness and infill percentages. The final version is very tough, I had to really try pretty hard to break it. It won't break unless someone is trying to break it. I have the first 25 of those being made on the printer right now.

I also grabbed three more breadboards from one of the vendors. They were $9 for 3, what the heck. Mine are so old that the contacts are getting rather corroded and they're not particularly reliable anymore. I think the newest one is something like 25 years old now.

Once again I'll be running the Blinkie room at Duckon 21.

I'm looking for GTers (or anyone qualified that I can grab) who will be there and can help out in running the room. Anything from an hour up would be helpful. Last year I spent from 8AM to 2AM in that room Friday and Saturday, and I'd like to get out of there a bit more. I have some programming I would like to present and can't do it if I can't get out of the room.

Ability to solder and debug blinkies is nice but not a prerequisite - by manning the front desk, taking money, etc, you can free up someone who can get on the floor and help people with their projects.

Usually the technical help is just helping people who don't really know how to solder, looking over a board carefully and finding bad solder joints, parts in backwards, etc.

The blinkie room will be running the same hours as last year, which is a bit less than in prior years. Friday 5PM to 10PM, Saturday 9AM to 7PM.

This is a fun gig, we get to help people make things. I saw a lot of Duckon 20 blinkies being worn around Windycon this year, so people really like them and Blinkies is often cited as one of the most fun parts of the convention. I'm happy to be able to help carry on this tradition. I may also have non-blinkie type things this year, I'm thinking about doing something like having "Useless Machine" kits, which are super easy to make and are pretty fun.

If you can help, please email me, if you have any idea when you'll be able to chip in, let me know that too. I want to get a handle on how much time I'll be able to get away from the room to do presentations. I know that this will be hard to coordinate since many people won't know when they'll be able to help until they see the program book, and I won't be able to say what programming I'll be able to do until I see who can help when.

I'm going to be checking out the new hotel this weekend, getting floor plans and taking pictures of the proposed room and trying to work out how many stations we'll be able to place. Last year we had 24 and that worked out pretty well.

The blinkie ran about 27 to 28 hours with blue LEDs. I think it'd probably run at least another 10 hours with red or green LEDs, maybe 5 more with yellow. Not because they draw less power, but because they will run on fewer volts. The chip will run on practically nothing, I think it'll keep running down to 1.2 volts or something like that, but blue LEDs need 3.2 volts or so to light up, whereas red LEDs will keep running down to I think a bit less than 2 volts.

27 hours with blue is acceptable to me. When I get the full kits in 3 or 4 weeks I'll assemble some with different colors and see how they do.

As always, power source is what drives blinkie design. A single lithium cell worked well for the 2011 design, but 3 volts won't cut it for blue or yellow LEDs, too much forward voltage drop.

Today I've been thinking that a single AAA cell into a 5 volt boost power supply might be doable. I priced out the parts and the with battery holder it comes to about $1.50. The downside is that it's mostly surface mount parts; the boost regulator is only really available in SMT, and most parts are way cheaper in SMT (the exception being the inductor, which is way more expensive in SMT, but an axial inductor could easily be surface mounted manually by just bending the leads down.

But then it turns out that 1-5 volt to 5 volt circuit boards with a USB socket soldered on cost < $4 shipped from China. Simply removing the USB socket then soldering it to the board as a sub-assembly would eliminate sourcing all those parts and more importantly would eliminate that surface mount soldering. It might be the way to go.

A single AAA alkaline cell contains about 1.5 watt hours of power; the CR2032 I used last year has about 0.675 or less than half that power. There is some inefficiency involved in the boost converter of course, but it's still a good deal, and AAA alkalines in 100 packs are cheap, 15 cents each or so.
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Idea bucket - I decided to make a place to record brainstorming for Duckon blinkies and other tech panel ideas. I'm hoping that GT and anyone else with good ideas or opinions will take a look and discuss.

I've JUST put it up and I'm remembering ideas about every 20 minutes now so it's growing fast.

It's on the GT wiki, and I had to lock down account creation due to a spammer invasion, but I'll grant an account to anyone legit.

Please use the discussion tab (top left) to talk on the page.

JohnRidleyProjectIdeas - GT Wiki