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Playing with the PL9823-F5: a breadboardable Neopixel-compatible LED

A fun new part has recently become available – the PL9823-F5. It looks like a standard 5mm RGB LED, with 4 pins and a diffused plastic forming the body of the LED itself.
PL9823-F5 LED
Inside, however, it packs a bit of a punch: a control chip that can set the brightness of Red, Green and Blue via serial data. It’s similar to the popular WS2812 that Adafruit sells as the Neopixel – and it’s fairly compatible with them to boot (the colour ordering is different). According to cpldcpu, the timing of these devices are compatible with the Neopixels, so existing code (such as Adafruit’s library) will work.

There are a couple of important differences: first off, these are through hole, so they’re easier for beginners and hobbyists to work with than the surface mount-only WS2812s. Also, Red and Green are swapped with respect to the Neopixel / WS2812. Other than that, they work identically.

Here’s a link to the PDF datasheet, and here they are on AliExpress. I just paid about $14 per hundred plus a little over $20 in shipping, which is a good deal. The pinout on the AliExpress page is wrong, by the way – use either the one in the datasheet or this fancy hand-drawn one I just made:

PL9823-F5 pinout

Here’s a quick video of 5 of these LEDs in action, running Adafruit’s strandtest sketch:

I’m formulating a few projects that could use these – I need to take a look at how little voltage they can get by on (they’re rated to 4.5V on the datasheet), and how much current they draw. Odds are they’re going to put out a lot of power supply noise much like the WS2812s, so I’ll take a look at that, too.

Category : Blog

Trip Report: Maker Faire Detroit 2013

Maker Faire Detroit Logo
This marks our third time exhibiting at this Faire, and fourth time attending overall. Our project this time was the DIYPinball system, which we’ll get to in a bit. As with years previous, it was a great time but with some lessons to bear in mind in future.

Leaving Ontario
Unlike last year – when all the projects to be exhibited were ready before we left – we started Friday without a pinball machine ready to go. We would up spending nine hours on Friday getting the machine wired and done, only to turn on the power supply for the solenoids and have them all fire at once. This was a bad thing to have happen, considering that the solenoids aren’t rated for continuous use, and that we hadn’t issued the command to turn them on. We shut it down – quickly and with much yelling – and unplugged the solenoids.

Once they were out, we fired it up again, and noticed that:

  • All but five of the solenoid LEDs came on, and
  • The boards were smoking.

More yelling, more frenzied power cutting. We figured that the 2N3904 transistors that drive the solenoid MOSFETs had fried, as they’re only good for 40V, and we were putting closer to 50V across them. Given that it was already 9:00 PM and we had yet to leave Waterloo, we packed up parts for replacement, soldering gear and the pinball machine, and made our way to the Adoba Hotel in Deaborn. We arrived around 2am.

Lessons so far: Have the project ready to test before the day before the Faire, if only so that you know if it’ll blow up the first time you plug it in.

Upon arrival at the hotel, we discovered that I’d screwed up the hotel reservation, booking it for Saturday and Sunday nights, not Friday and Saturday.

Lesson: be more careful with hotel reservations.

With all that sorted, we got about four hours of sleep before we had to wake up, and be at the Faire so we could try and get the pinball machine working.

The next morning, at the Faire
We arrived for check in at around 8:30 AM, sans breakfast or working project. We were inside the museum this year instead of in a tent, which is better for comfort but not as good for exposure – a lot of people don’t seem to venture indoors unless there’s rain (which we got later that day).

Some frantic hot air rework in the booth to remove the 2N3904s and some resoldering led us to find… that we hadn’t fixed the problem (I should point out that all of this is happening while the Faire is in progress). I was about to replace the MOSFETs when I noticed that the transistors we bought for this were rated to 20V, when we’d specced 100V originally. Remember that the solenoid supply is 50V – running that through the 20V transistors lets out the magic smoke REAL quick. We gave up on getting the solenoids working, installed the boards, and tried to get some sort of demo going.

Further testing revealed that the switch inputs worked fine, but that none of the lamps were working. Our first thought was that the matrix scanning speed for the lamps – which was tested with LEDs – was far too fast for the lamps, and it was switching away before they lamp had a chance to turn on.

Slowing it down, however, didn’t fix it.

Even more testing revealed the true culprit: we’d wired the lamps wrong. The lamps had two obvious terminals, with a diode joining them. We’d assumed one was positive and the other negative; in fact, one was floating, basically just there to wire in the diode in place, for the old circuitry’s matrix scanning. The other terminal of the lamp was the bracket itself.

More soldering, and we had the lamps working. With that, we wrote some quick demo code to turn on a bunch of lamps from the left and right flipper buttons, and had ourselves a demo. This was about noon on the Saturday, at which point we donned lab coats and began the exhibition.

Lesson learned: basically, bring every tool you could possibly need to fix the thing.

I was surprised at the interest we got, in a way – I wasn’t expecting people to be that interested in pinball. I must have talked with at least a dozen people who were either rebuilding their own machine, or knew someone who was. The fact that we were using CAN for our system – an automotive networking technology – drew a lot of surprise and interest, which makes sense given the Detroit audience.

Other exhibits
I once again didn’t get a chance to see a lot of the other exhibits. The guys across from us, who were doing EMG stuff, had some VERY cool demos, and a very cool project. They were using electrodes to measure motor neuron activity, and in one demo were opening and closing a robotic gripper by opening and closing their own hand. The other demo was a text-to-speech system designed to let a family member who’d been in a major accident speak again. Sad that they needed it, but well-done stuff.

We had trouble missing the 501st Squadron this year, since we were right across from them. It was an unending parade of stormtroopers, rebel pilots, an amazing Lando Calrissian, Jedi and R2 units. I did not realize, though, that the members of the Great Lakes Garrison were also into other costumes, though it makes sense in hindsight. The Muppet Stormtroopers and the person in the Iron Man costume were particularly good.

The R2 builders were also good. One in particular, who’d been driving his R2D2 around by remote all weekend, did a particularly fine job with a few kids. As the Faire was closing on Sunday, a bunch of kids came across his R2, but didn’t see him. “I think it’s real!” the kids said, as the builder hid behind a pillar with his remote, playing along. The kids posed for pictures and were generally over the moon. Very cute.

Some of the other exhibits I saw were pretty cool as well – HackPGH had their system that turned their glass brick wall into an exterior-facing display, and someone brought a pumpkin carving bot that was neat – but as I said, I didn’t see tons of other stuff. Lesson for next year: more people, and schedule shifts in the booth so that people can see other stuff. I don’t think Mike saw much either, and Alan went a couple times to shoot photos but I don’t think he got all that far.

Entertainment and Refreshments
We’ve got this trip down to either a science or a bunch of closely-guarded traditions at this point. At some point – hopefully Friday but Saturday this year – we hit up the Walmart at Ford Road and Southfield and spend far less on beer than any Ontarian is used to. This year I’m happy to note that we didn’t make fools of ourselves laughing in the aisle at the price of beer in the US.

On Saturday night, we stop at the Five Guys in Southfield en route to the i3 Detroit party and enjoy some burgers. On Sunday, after cleaning up the booth we grab Jet’s Pizza and devour it in the car, taking a photo with the box to make the folks at home jealous.

We stayed later at the i3 party this year than I think we’ve ever stayed before, and had a blast in the process. Lots of very cool people – some Canadian, most not – building cool things with neat stuff to talk about it. I’d had a few at that point, so you’ll forgive me for being light on specifics. I do recall a tricopter with a POV camera transmitting to the LCD TV in the hackerspace that I was sure was going to get tangled in the extension cord hanging from the ceiling. I may have also called Alan names for perceived creeping on other people we were talking with, and I’m pretty sure I started singing the theme from The Polka Dot Door at one point.

I will say that staying out even later the second night was a lousy idea after getting in so late on the first night – we didn’t get back until about 3:00 AM, with two guys from HackPGH along for the ride. Their compatriots who drove were evidently unable to handle partying past 10:30 PM. At the time, I was dismissive of that idea; afterwards, I saw a bit of wisdom in that approach.

Overall verdict: the stuff that happened outside of Maker Faire was awesome.

Mike’s Ford Explorer, when loaded with an AF-TOR pinball machine, is cramped. Alan was in the back seat and was definitely starved for space. We need to either figure out a different vehicle or make a smaller pinball machine for future exhibitions.

I’ll also note that we need a better solution for in-car audio in future. In order to play music from our phones, I brought along my Bluetooth speaker, which I’d purchased for listening to podcasts in the shower. It says on the box, “Surprisingly good audio quality”. It was $20 on eBay, shipped. It’s not sufficient for in car use. Also, if you stick its suction cup to your forehead, dance around a bit, and then try to pull it off quickly, you’ll get quite the bruise. Trust me on this one.

So, yes, the vehicle situation needs more consideration next time. It didn’t suck, but I think improvements could be made.

It was looking pretty grim for a bit there, especially after we blew up the solenoid MOSFETs. Overall, though, it was a great Faire with a lot of interest in our project. Our next step is to get the thing working for Maker Faire Ottawa, and hopefully have something even better to show next year at Detroit.

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Category : Blog &Trip Reports

DIYPinball and Maker Faire Detroit 2013

We presented our latest project, DIYPinball, at Maker Faire Detroit this past weekend, along with collaborators Inventor’s Playground and Useful Robot. More details will be posted on as they become available, but we had a great time and got a great response from a lot of pinball fans.

Category : Blog

New Project: 3D Printer

3D printers are the new must-have tool for people who make things. Personally, I want one for two reasons: designing and building custom enclosures for electronics projects, and putting the heads of my friends on Pez dispensers.

I’ve had the parts for months, and am hopefully going to get it working soonish. Here I want to go over the decisions (if any) behind each piece of the project. (more…)

Category : Blog &Project Updates

Trip Report: Mini Maker Faire Ottawa 2012

NOTE: This post has been sitting as a draft for the last few months. Rather than extensively edit it and thus postpone posting, I opted to make minimal date-related edits and hit Publish.

I (Randy) had the pleasure of attending Mini Maker Faire Ottawa the weekend of October 13th. The Faire was reason enough to come, but the fact that I could also attend my friend Sean’s birthday festivities made the trip a no-brainer overall. I’ll try to break down the Faire itself below, and leave the birthday party itself to the participants, and not the general public (there were lawyers there, and you can’t trust those people).

Maker Faire Organization
This was a very well-run Faire, from my standpoint. The location – Shopify’s lounge area – was just the right size for the number of exhibitors we had (though it did get crowded at times). The organizers and volunteers were friendly and very helpful overall, but there are a few key points I want to highlight:

  • Tables: much better quality tables than at other Faires. Other places tend to go with your standard rental tables that are probably quite old and definitely covered in the pen-written ramblings of a decade’s worth of malcontents, but these were nice and new. I suspect that they were Shopify’s lunch tables.
  • Water: there were two bottles of water ready to go on our table when I got there. A very nice touch – I don’t think we got anything like that at Detroit or New York.
  • Refreshments: the refreshments area was very reasonably priced – 50 cents for fruit or water, a dollar for a can of pop, a dollar for a chocolate bar or bag of chips. Also, as a Maker, I got some vouchers for the refreshment stand each day, which was really nice. When you’re talking to people all day, plenty of water is required.

Overall, a very well-run show.

Other exhibitors
I didn’t get a chance to talk to all of the other exhibitors, and definitely didn’t get to talk to the ones I did talk to for long enough. As much of a trainwreck that sentence is, I can’t think of another way to put it at this point. So a review of the ones I did get to talk to follows.

  • N-Product: their neighbourhood maps laser-engraved into reclaimed wood were beautiful, and the iPod Nano watchband with mini cassette-like loading and recovered bike tires for the band made me seriously consider buying the nano so I could get the band
  • Pelling Lab: lots of interesting DIY biology equipment, like an Arduino system to measure culture growth and a cheap way to make an incubator. The freakiest part was the apple modified to grow muscle fibers – all they really had to do was remove the apple cells with a detergent and infuse muscle cells, they differentiated and formed muscle fibers on their own, apparently.
  • Mod Lab: really neat project where they had people getting their names laser-cut in cardboard and added a blinking LED to it. Being an LED guy, I heartily approve, and the Mod Lab people I met were all really cool. If you’re looking for an Ottawa maker/hackerspace, check them out.
  • Bibz: a video game for Xbox 360, HTML 5 or PC with artwork and level design driven by kids. Really, really cool. I’m wondering if there’s a way to make a custom controller kit so the kids can drive that part of it too.
  • Everyone else. Every one was showing off cool stuff and was incredibly nice.

Our performance
I brought four projects: Interro, StatusLight, the Christmas Ornament and a new one, Project Dickinson. They were all well-received. Those who work in cubicles immediately got the point of the StatusLight. A number of teachers and trainers liked the Interro, which just reinforces the need for field trials to start ASAP. The number of people wanting to buy the ornaments kind of blew me away. Overall, I have a lot of encouragement to start looking at commercializing these projects. That’s going to have to be a key goal for 2013.

A couple of the buzzers finally succumbed to overuse – the buttons in them died. An easy repair to be sure, but it probably means that the final Interro needs to use the 80 cent buttons, not the 20 cent ones. That’s going to raise the cost a bit, I think. I will say that they might have lasted longer had the same couple of kids not come by and slapped / leaned on them nearly constantly Saturday, despite my protestations. Maybe if their parents had been, you know, watching them?

Project Dickinson was well-received as a concept, but not as much in practice, mostly because it worked for about 45 minutes on Saturday morning, and never again after that. It also only started working about 45 minutes before the Faire opened on Saturday, so I probably just need to be more careful about bringing unproven prototypes. I’m holding off on describing it until it actually works, which will hopefully be soon.

Lessons learned

  • Bring spares. Both of project components, and entire projects.
  • Don’t go it alone. Getting breakfast and lunch is important, and is very hard to do if you’re the only one running the booth.
  • Take photos. I have two photos from this event. Should’ve learned this lesson in Detroit, but see above.
  • Booth location. Try not to get the booth directly adjacent to an art project for kids that very quickly turns into a barely-supervised playground.

Overall an excellent Faire and well worth the trip to Ottawa. I plan to exhibit again next time!

Category : Blog &Trip Reports

Maker Faire Ottawa 2012

Another update: Randy is on his way to Mini Maker Faire Ottawa 2012. The following projects are in tow:

It should be lots of fun, and hopefully unlike Detroit, we’ll actually have photos this time!

Category : Blog

Big Update

Hey there! We just updated a ton of pages to have actual, you know, content. We’ve added photos and made source code available from our Bitbucket repositories as well.

The projects updated are:

Enjoy the content!

Category : Blog

Projects from Maker Faire 2012

Thanks to everyone who came out to visit us at Maker Faire Detroit 2012! More information to come, but for now, here are the links to our project source code from the Vending Machine this year:

Category : Blog &Maker Faire Detroit 2012

Maker Faire Detroit 2012

We’re applying to exhibit at Maker Faire Detroit 2012, in conjunction with our friends at Useful Robot and Inventor’s Playground. Some of the projects we’re looking to show are:

  • Project Vending Machine 2, the updated version of last year’s Editor’s Choice Award-winning Project Vending Machine
  • Word Clock, our take on the ever-popular letter grid timepiece
  • SexyTime Watch, Useful Robot and Inventor’s Playground’s fun new wrist-mounted timepiece
  • The UN*X Clock, an open-source clock that shows the number of seconds since January 1, 1970
  • Easydimmer, Inventor’s Playground’s easy way to dim AC lamps
  • NESVerter, our NES-to-USB controller converter
  • Interro, our quiz game buzzer system
  • Useful Robot’s Fencing Box
  • Inventor’s Playground and Useful Robot’s CircleClock
  • and, believe it or not, even more.

Watch this space for updates to our projects and to see what we’ve got coming up. It should be a good show (assuming we get in!)

Category : Blog &Maker Faire Detroit 2012