posts tagged with the keyword ‘arduino’


Rotary Encoding

For an upcoming project we want to use rotary encoding with optical sensors, so I did a bit of hacking testing today…

I’m using two photo interrupters mounted on breakout boards with 220 ohm resistors.

For an encoding disk I searched for a suitable SVG file and found this blog post, which just happened to have a link to a perl script (of course!) to generate encoding disks. A little Inkscape magic and I printed out a disk to test with.

I should note that my original plan was to use the Silhouette Cameo to cut the slots in the disk, but the paper version actually worked fine for testing. In the final piece we’ll probably use a piece of laser-cut acrylic.

With my encoding disk ready I hot glued it to a bolt and chucked it in the drill. This gave me an easy way to vary the speed and direction.

Rotary Encoding

I grabbed the Encoder_Polling library and used the counter example and that was about it. I could now see if the disk was spinning and in which direction (by looking at the numbers increase or decrease.)

I really thought I’d need to mount the photo interrupters more precisely, but I pretty much left them hanging in mid-air supported by wires on a breadboard and it worked fine. (Maybe I just got lucky?) There’s a lot more code to write, but this was a good start.

Oh, if you want to learn way too much about reading rotary encoders with an Arduino, visit the Reading Rotary Encoders page and set aside a few hours…

Note: I also found an online encoder wheel generator.


Teensy 2.0
Teensy is teensy

For the past few years I’ve been building devices that can emulate computer keyboards. Typically I’ve used the Teensy microcontrollers for this along with the Arduino IDE and the Teensyduino add-on. The things you can do with a Teensy to emulate a keyboard are very impressive! Basically, it’s the best way I know of to create your own custom USB keyboard.

Size matters – A-Star with Arduino Micro and Leonardo

When the Arduino Leonardo was introduced, one of the features I was interested in was the ability to emulate a USB keyboard. I never actually got a Leonardo to test this with, mainly because the form factor was too large for my projects. Sometimes shield compatibility is good, sometimes the smallest board wins.

Size matters!

I recently got a Pololu A-Star 32U4 Micro, which is a tiny (and cheap, under $13USD) board very similar to a Leonardo, once again using the Atmel ATmega32U4.

There may be a little bit of work involved in getting the A-Star up and running. There are drivers needed if using Windows, and (supposedly) a little more work to get things going with Linux. I had no issues with Mac OS X, but I’m pretty familiar with add-ons for the Arduino IDE due to using Teensyduino. You can also just pretend this is an Arduino Leonardo and that seems to work fine.

(I also can’t tell if the Pololu A-Star 32U4 Micro is open source hardware. They do have a bunch of files available, but I did not see an explicit “Open Hardware” note anywhere. It’s worth mentioning that the Teensy is not open source hardware. If that’s not a big deal to you, then it’s not a big deal to you. The official Arduino hardware is of course, open source.)

I’ll probably keep experimenting with the Pololu A-Star as a keyboard emulator for simple things, and stick with the Teensy for more complex things. I’ve also heard that the Teensy 2.0 will disappear in the future, which isn’t a huge deal, as the Teensy 3.1 is a big improvement over it, but the 3.1 does cost a bit more than the 2.0, so that’s one factor to consider when evaluating which board to use.

Have fun building your own keyboard!

Update #1: I’ve been talking to Pololu and they suggested the A-Star may actually be able to use the Teensyduino Keyboard libraries. I’m awaiting more info on this, as it would be an exciting development.

Update #2: It looks like the Teensyduino Keyboard libraries cannot be installed onto the A-Star, which is good to know. But don’t worry, I’ll be using the A-Star for some future projects anyway. ;)


Arduino for Beginners

It seems like just a week ago I mentioned a book, and it was, but here’s my confession: being a contributing photographer to a book is pretty simple. At least it has been in my experience. Writing a book is a huge beast, and while I did not take on such a herculean task, John Baichtal did, and somehow he convinced me to serve as the Technical Editor, and the result is Arduino for Beginners: Essential Skills Every Maker Needs.

The project took nearly a year, and my part consisted of getting chapters from John and checking everything for technical accuracy, and then passing them on to Rick at Pearson. Reading a book is one thing, but reading a book and closely examining everything in it for anything that may not be technically correct is another. I was also instructed to ignore any grammatical errors, which was hard for me, as I was only supposed to edit technical information. (Yes, there were a few typos. Just a few. ;)

Arduino for Beginners

My name is in print. I know, we’re in the future now, and dead trees are dead and what not, but I still like the fact that there’s ink on paper in a book and it’s got my name in it. Did I mention the entire process took about a year?

If you think this book would be useful for you or someone you know who is getting into using Arduinos, grab a copy from Amazon.

(Oh, and shortly after the book came out I was contacted about another book project, this one involving me writing the book, which I sadly declined. There’s just no way I’d have the time to do it right, and I didn’t want to give a partial effort to such a large project.)


Make: Lego and Arduino Projects

Leave it to me to forget things! I forgot to mention that my Arc-O-Matic was mentioned in the book Make: Lego and Arduino Projects. Get to chapter 3 and you’ll see one of my photos.

I should mention that I have not actually read the whole book, I ended up loaning it to someone who is way more into LEGO and Arduino stuff than I am, but if you want more info on it, WIRED has a nice write-up, and you can buy it from Amazon or directly from O’Reilly.

John Baichtal (one of the authors) has another book in the works which I’ll have a hand in, but we’ll save that story for another time.



The Beaver Dam Area Arts Association invited me to take part in a show titled “Beyond Your Imagination” which opens January 6, 2013 and runs through February 10, 2013.

So, you know, between the holidays, work, traveling, and other projects, I had to scramble to get Friday Night Drawbot and the Arc-O-Matic up and running again, with new code, and new parts, and create some art… with the help of robots.

So, consider yourself invited to the Seippel Homestead and Center for the Arts, 1605 North Spring Street, Beaver Dam, Wisconsin to view the show. If all goes well I will be there Sunday, January 13, 2013 for a live demonstration of the art robots.

Friday Night Drawbot

tl;dr: See robot art I created. With robots.

Update! Here’s a video of the bots in action.

Update! Here’s a photo from the show opening, courtesy of Jason Gullickson.


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