At the bi-weekly meeting tonight, as promised, I brought my non-working circuit, and as promised, Paul helped me get it working. It is a circuit that allows current to flow through a p-channel mosfet (http://www.fairchildsemi.com/ds/FQ/FQP47P06.pdf) from a power supply to a 12V sealed lead-acid battery and a load (which draws about 120 mA, normally), but that prevents current from flowing from the battery back into the power supply. The idea is to use an op-amp to compare the voltages upstream and downstream of the mo
Portland CORE effigy at Burning Man will be using DMX controlled lighting this year. At least that's the plan, but a low-cost and low-power way to automatically play the lighting sequence (without a PC) is needed. Here's a little board I made for the purpose.
Click "Read more" for source code and other technical details.
Recently I've put a lot of work into improving USB virtual serial receive speed. Here's a detailed article with complete source code for the benchmarks.
Click "Read more" for the Arduino code and details....
David's puzzle on April 6th was a lot of fun to work with. If you want to see my answer, read the first few pages of:
Many factors helped birth the HypnoLamp: At Toorcamp 2012, I learned to program microcontrollers. Jeff of OlyMEGA blessed me with addressable LED strips, at the aforementioned event. Jeff was also at the Portland Mini Maker Faire, showcasing (among other things) glass Ikea lamps with LEDs inside. I decided to build my own version!
Here's some details of my radio spectrum analyzer hack at Maker Faire. But first, a quick video of the hack in action:
The Dorkbot booth at Maker Faire worked out really well. Here's a couple good photos Zach took:
This is the right-hand side, with my extremely bright OctoWS2811 Arduino library demo triggered by stomp pads.
This is the center with Tom's Bee counter, Zach's Hypnolamp, and Tara's soldering demo in the center, viewed over the top of Jared's VFD display spectrum analyzer (and FPGA Robotron not visisble in this photo).
Click "Read more" for more pictures, source code and other stuff
The Arduino IDE editor's lack of support for X11's select-paste mechanism has always annoyed me. Well, I finally got around to adding it. Especially for helping people with their Arduino troubles (which I do every day), it's so very nice to finally be able to quickly select-paste between Arduino and forum messages, email, terminal windows, etc.
This is a Unix/X11 feature. Mac & Windows do not have anything similar. But on Linux it's so very fast and convenient. This tiny little feature really makes me happy. :-)
Update: Arduino 1.0.5 now has this feature on Linux. It's not mentioned in the release notes, but if you try select-paste, it now works properly even without installing Teensyduino.
Over the last couple weeks I've been working on a automated test system for Teensyduino, which someday will verify nearly all the Arduino functionality on every board and also test most of the Arduino libraries. Here's what my first try looks like.
Click "Read more" for another photo, a bit of discussion about how this works (and what doesn't work so well), and a peek at what will be my second attempt.