BezBlog

This is my third post in a series about the open source split-flap display I’ve been designing in my free time. I’ll hopefully write a bit more about the overall design process in the future, but for now wanted to start with some fairly technical posts about build automation on that project. Posts in the series: Scripting KiCad Pcbnew exports Automated KiCad, OpenSCAD rendering using Travis CI Using UI automation to export KiCad schematics OpenSCAD Rendering Tricks, Part 1: Animated GIF OpenSCAD Rendering Tricks, Part 2: Laser Cutting OpenSCAD Rendering Tricks, Part 3: Web viewer Since I’ve been designing the split-flap display as an open source project, I wanted to make sure that all of the different components were easily accessible and visible for someone new or just browsing the project. Today’s post continues the series on automatically rendering images to include in the project’s README, but this time we go beyond simple programmatic bindings to get what we want: the...

This is my second post in a series about the open source split-flap display I’ve been designing in my free time. I’ll hopefully write a bit more about the overall design process in the future, but for now wanted to start with some fairly technical posts about build automation on that project. Posts in the series: Scripting KiCad Pcbnew exports Automated KiCad, OpenSCAD rendering using Travis CI Using UI automation to export KiCad schematics OpenSCAD Rendering Tricks, Part 1: Animated GIF OpenSCAD Rendering Tricks, Part 2: Laser Cutting OpenSCAD Rendering Tricks, Part 3: Web viewer In my last post , I discussed how I scripted the export of 2d renderings of the custom PCB. In this post, I’ll cover how I hooked up that script and others to run automatically on every commit using Travis CI, with automated deployments to S3 to keep all the renderings in the README updated, like this one: I'll talk about this particular animated OpenSCAD rendering in a future blog post ...

This is my first post in a series about the  open source split-flap display  I’ve been designing in my free time. Check out a  video of the prototype . Posts in the series: Scripting KiCad Pcbnew exports Automated KiCad, OpenSCAD rendering using Travis CI Using UI automation to export KiCad schematics OpenSCAD Rendering Tricks, Part 1: Animated GIF OpenSCAD Rendering Tricks, Part 2: Laser Cutting OpenSCAD Rendering Tricks, Part 3: Web viewer For the past few months I’ve been designing an open source split-flap display in my free time — the kind of retro electromechanical display that used to be in airports and train stations before LEDs and LCDs took over and makes that distinctive “tick tick tick tick” sound as the letters and numbers flip into place. I designed the electronics in KiCad, and one of the things I wanted to do was include a nice picture of the current state of the custom PCB design in the project’s README file. Of course, I could generate a sn...

After fixing my pinout mixup from the previous version, my Simple USB LED Controller (SULC) v0.2 works! Check out Part 1 and Part 1.5 for a bit more background on SULC.  In short, it's a ridiculously simple way to control high-power RGB LEDs from a computer.  You can send commands like "red, blue" or "all green" to control the LEDs, rather than implementing some complex protocol. The build process for this version was the same as my first prototype - using a laser-cut solder paste stencil and "frying pan" reflow soldering - so I don't have any new pictures to show of that.  However, I do have pictures and video of the new version in action: (I ran out of TLC5940s, so I decided to make this board with just 2 of them rather than waiting for a shipment to arrive - notice the missing IC in the top right corner) The video gives a brief overview and shows just how easy it is to control high-power LEDs with SULC: The full de...

I just got some PCBs in the mail!  These are the PCBs I designed for Next Make's Campus Preview Weekend (CPW) event later this April.  CPW is when all the MIT admitted students are invited to come check out the campus and see what life at MIT is like.  Generally all the student groups on campus throw fun events for the prefrosh - and Next Make is no exception! This year, prospective students of the class of 2016 will be able to solder up and take home a cute USB gadget at the Next Make event: The board plugs into a usb port and pretends to be a usb keyboard - it can then "type" a message into the computer it's plugged into, without having to install any drivers (inspired by an Instructable  USB PCB business card  that types out a guy's resume).  You can program any message you want into it (up to about 1000 characters).  Here's a video of it in action: The board is based on the ATTiny45 with  V-USB  (software USB...

I've been working on a simple usb led controller  (read  Part 1 ), but unfortunately ran into a bit a of snag - it turns out that the surface-mount package of the TLC5940 has different pin assignments than the through-hole version I've used before - even though it has the same number of pins in the same physical arrangement, the pin assignments are shifted over by 7 pins, which means my original PCB designs don't work.  Lesson learned: double check the datasheet!  I've updated the PCB design and sent off v0.2 to have new PCBs made, so now I just have to wait a few weeks for them to arrive. In the meantime though, I was able to get the LUFA usb library up and running, port the Arduino TLC5940 library to work on the ATMega32U2, and get a good portion of the led controlling firmware written.  In order to test this out, I programmed the controller board I built, but had to use led drivers on a separate breadboard.  It's ugly, but it works: The goal o...

Back when Next Make built the Next House Party Lighting System , we designed the LED controllers to connect on a shared RS-485 network over CAT5 cable.  This was a great solution for that system since the controllers were far apart (RS-485 uses differential signaling so it's pretty robust over longer distances), and we had 24 separate controllers to connect so we wanted to be able to chain them together on a single network. But if you wanted to set up a smaller scale LED system with just 1 or 2 sets of LEDs, those controllers were a bit overkill - you needed a separate USB->RS-485 converter and then had to string them together with CAT5.  So I set out to design a simpler high power LED controller that had a USB port directly on it (I'm calling it  SULC - the Simple USB LED Controller ). Instead of using an FTDI (USB->serial converter IC) along with a microcontroller, I wanted to try out the ATMega8/16/32U2 family of AVRs which has USB support built-in.  Un...