VFD Filament Driver Circuit

Don't give up! I spent the last 3 years troubleshooting this circuit with an LM4871 chip with the goal of supplying a low voltage alternating square wave current across the filament of vacuum fluorescent displays. Spoiler alert: it was the addition of a single 10Ω resistor to lower the voltage from ~5V down to ~3.3V.

Milling PCBs in the Classroom, Updated Workflow

I'm continuing to teach high schoolers to design their own circuit layouts and mill the boards so they can solder them together and have their own custom hardware to keep. The microcontroller I use for these is usually an ATTiny 85, 84, Adafruit Metro Mini, or Raspberry Pi Pico, all relatively inexpensive. What follows is an easier workflow than I've outlined in previous posts.

Arduino Controlled 5V Relay for Christmas Tree Lights

Our christmas tree lights plug into the wall behind the tree and are always hard to reach without sprinkling needles on the floor when we want to turn the lights on or off. This year I made an Arduino controlled relay that can turn the lights on and off with a switch that extends out next to the tree. Here is a video of the switch in action:

Hacked an Answering Machine

I found this old answering machine and originally thought it was a good find for just harvesting the 7-segment display. But as it sat around my work table it occurred to me it would be fun to use the display and buttons to insert a Simon game inside the case. I put it off because it seemed daunting but once I started on it yesterday it turned out to only take a day to put together.

Hacking Salvaged LED Displays (Part II)

Good news! I just found a discarded VCR with an LED display. That means it's time to salvage the display and make a project out of it. While the last post on 7-segment displays was a single digit, standard display, this one actually turns out to be 10-segment with non-numerical segments. So it will be an exercise in figuring out how a non-standard display works. In this post I will go over my process for hacking a display like this. If you're interested in doing this for a simple, standard 7-segment numerical display see this other post.

Hacking Salvaged LED Displays (Part 1)

You can buy many kinds of standard 7-segment displays, but I prefer hacking salvaged ones you can find in broken e-waste. True, it's easy to buy displays with integrated drivers that make them much easier to connect to a micro-controller and program, but more often than not I end up finding components and making up projects for them, rather than the other way around. In this post I'll show how I salvage a standard single digit 7-seg display, figure out the pinout, and make it do some fun things. In a following post I'll show how I do the same with a more complicated, non-standard, multi-digit salvaged display.

Teensy-Controlled Vacuum Fluorescent Display: Step-by-step

I'm recording in pictures the steps I'm taking to power and control this Yamaha Futaba vfd I removed from an old entertainment system.

Several Vacuum Fluorescent Displays

I have found, scavenged, and lit up four vacuum fluorescent display now, and look forward to many more. I find them beautiful both in the quality of their light and the complexity and fragile appearance of their circuitry.

Vacuum Fluorescent Display Adventures

I found an old 1986 microwave up the street to take apart. My favorite part to salvage from microwaves is the turntable motor but this one had a very special numerical display. I could see it wasn't your usual LED display but is encased in glass and filled with interesting metal plates and fine filaments.

Summer PD In Electronics

This summer I did some self-guided PD in basic electronics guided by my son's interest in learning about it. It has been a wonderful thing to do together, plus I've learned a ton. I probably would have covered what we did this summer in one week in Electronics 101 in college but the time has given us the opportunity to really let things sink in and follow up on our own questions. Here is the website that guided our experiments. This All About Circuits textbook written by Tony R. Kuphaldt explains things well but most importantly asks the learner to find their own resources for the experiments, which has been one of the most enlightening parts of the experience. Below I outline our activities and learnings, and some reflections.

Milling PCBs: Tinkercad Circuits, Eagle, Carbide Copper, and Carvey

This workflow for designing and milling a single-sided PCB on the Carvey CNC is an updated workflow from that which I worked out last year when I first started doing this in my high school classroom/maker space. This workflow is much simpler, and allows my students to make their own simple PCBs in less time and with less frustration, while still giving them an experience of circuit design, PCB layout, and hardware integration to container design.

Hacking IKEA LEDBERG flexible rgb lightstrip

I got a roll of awesome rgb lights at IKEA and used part of it to make an infinity mirror (sorry the link is to IKEA Europe but for some reason it's not on the US site, but anyway it was here in large quantities in Brooklyn). It's made to cut at certain points marked with a scissors and I only used a few feet of a 5 meter roll for the mirror project. So at the time I thought I would figure out eventually how to use the rest. It would be a shame to throw away.

16 X 32 LED Matrix USB > serial adapter driver

Just putting this here.
To communicate with this 16 X 32 LED matrix I use this FT232 Serial Module FTDI-Compatible Helper, which requires this Silabs driver.

Daisy Chained MAX7219 Led Drivers

This project builds off of some work I did earlier with the MAX7219 led driver running a single 8X8 led matrix. Now I'm getting two of them daisy chained and driving 2 matrices. I'm moving the project off the breadboard and onto a perfboard, as well. This post has great instructions for wiring one driver and led matrix, which I've gone back to again and again.

One MAX7219 soldered and connected, running a random worm program. The second driver out in front isn't connected yet.

Stepper Motor Player

I took some stepper motors out of some old printers to play with. Newer printers seem to use DC motors, but I love finding steppers because they make such nice sounds. I spent a while on this project just figuring out how to get the steppers to work and some different options for

Animate Stories With Neopixel Ring and LightLogo

I've been trying out the Neopixel Ring-24, a ring of 24 RGB LEDs easy to plug in to an Arduino. Instead of using the Adafruit neopixel Arduino library I'm beta-testing LightLogo, a new IDE for the Neopixel and Arduino to write programs in Logo. This can make a really beautiful device with its rich colors more accessible to younger

LED Handbell Gloves

This project was quite long in development, more than a year, in fact! I learned a lot about technology design so the process is worth recounting. Two then-juniors I taught in a robotics class, Susannah and Nicki, now graduated, asked me for help with an idea they had. They were members of a handbell group they had played with for 5 years and wanted to make handbell gloves that light up each time they play a bell, unveiling the gloves for one piece in their final concert. We batted around some ideas. They thought about using a Lilypad Arduino and an accelerometer but I thought we

A Machine Asking To Be Remade

I've been having a great time teaching students about 3D design and printing, and helping them print things they need. From robot scoops to ears, it's always an exciting surprise to find out when the printer can be a useful tool for learning. One of the more interesting ways it serves as a useful tool is in printing parts for itself. I've found two of these opportunities so far. Early on I could see that the filament tube on the Replicator 2 came out of its clips on the back easily when the extruder had to move towards the back of the build plate. I found a filament tube upgrade on Thingiverse that has worked perfectly.

Our @makerbot printed a part for itself! An upgraded filament guide. pic.twitter.com/TCKS2JbQXE
— Erik Nauman (@openblackboard) February 10, 2014

Then recently a student's dad brought in a few spools of filament to provide more colors for printing. One of the spools has a much smaller hole than the standard Makerbot spools. So I found a spindle, again on Thingiverse, modified it a bit in Tinkercad, and now the spool fits perfectly.

Build Your Own Computer

It's been a long time since I've written anything for no particular reason but being busy. But I recently had 20 high school girls in a class doing something I have to write about. As part of a day full of STEM activities in our high school I had a bunch of girls put together some old PC desktops we were planning to put out to pasture. It was a morning full of anticipation, exploration, frustration, and finally, pure exaltation. I provided scaffolding in the form of a Prezi they could explore  as they needed, gave them screw drivers, and pointed them towards the pile of parts. The best moments were booting up. With some false starts and reseated processors the Dell and Windows splashes started appearing on screens around the room and the girls yelled for joy. They were so excited and proud of their work.

Exciting Developments with Microsoft Kinect

I'm much more excited about what people are doing with Kinect than what Kinect is made to do out of the box, no matter how Microsoft feels about it. There are some great developments, and so quickly!

• Shadow puppet 
• iRobot
• Ahhh, here's a collection
• And the motherlode

And to think after I showed my students a couple early hacks they wondered why you would want to do that...