Fun With Reuleaux Triangles
Math Monday came early this week, and we had some fun exploring Reuleaux triangles. Next to a circle, they’re the simplest curve of constant width you can make — that basically means you can roll a plank on top of…
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Reader-built Chess Boards
I love getting photos of chess and checker boards that people have built using my tutorial (), or after being inspired by it, and so I’ve decided to start asking permission to post those photos and the stories behind them…
Arduino-compatible GI-SP0256-AL2 Speech Synthesizer
Here’s an Arduino-compatible GI-SP0256-AL2 speech synthesizer module that I’m finishing up. It’s a great 1980’s-era allophone speech synthesizer chip that was used in Intellivision expansion modules and sold at RadioShack stores for years for about $12. You can still find…
StickBot V2.0 – Untethered!
We finished up PopsicleBot StickBot with a couple of 555 timer circuits to allow it to roam freely and untethered. It was a lot of fun to build, and even though it’s not the fastest walker or the simplest design, it…
DMD: Dual Motor Doohickey (Modular RBBB and TB6612FNG Driver Board)
Here’s a small, inexpensive, modular, and easy-to-customize motor controller I’m working on that incorporates the Modern Device RBBB ($13), and Pololu’s TB6612FNG Dual Motor Driver Carrier ($8.50). If I fry or want to retask the brain or the driver or…
Parsing and Joining on a Long Text Field Using SQL
Here’s a little SQL gymnastics used to parse and query against a predictably-formatted long text field. The challenge: We have a single text field that contains a list person_id-to-area mappings, and we need the query the database for a list…
StickBot: A Simple 6-Legged Walker
The goal was to crawl on the cheap, and what’s cheaper than popsicle sticks craft sticks and fishing line? Next we’ll wire up a 555 circuit so it can roam untethered, but until then, here’s how to make one of your…
Animated History of the United States of America
In celebration of Independence Day here in the United States of America, here’s a great 10-minute narrated animation that reviews how the nation got to where it is today. Read the instructions, click the X, then click Play. Videos…
Convert a Computer Power Supply into a Benchtop Supply
Here’s a great video from Phil Levchenko over at Jumper One that explains how to convert a computer ATX power supply into a bench-top power supply. I’ve had an older ATX supply by my desk here for the past couple…
Kilburn Highest Factor Routine in C#
To mark the 63rd anniversary of the first stored computer program to run (June 21), I rewrote the original code in C# last night, both using the original algorithm (that was never intended to be efficient) and using a more…