Here’s a 12-channel bidirectional logic level shifter with a 3.3V power regulator that I designed so I could easily interface 5V circuits with cool 3.3V widgets like the ADXL345 accelerometer, the NRF24L01+ wireless transceiver, and the Nokia 5110 84×48 LCD. For the…
I used the excellent Quick KICAD Library Component Builder recently to build a new component for eeschema in KiCAD, but when I imported the library, I got an error dialog that said, “Library component load error error <error <pin only…
Before I placed my order, I had questions about Seeed Studio Fusion PCB service turn-around time for shipping to the USA, and so I figure others might as well. Here are details of my order of the ten 5cm square…
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…
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…
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…
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…
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…
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…
Modern Device offers a couple of fantastic, low-cost, bare-bones Arduino-compatible boards and kits, called the BBB (Bare Bones Board) and the RBBB (Really Bare Bones Board). The BBB is larger (yet still 1/3 smaller than the ArduinoDuemilanove), and the RBBB is…