Stenciling PCBs on my desk

I try to assemble as many Rascal Micro products as I can myself here in Somerville. The Rascal itself has a ball-grid array processor, which is really hard to assemble reliably by hand, but simpler stuff I can handle. For my Precision Voltage Shield, I assembled the first one by…

Announcing Rascal 2

The Rascal has been a steady seller over the last 2 years, but it's time for a hardware upgrade! Same philosophy, more reach When I designed the original Rascal in 2010-11, the explosion of small ARM Linux boards (Raspberry Pi, Beaglebone, and the like) hadn't happened yet, and there were…

Logging science in less than a second

As the Rascal has matured over the last few years, I've started to think about how it can change the working lives of artists and scientists. The Rascal is already a useful tool for people who have some experience with web programming and basic electronics, but I'd like to see…

The Raspberry Pi vs the Rascal

When I talk to people about the Rascal, they often ask about the differences between a Raspberry Pi and a Rascal. Summary: if you want the cheapest possible computer, buy a Raspberry Pi. If you want to control some Arduino-style hardware from your web browser and you're a busy person…

The Slingshot, a realtime coprocessor for the Rascal

This post is to preview some of the stuff that I've been working on for the Rascal. Suppose you want to build a pulse counter so you can tell how fast a motor is spinning. The pulses are coming out of the motor at around 10 kHz, i.e. at…

Reading 125 kHz RFID cards using Wiegand protocol in Python

One of the early Rascal customers was the Massachusetts General Hospital Learning Lab. The Learning Lab has been developing an attendance tracking system using 125 kHz RFID cards. In their current system, each card reader talks to an Arduino microcontroller using the Wiegand protocol; the Arduino talks to a PC…