brainwagon

The ESP8266 is an amazing little processor: cheap and capable and (most interestingly) WiFi enabled. I have some of the older “nodemcu” boards that I got for about $7 each, but there are newer alternatives that include up to 4M of flash memory, and a variety of interesting form factors. I noticed that WeMos was […]

Ken Boak had mentioned on twitter that someone was creating a blinken-lights front end for the simh simulator of the PDP-8, called the PiDP-8, since you can power the entire thing from a Raspberry Pi. Very cool, but not quite available yet. What was available from Oscar is the Kim-Uno, a simulator for the old […]

If you follow me on twitter (@brainwagon) you’ve undoubtedly seen a few mysteriously short tweets about experiments I’ve been performing on magnetometers. It’s hard to give any meaningful context in just 140 characters, so I thought I would dump a short overview of what I’m doing here, in the hope that I’ll turn it into […]

Yesterday I just had a few minutes to hack around, and I decided to marry a sketch that used the TinyGPS++ library to the clock display that I had working the other day. I’ve been hopping back and forth between the Arduino and the Teensy LC as a development platform. Since I still had the […]

In a previous post, I wrote some interrupt driven code to refresh a multiplexed 8 digit, 7 segment display. Every 2 milliseconds, the Arduino triggers an interrupt, and then clocks out sixteen bits to a pair of chained 74HC595 shift registers, and then returns. That displays a single digit. The next interrupt displays the next […]

A couple of days ago, I wrote about experimenting with a little Chinese 8 digit, 7 segment LED module that is driven by some 74HC595 shift registers. My initial experiment in driving it with the Teensy was successful: I got a nice, steady display with a simple interrupt driven scheme which displays each digit for […]

A few weeks ago, I was scanning the Deal Extreme website, and ordered a few different LED displays, not because of any pressing need, but because I wanted to have some display options available if I needed some for a project. I was especially interested in cheap LED displays. One of the ones I ordered […]

I was working on some additional software to power my nascent WSPR project. I’ve been thinking that rather than using an Arduino, it would be better to use the Teensy, so I’ve been experimenting a lot with the Teensy LC. My idea was to wire up my Ultimate GPS and an I2C based DS3231, and […]

Yesterday, I got a small 4 digit, 7 segment LED display board in the mail from dx.com. Cost was around $3 shipped, and the module uses a 4 pin interface (power, ground, clock and data). Originally, I thought it was I2C, but like other modules I have received based upon chipsets made by Titan Micro […]

Previously, I wrote about a project I called the Big Box O’ RF. I’ve shifted goals a bit, and done some experimentation, and have changed some of my goals and approach. First of all, I’ve changed the goal a bit. Instead of being a piece of test equipment, I’m actually more interested in using it […]

One of the things that I really like about the Teensy LC (besides its low price) is that it has three hardware serial ports. Hardware serial ports are just nicer than the SoftwareSerial ports that you see on the ordinary Arduino platform. While the latest support for SoftwareSerial ports on digital pins work reasonably well […]

I hooked up my new DS3231 clock module to an Arduino that was being fed with the one pulse per second input from a locked GPS, and counted the number of pulses from each. In 3170 seconds, the clock module generated 103874565 pulses, for an average pulse per second of 32768.0015773 pulses per second. That’s […]

As I mentioned in a previous post, I was not enormously satisfied with the accuracy of the DS1307 clock module that I got from China. It was hard to argue with the less than three dollar price tag, but I was hoping that the accuracy might achieve 20ppm (less than two seconds of drift per […]

My tinkering with using the Adafruit GPS as a time base has yielded some results. I’m still getting a few spurious interrupts when I feed my buffered PPS signal into the interrupt pin on the Arduino, but they are relatively few and far between (and quite regular in appearance). A few short notes, followed by […]

Greetings readers. I’m hopefully wishing there is still more than one. This weekend was the Bay Area Maker Faire 2015, the 10th incarnation of an event which has become increasingly (even frighteningly) popular. I’m tempted to channel Yogi Berra, who said “Nobody goes there. It’s way too crowded.” Anyway, I got out of my house […]