brainwagon

Yes, it’s me, back after a far too long hiatus. Sometimes life intervenes, and you just have to reset your priorities. But rest assured, the geeky stuff that I used to work on and chronicle in my blog continues, and on this long Labor Day weekend, I thought I might mention a project I’ve been […]

First of all, if anyone is still swinging by this blog, yes, I’m still alive. While I haven’t exactly been prolific in my leisure activities, they haven’t stopped entirely. I worked on some simple embedded development for the hackaday.io 1K code challenge, which you can see on my hackaday.io page, and which hopefully I’ll write […]

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 […]

Over the last couple of years, I’ve spent a little bit of time making fixed wing aircraft from Dollar Tree foam. The results have been interesting and fun, but I’ve found that the need to find relatively large areas to fly means that it’s harder to go fly than I would like. On the other […]

Even casual readers of this blog know that I’ve enjoyed playing around with the Arduino and the Atmel AVR chips. I really like them, and have used them for a variety of personal projects, as well as using them for a variety of educational projects for a local high school where I mentor students. But […]

Yesterday, I mentioned Rory’s excellent introduction and exploration into DTL logic. He covers some of the basics here, including circuits for all the basic gates: AND, OR, NOT and NAND. The AND and OR gates are interesting, because they consist entirely of diodes and resistors. They do have the drawback that they are “lossy” (the […]

Previously, I had linked to Rory Mangles’ experiments with relay based computers. He had an incredible build of a relay logic computer called Tiny-8 which used paper as program mamory, inked with a pattern which could be read by photo sensors to sequence the control logic in his computer. I thought it was amazing. But […]

Yesterday I was looking (sadly unsuccessfully) for some BPW32 photodiodes that I know I have somewhere, when I ran across some of 434 Mhz transmitter modules from Sparkfun (now a retired part) that I had never used. These little $4 transmitters are commonly used for remote-keyless access or similar applications. They have just four pins: […]

Thanks to John, who pointed out that this post was mangled. Fixed now. I wasn’t going to mention this one, but Dave, Chris and Jeff over at The Amp Hour brought it up on their most recent podcast, but other than Jeff’s somewhat enthusiastic declaration that he thought it was BS, I don’t think they […]

Last night’s hacking adventure was inspired by a couple of recent posts from Roger, G3XBM having to do with light based communication. The first was his simple beacon design: it’s just a keyer chip, a MOSFET, a voltage regulator, and some (beefy) current limiting resistors. Roger used this beacon to do some non-line-of-sight communications via […]

Okay, I finally got some time to record a video about a simple little webserver project I hacked together earlier this week. My wife Carmen got me a Nanode kit from Wicked Device around Christmas. These are Arduino compatible development boards which include a Microchip ENC28J60 Ethernet device to enable web connectivity. One slight drawback […]

In response to my previous post, @xek replied: https://twitter.com/#!/xek/status/163442298456260608 Well, the fact is I had heard of doing that. It’s not really hard to rig something that will convert the RS232 level from the GPS into TTL levels for the Arduino. It just takes a single transistor inverter: you rig an 10K resistor from the […]

I was reading up on resistor ladder DAC circuits on Wikipedia, and came across the Unequal Resistor R-2R Ladder Optimizer. It’s very neat! You can enter the number of bits you need, and the values of the pile of resistors that you have measured from your bench, and it will produce an optimized design using […]

Dave Jones (@eevblog) tweeted: https://twitter.com/#!/eevblog/status/162530266513014784 And indeed, he’s right! WDC (the Western Design Center) has made a new version of the 6502 available at mouser.com. It’s a 40 pin DIP package, listed at $6.95 in quantity one, and can be clocked up to 14Mhz. It sends my mind racing back to the days of Star […]

This week, I splurged and bought myself a new piece of test equipment: a Rigol DS1102E 100Mhz oscilloscope, and compared to my old 25Mhz Philips (which was indeed a great buy at only $20) it’s very, very cool. Among the most neat features that I’ve started to use is the ability to do screen and […]