Archive for category: electronics

Musing about a 2 dimensional delta robot…

February 2, 2017 | electronics, Embedded, My Projects | By: Mark VandeWettering

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 1K code challenge, which you can see on my page, and which hopefully I’ll write […]

Weekend Update: Maker Faire, new gadgets, and I ground myself…

May 17, 2015 | Arduino, electronics, ESP8266, WSPR | By: Mark VandeWettering

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 […]

Making a simple RC switch…

June 14, 2014 | electronics, LED, My Projects | By: Mark VandeWettering

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 […]

A day at the Official Propeller Conference

May 5, 2013 | electronics, Microcontrollers | By: Mark VandeWettering

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 […]

Simulation experiments with LT-Spice…

January 20, 2013 | electronics, Homebrew CPU | By: Mark VandeWettering

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 […]

Tiny-Tim: A DTL computer (in progress)

January 20, 2013 | electronics, Hardware, Homebrew CPU, Homebuilt CPUs | By: Mark VandeWettering

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 […]

Examining the output of a simple remote-keyless-entry transmitter…

February 20, 2012 | Amateur Radio, Arduino, electronics | By: Mark VandeWettering

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: […]

Spray-on Antennas? I say “Spray-on Bunkum”

February 17, 2012 | Amateur Radio, electronics, Rants and Raves | By: Mark VandeWettering

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 […]

More on ATtiny programming…

February 15, 2012 | Arduino, electronics | By: Mark VandeWettering

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 […]

Web-based control of an RGB LED via the Nanode, an Arduino compatible microcontroller

February 12, 2012 | Arduino, electronics | By: Mark VandeWettering

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 […]

A $.33 MAX232CPE, or a $0.01 2N3904?

January 28, 2012 | Arduino, electronics | By: Mark VandeWettering

In response to my previous post, @xek replied: @brainwagon has anyone suggested the stupid bjt inverting “buffer” trick? 1/28/2012 7:04 pm via TweetCaster for AndroidReplyRetweetFavorite @xek Josh Myer 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 […]

Unequal Resistor R-2R Ladder Optimizer

January 26, 2012 | electronics | By: Mark VandeWettering

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 […]

New 6502 processor at

January 26, 2012 | electronics | By: Mark VandeWettering

Dave Jones (@eevblog) tweeted: The 6502 is back: 1/26/2012 6:40 am via TweetDeckReplyRetweetFavorite @eevblog Dave Jones And indeed, he’s right! WDC (the Western Design Center) has made a new version of the 6502 available at It’s a 40 pin DIP package, listed at $6.95 in quantity one, and can be clocked up to […]

New addition to the brainwagon lab: a Rigol DS1102E

January 22, 2012 | electronics | By: Mark VandeWettering

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 […]

Interesting discovery regarding a junkbox piezo element…

January 21, 2012 | electronics | By: Mark VandeWettering

I was tinkering with a small electronics project (article and video to come) and needed a sound output. Digging around in my junkbox, I found one of these piezo speakers, and decided to use it, driving it with a square wave from my Arduino: Piezo Element 1500-3000Hz – My initial test was supposed to […]