brainwagon

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 […]

I’ve often thought that creating a replica of an early Baird mechanical television, or televisor would be a fun project. But when starting, you immediately run into the problem of how to generate material for them. The Narrow Band Television Association standard format specifies 32 line format at 12.5 frames per second (400 lines per […]

While researching something completely different, I found Adrian Freed’s very cool page with code to generate high quality sine waves using PWM on the Arduino. This code could serve as an audio frequency signal generator, or as the basis of a computer music project. It also demonstrates some non-trivial Arduino wizardry in dealing with PWM […]

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 […]

I’ve been trying to do a bit more Arduino programming and interfacing lately. Nothing too difficult, but just trying to expand my junkbox and my skills so that I can quickly prototype new ideas and expand the kind of projects that I can tackle in the limited time that I seem to have for playing […]

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 – RadioShack.com My initial test was supposed to […]

I share an interest in old computing technology with several of my friends and readers. An interesting sub-topic within this vast area is the world of computers based upon relays. In the last couple of days, I found cool links to two different relay based computing projects, so I thought I’d pass them along. First […]

This is just a plug for a cute little pair of gadgets that I got the other day.. If you are like me and use solderless breadboards to experiment with stuff on the Arduino, you end up with the Arduino and the breadboard connected by a hodge podge of wires, and if you accidently tug […]

We’ve all heard it (and most of us have said it): “X is just a dumbed down for the masses.” Heck, I came dangerously close to saying it myself in today’s earlier rant. But I didn’t say it, and I try not to, because I think it’s not really very useful. First of all, if […]

First of all, I really like the Arduino. There are lots of reasons: great community, relatively inexpensive, wide hardware availability and variety, and often a good “impedance” match to projects. But there are a few design choices (both hardware and software) that can be a nuisance, especially as you try to push the limits of […]

Update: Welcome Hack-a-day readers! If you are looking for the schematics for this “transmitter” (really just a simple oscillator, send some love to radio guru Steve Weber over at his website. You could really use any oscillator you like, even a canned oscillator (although the square waves would generate lots of harmonics). Yesterday’s project coupled […]

Before toddling off to bed last night, I did a bit more tinkering, and a bit of thinking, and then a bit of research. The YouTube video I made showed that the spurious radiation from just attaching a clip lead from the oscillator to my oscilloscope gave enough signal to inject itself into my RFSpace […]

My G0UPL QRSS beacon is working pretty well, but is only putting out about 40mw of power, when it probably should be putting out 100mw. I was pondering oscillators in general, and (as I do often) surf for information and inspiration. I found both on Steve “Melt Solder” Weber’s website, in the form of a […]

I’m beginning to correct some of my misunderstandings re: JFETs and for some reason, oscillators are beginning to become something that I think of as interesting, particularly at very low voltages. Without comment, and for future perusal, I just present this cool link, which shows oscillators which can run on very low voltages (just a […]