brainwagon

My electronics experimentation has brought a couple of comments from people I’ve met who have much greater experience and knowledge than I. For instance, in response to my posting of a schematic for flashing a rather large, powerful LED yesterday, I drew the attention of Mike Colishaw on Twitter: https://twitter.com/#!/MikeCowlishaw/status/129464059937554432 And of course, Mike is […]

Nothing is quite so humbling as someone coming in and showing you that you are making your problem way more complicated than it really is. Lee pointed out that I was overthinking it: that a simple 2N2222 would work just fine, and indeed, I went back over it, and realized he was right. I entered […]

This posting begins with a caveat: while I’m pretty experienced as a programmer and software engineer, I’m actually a bit of newbie when it comes to electronics. I’m entirely self-taught, and because of my inherent laziness, I find it hard to learn anything before I actually need to know it. This means that I often […]

The great thing about doing a real project like my satellite tracker is that it makes you learn a lot, in a whole lot of different areas. In other words, it’s good exercise! And thus, it is good when you discover something doesn’t quite work right: you have another opportunity to learn. Well, today, something […]

Another cool link in my blog searching: constructing speakers out of paper and strips of copper foil. High-Low Tech – Paper Speakers.

I’ve always been fascinated by emulation and virtual machines, as well as retro-computing: resurrecting the old machines of my past. I never owned an old CP/M machine, but there are still some neat projects where people construct there own, and simulators like SIMH and YAZE-AG are good software simulators. But what I always wondered was […]

No commentary, I just found a reference to this module in this cool article on making a VGA scoreboard. The author intends to send information to an AVR using this module, and the price and capability seems pretty good. Wireless Bluetooth RS232 TTL Transceiver Module – Free Shipping – DealExtreme.

This is awesome! MIT has created an interesting course as part of the their Open Course Ware project: it describes how radar can work, and as a final project, students were expected to build an test a simple radar system. Their description: Are you interested in building and testing your own imaging radar system? MIT […]

A couple of months ago, Collin’s Lab featured a story about making your own piezoelectric crystals from Rochelle salt. Collin stopped short of making an actual microphone though: he just demonstrated that the salt crystal would generate a series of voltage spikes when whacked with the handle of a screwdriver. Leafcutter John followed pretty much […]

A couple of weeks ago, I programmed an Arduino to take digitized sound stored in its rom, and send it out via PWM of an LED. A couple days after that, I used the same code to send voice using a small 5mw laser module. Ever since then, I thought it would be good to […]

Scott Harden had a very cool idea: sending Hellschreiber, an old fax-like teleprinter code invented by Rudolf Hell, using just an Atmel ATMega48 and a canned oscillator. The idea is pretty simple: the canned oscillator will produce a square wave with the same amplitude as the input voltage. So, you simply power the oscillator with […]

I hadn’t worked through the biasing calculations for collector feedback common emitter amplifiers before, so I thought I’d do that for the simple one transistor NPN preamp that Dino built as his weeklyhack. But even before I got to it, I was confused by something. Check out the schematic (cribbed from Dino’s post): I was […]

I was looking for some amplifier references to brush up on amplifier design. I found this one to be pretty good: Amplifier Tutorial.

A few weeks ago I did an experiment that stored an 8 bit PCM file in the flash memory of an Arduino, and then used PWM to flash a laser at a high rate so I could transmit that audio over a long distance to a solar cell based receiver. A few days ago, I […]

Yesterday, I wrote about soldering together my bliplace kit. Today, I thought I’d have a peek at the code and the schematic. Here’s the schematic: Not much there, but a couple of interesting things. The microphone is an electret, which needs some power to be functional (supplied through the 10K RU resistor). To me, the […]