Quick: which pins are used for I2C on an ATmega168 microcontroller?
If you’re a true alpha geek you probably already know the answer. For the rest of us, ChipDB is the greatest thing since the resistor color code cheat sheet. It’s an online database of component pinouts: common Atmel microcontrollers, the peripheral ICs sold by SparkFun, and most of the 4000, 7400 and LMxxx series parts.
The streamlined interface, reminiscent of Google, returns just the essential information much quicker than rummaging through PDF datasheets (which can also be downloaded there if you need them). And the output, being based on simple text and CSS, renders quite well on any device, even a dinky smartphone screen.
Site developer [Matt Sarnoff] summarizes and calls upon the hacking community to help expand the database:
“The goal of my site isn’t to be some comprehensive database like Octopart; just a quick reference for the chips most commonly used by hobbyists. However, entries still have to be copied in manually. If anyone’s interested in adding their favorite chips, they can request a free account and use the (very primitive at this point) part editor. Submissions are currently moderated, since this is an alpha-stage project.”
[Cliff Miller] pointed out this incredible project from 2004. [John Pultorak]’s journey began in late 2000 when he decided to build a 60’s or 70’s era minicomputer. While gathering technical documentation, he found some interesting information on the Apollo Guidance Computer and felt that was the way to go. The AGC was the first integrated circuit computer ever built. Designed by MIT in 1964 it was constructed from ~5000 ICs, almost all 3-input NOR gates. [John]’s version uses late 1960’s 74LS TTL logic which gains him a 10 to 1 reduction in the number of ICs. A good thing when you have to do ~15K wirewrap connections. He also used flipflops and register chips instead of building everything from NOR gates. [John] essentially built the AGC three times: First, he coded a simulator in C++. Then, he imported the logic design into CircuitMaker to verify that it would actually work. Finally, he built the 3 by 5foot machine. He’s provided an amazing amount of documentation for anyone that wants to explore this device and the overview alone is well worth a look.
Sparkfun has recently released a bevy of new boards and other devices, with some very intriguing new builds among them.
The first board that caught our attention is the Wee. It is a compact Arduino compatible controller that features a small size, low voltage, and many other minimalist attributes. It is built around an ATMega 168V and uses all SMD parts.
For even tinier fun, check out the LilyPad LED. It is a LED designed to be incorporated into clothing, featuring large holes for threading, a thin and extremely small PCB and a very bright 250mcd light. It is also washable, meaning that one or many can permanently be incorporated into clothing without fear of losing them. You can see these in the turn signal jacket we covered earlier.
The last one we’ll discuss is the LiPoly Charger, a USB lithium ion battery charger. Based on the Max 1555 IC, the LiPoly can use USB bus power or a 2.1mm center positive wallwart power(it uses the more high-powered wall-wart if both are connected). It can’t charge NiMH batteries, but it is still compact, efficient, and very useful.