Those who are familiar with Atmel’s line of 8-bit AVR microcontrollers should already know that some of them have support for external RAM. But have you ever actually used this feature? We haven’t. Now you can learn how it’s done by reading through this guide. It touches on all of the hardware, but doesn’t dwell on it. Instead, you’ll get the background you need on how to write to, read from, and test an external module like the one sticking up in the image above. The test routine shows how to make sure everything’s working correctly with your memory mapping before you begin developing firmware around this increased capacity.
Okay, this may not be saving any lives, but it makes for a fun novelty at your next rager. Most Breathalyzers aim to keep you from driving when you’ve had too many. The Squidalyzer encourages party-goers to drink more and more by treating a high blood-alcohol-content with great fanfare. An Arduino, a gas sensor, and Processing all come together for this hack. A television interface tells you when to blow into a cup which houses the sensor, and gives a reading of what it measures. Blow higher than the last guy and you’ll break the record. Watch the demo after the break to see the fun [Geoff] had with it. And remember, friends don’t let friends solder drunk.
Continue reading “DIY Breathalyzer may be the hit of the party”
These calculators are networked together, able to pass information and play games on a multi-screen playing field. All of this is thanks to [Christopher Mitchell’s] work on a package called CalcNet. This networking software takes advantage of [Christopher’s] shell and GUI for TI calculators called Doors CS. To demonstrate the high reliability and throughput of his network he wrote NetPong, a multi-calculator version of the popular game that you can watch in a clip after the break.
This is definitely an instance where asking ‘why?’ is the wrong question. We’re more interested in the how, a question you can answer for yourself by reading the whitepapers he provided in both of the links above. [Christopher] knows what he’s doing, he proved that with his face-recognizing augmented reality.
Continue reading “Peer network using graphing calculators”