code, circuits, & construction

Kimio Kosaka has made a way to program a virgin Atmega168 without a hardware programmer.  You use a modified version of the avrdude programming software that can access the extra pins of an FTDI USB-to-serial chip, do a little soldering on your Diecimila, and Bob’s your uncle, as the Italians say.

Calculating the configuration fuses for microcontrollers is always a pain. Many programming environments can do this for you, but in case yours doesn’t, here’s a handy fuse calculator for calculating the fuses on Atmel’s AVR microcontrollers.

Thanks to Zach Eveland for the link.

Most microcontrollers don’t have a random function. Random functions are not truly random, they’re actually a complex mathematical formula that results in a number that “seems” random. That can take up lots of processing time, so it’s usually the first function to go when writing a microprocessor language.

In fact, most of what you do in programming physical computing projects is to figure out how to deal with the world’s natural randomness and make it look smooth. A photoresistor read through an analog-to-digital converter, for example, will never give you a nice steady number, it always fluctuates with tiny changes in lighting that your eye can’t see. Your consciousness is a great leveller for the sensors that are your eyes, ears, skin, nose, and taste buds When you move a photoresistor from one room to another, your readings will be totally different, and all of a sudden, you have to re-calculate what is “average” and what constitutes the lighting change that you want. And that’s just one of many examples. The fact is, data from sensors is filled with the noise of the real world. Plan for it in advance.

Technorati Tags: pcomp, physical computing, programming

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