On Apr 22, 2008, at 12:25 PM, skipp025 wrote: > > The 555 is one of the most useful electronic circuit chips ever > made. It has a fairly large number of possible simply configured > mono & astable (cycle) circuit operations. And it's just as easy > to get lost when trying to use it for specific tasks.
Additionally along the "do-it-yourself" lines... Taking a small amount of additional time to learn how to program a microcontroller like a Microchip PIC or an Atmel AVR, and you no longer have any of the limitations of a 555. (Of which there aren't many, but... still.) Virtually every piece of consumer electronics moved to these highly useful little chips 10 years ago. They're also everywhere in your car (in specialized "hardened" varieties... automotive electrical systems are hard on "computer" hardware), etc. Learning them will lead to other more advanced projects later on. And implementing a timer in one, is barely a "medium-beginner" stage. Most manufacturers provide sample code to "blink an LED" and if you can figure that timing loop out, modify it and play with it a little bit, you're about 30 minutes to an hour away (as a new beginner) from a working timer circuit that will do whatever timing you want... you type in the instructions, and the chip does it. You apply some very basic electronics to that to perhaps drive a transistor as a "switch" so you can sink or source more current than the microcontroller can handle a LOT of current anyway) and learn the joy of bypass capacitors to keep RF in/out of your circuit (since you're using the thing around radios!), and you're done. Don't like the timing? Plug your $39 programmer back into the circuit and put a different timing value in the software running in the chip. I wouldn't say it's always more flexible than something like the 555, because a guru can make a 555 do things it never should have. But it's a lot easier to get your head around if you have any kind of computer background, especially a little computer programming experience! Not to mention, fun! -- Nate Duehr, WY0X [EMAIL PROTECTED]
