P3D Re: Some hacker projects (long)

[Tom Hubin <thubin@xxxxxxxxx>]

Hello Tom,

> I plan to use a microprocessor to control the timing, and an LED
> readout to set the timers.  I've found the processors and solenoid,
> need to buy parts. I think I can teach myself the assembly language
> programming.

You don't name the processor but I will compare two that I am familiar
with. The PIC is very popular but I prefer the Atmel AT90S8515
microprocessor. For $50 you can get the developent kit. It includes a
microprocessor, assembly language, programming and test board,
programming cable. It plugs into the parallel port on a PC for
programming. You provide power to the board but that is just 9vdc from a
$10 wall transformer. 

There is a bunch of internal programmable ROM for your program, RAM for
variables, EEPROM for power off storage of data. The micro alone is $5
to $8 depending on speed and package. No other voltages required to
program it. 40 pin DIP unless you prefer surface mount. Wire wrapping
works great for one of a kind.  

It also has built in RS232 interface if you have a need to get serial
data into out of your gadget. Something the PIC does not have. And 32
I/O pins to control or monitor whatever. You give up 2 I/O for RS232 and
4 I/O for programming if you need those features. Plenty left for LCD
control. I use 22 I/O for my 3.5 digit LCD. You can do the design so
that it is programmable while it is in the circuit. You do not need to
move the micro to a seperate programmer. I LOVE that feature.
 
> (I didn't include projects completed before August, nor the ones that
> failed miserably.  You get those from time to time.  Most notable was
> the LED based slide illuminator.  After designing my own "rock
> tumbler", I tumbled LEDS to "frost" them.  Everything worked
> perfectly, except now none of the LEDS light.  Might have been the
> static. $60 worth.)

Try sanding the LEDs with very fine sandpaper. Better yet, buy them
already frosted. Give me a better idea as to what you are trying to
illuminate. I am an optical and electrical engineer and may be able to
make helpful suggestions.

Tom Hubin
thubin@xxxxxxxxx