Getting into Digital circuits
 

I would like to get back into electronics to build some projects. Back
many moons ago in HS I did some stuff with electronics simple stuff with
555 timers and things. I'm hoping I can find someone that is familiar
with building digital circuits that could use some help programming,
there's nothing I do better than programming. Let me describe the
project I have in mind now so I can get some input on what I need to buy
to get started.

I would like to be able to use a microprocessor of some kind that I can
program via RS232, that will turn on or off a large number of lights. I
was thinking I could have the processor output the number of the light
it wanted, and if it wanted to turn on or off. Maybe it would just
toggle the light, so every time a lights number came up, it would just
alternate it between on and off. My first project will have about 30
lights, but I would like the design to be expandable. Since an 8 bit
number gives us 256, I was thinking that would be the limit. Maybe have
modules that will control a group of, say 8 lights, that can plug into
the output of the processor, then another module can plug into the
previous one. . . For now the lights are just going to be 20mW LEDs,
but I have plans for projects that will need either around 5W lights, or
gangs of 10 to 20 LEDs. So I will need some kind of relay, I guess a
solid state relay of some kind would be best. As I glance through my
mouser catalog I see several different programmable controllers that
look like they would work for something like this, but I have no idea
which one to use. Thanks in advance for any suggestions.

If this isn't the best NG for this please let me know which one is.
There seem to be a lot of electronics NGs.

Also I recently purchased a few prototype boards on ebay and one came
with several IC chips and things. Where is a good reference that will
tell me what they all are and what they do? Back in HS we had a
reference book that told all about various common IC chips and gave some
sample circuits. Surely these days there is some on line reference like
that.

--
Chris W

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"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

These sort of applications are ideal for PIC chips, simple to use, require
almost no auxilliary circuitry, and are easy to program. Very steep learning
curve, and the programmer will set you back somewhere in the order of $200
AUD, but the PIC 18F672 has provision for RS232 and multiple outputs (22).

Paul

loedown wrote:

These sort of applications are ideal for PIC chips, simple to use, require
almost no auxilliary circuitry, and are easy to program. Very steep learning
curve, and the programmer will set you back somewhere in the order of $200
AUD, but the PIC 18F672 has provision for RS232 and multiple outputs (22).

Paul


What about something like the RABBIT Microprocessor modules? Wouldn't
that be the easy way? Could I program something like that in C?

Also does someone make some kind of IC chip that takes say 3 bit binary
number for input on 3 pins and then makes one of 8 output pins go high
based on the input binary number?


--
Chris Woodhouse
3147 SW 127th St.
Oklahoma City, OK 73170
405-691-5206

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
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"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

Had a look at those Rabbit micros, they are like an upscale version of the
PICs. There is no reason why they wouldn't work as well.

As for your other question, from memory the 74138 does that.

Programming a device to take binary input and switching one of eight outputs
would be quite easy though, that's reason for these programmable ICs, no or
limited additional support circuitry is required

Paul

loedown wrote:

Had a look at those Rabbit micros, they are like an upscale version of the
PICs. There is no reason why they wouldn't work as well.

As for your other question, from memory the 74138 does that.

Programming a device to take binary input and switching one of eight outputs
would be quite easy though, that's reason for these programmable ICs, no or
limited additional support circuitry is required

Paul



Well what I want to do is switch on of a few hundred outputs. The idea
is to have an 8 bit binary number determine which one is switched, have
modules with 8 or so switches each on them and have them stackable so I
can expand to up to 256 switches controlled by one PIC


--
Chris W

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
http://thewishzone.com

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

Keep in mind that the PIC chips can source 25 mA on any of the output pins,
so decoder ICs, then transistors / relays would be the way to go, but
reasonably expensive, for wht you are trying to achieve

Paul