Stamp LED Control & Electronics Books

MysticalMatt517

This is probably a pretty simple question, but I'm a raw newbie to the world of electronics and stamps.

I just read through the PDF of the "What's a Microcontroller" book to get an idea of how the stamps work. I see that you can control an LED using a resistor and having the stamp control the power flow.

It seems to me that the number of LED's you can control is limited by the outputs available on the stamp. I'd like to control 50 - 100 LED's... Not individually of course. I'd be fine to wire them in series so that they all turn on / off.

(Ideally it would be like a string of Christmas lights hooked to one stamp output)

The first problem that comes to mind is power. I'm thinking there's probably not of enough amperage to make this work. Is it possible to hook the LED's to a seperate power source and still have the stamp control a switch?

Finally, can anyone reccomend a *really good* beginner book on building electronic circuits? I'd love to learn, but most of the stuff I've found online is either really shallow or over my head...

Joms

That is very possible. A very low tech way to do it would be to use a relay. I would really recomend looking at DC solid state relay. This would be all electronic and allow the stamp to control leds or any other load powered by another power source.

SRLM

For something like an LED (or string of them), I'd stay away from a relay. You're going to need a transistor and a diode to power the relay, so why not just use a darlington array? With the array, you can control quite a few LEDs on a single string, and not have to worry too much about current draw. For controlling more than 16 groups individually, you can multiplex or use an interfacing chip to expand for you.

For beginer books, nothing beats the Parallax Stamps in Class series (available for download free). Take a look here for more suggestions:

http://forums.parallax.com/showthread.php?p=741483

MysticalMatt517

Both of you rock! Thanks for replying!

The stamps in class books are available as PDF's? Awesome. It looks like there's a lot of good info in the thread you linked to. At least I have a starting point for my project now.

vaclav_sal

If you want to go past the basic "turn on LED" routine try MAXIM 7219 chip. It lets you·control 64 LED's individually and you can also learn·how to use serial data transfer protocol. Just for learning and fun·I would stay away from relays for now.

SRLM

vaclav_sal said...
If you want to go past the basic "turn on LED" routine try MAXIM 7219 chip. It lets you control 64 LED's individually and you can also learn how to use serial data transfer protocol.

Interesting chip! I did some searches, but the cheapest that I found was $10.80 from digikey. Do you know of any sources that sell the chip for less? I'd like to give it a try.