Need some helo from people good with small electronics

[d4mo]

I'm not all that experienced with small electronics. I did a little in high school but thats about it. But I was to start messing around and I found this at radio shack: LED Display. What all would I need for that too....function......

Do I need some kinda controller chip or what?

 

[dkozloski]

What you need is an education in basic electronics. A good place to start is at your local community college. If you can learn in a more unstructured environment you might find an online school. If you're serious and want to jump off the deep end like I did you can enlist in the military and let them school you.

 

[blahblah99]

You need the datasheet & pinout, for starts.

 

[flyboy84]

Assuming you are going to use this to display a count, or time, etc, you will need a BCD (Binary Coded Decimal) to 7-Segment Display converter. That takes numbers in binary format from whatever circuit you design and turns on the various segments of the display.

Edit: deleted example because it doesn't show up well.

 

[Lord Banshee]

74hc4543 is one example of BCD to 7seg chip.

But again you need to send a binary to the BCD to 7seg and this all depends on what you want to do.

I suggest looking online to "google", Digital Logic Tutorials.

 

[Leros]

Originally posted by: dkozloski
What you need is an education in basic electronics. A good place to start is at your local community college. If you can learn in a more unstructured environment you might find an online school. If you're serious and want to jump off the deep end like I did you can enlist in the military and let them school you.

If you are truly interested in a project, there is no need for professional education. Rather than learning 10,000,000 things, he can teach himself the 2,000 that pertain this project.

 

[bobsmith1492]

It really depends on what you want to do with it. At the very least, all you'd need is a power source and a resistor.

What are you trying to do with it?

Oh, and like Leros said, you can learn plenty by yourself without a "professional" education, so just ignore dkozloski.

 

[d4mo]

Well I know I need a powersource and resitor haha.

What I want to do, is hook it up to my computer(running linux) via Serial or USB, and have the display show my CPU usage percentage.

Maybe this project would be well outta my reach, but I think it would be fun.

 

[bobsmith1492]

Hm... interesting. The first thing would be to figure out a program that could capture your CPU usage as a number and send it out (I have no idea there). Serial would be MUCH easier than USB, I can tell you that from experience. (on the receiving end, at least)

You'd need an RS232 level converter (something like a MAX232 chip) and some logic to decode and latch the sent data. A small microcontroller (one of the TINY series would do fine - just DIP chips that you could put on a breadboard) would be the easiest/fewest component count. It would just need to take the serial messages, decode them, and output them to the display.

BTW, you'd likely need two LED displays (unless you never go over 9% CPU useage! )

Oh, and you'd still need a power source.

 

[d4mo]

Which one of these would be the Max232 needed? Mouser. What does the microcontroller do? Like I said I know a little but not alot.

If there is some website to look at that would be cool too.

 

[jmcoreymv]

Originally posted by: d4mo
Which one of these would be the Max232 needed? Mouser. What does the microcontroller do? Like I said I know a little but not alot.

If there is some website to look at that would be cool too.

The Max232N should be fine. The N and IN are thru-hole parts, and the IN just has an extended temperature range.

 

[d4mo]

Alright thanks.

So does anyone know of a good site to read about this kinda stuff on? I've been looking for tutorials and whatnot and I'm having a hard time finding anything.

 

[bobsmith1492]

Microcontrollers do whatever you program them to do, making them extremely flexible. In this case, you'd need to set up some sort of protocol between your computer program and microcontroller so they could communicate over the serial port.

For example, your computer program could simply send a number over the serial port every second or so. The microcontroller would have to be waiting for data from the serial port; when it receives it, it would have to output the correct numbers to the LED display.

This is easy to program using C on the microcontroller. Like I said, I don't know what you should use on the computer end to acquire the CPU usage information.

Look up info on C programming if you've never used it before.

Here's some sample stuff: http://www.captain.at/electronic-atmega16-serial-port.php

That's the sort of circuit you'd have to build and sample serial interface code for that particular microcontroller.

This site looks useful: http://home.wanadoo.nl/electro1/avr/index.htm...

Try avrsource.com - they have free development environments available for programming.

Wikipedia has a decent article:
http://en.wikipedia.org/wiki/Microcontroller