Digital Electronics project - servos and more

[mluckham]

Originally Posted by efoote868

I would like to use PID control for the servos I create; but I would definitely need a micro controller for that.

http://www.ecircuitcenter.com/Circui...pid/op_pid.htm

[efoote868]

Originally Posted by mluckham

http://www.ecircuitcenter.com/Circui...pid/op_pid.htm

Alright, so there is a way to do it without a micro controller, but I don't want to try to tune an analog PID...

I think what I need to know is how much of this circuit I would build myself, and how much I would buy just in chips (make my own H-bridge vrs. buying one, make my own analog to digital converter or getting it on board with the PIC, etc.)
Any thoughts?

[efoote868]

(Sorry for the double post, but I'm going to answer a few of my own questions)
I do not have to build any part of the circuit myself if it is available, for instance, the H-bridges, I can just buy as is, or the analog to digital converter can be embedded in the PIC, as well as the PWM outputs.

I've got a question as far as the PIC goes, which of the line have analog inputs, and pwm outputs? Which chips are able to be programmed in C?

[mluckham]

Originally Posted by efoote868

I've got a question as far as the PIC goes, which of the line have analog inputs, and pwm outputs? Which chips are able to be programmed in C?

Get onto Microchip's website and dig into the manuals.

[Jay Lundy]

If you decide to use a PIC, you can either go with the PIC16 or PIC18 series.

PIC18:

This is the same product family as the one in the RC, so you can use the same development environment (MPLAB + mcc18, but not IFI loader). Most of these come in non-DIP packages or are too large for what you need, but given your requirements the PIC18F1220 will work.

PIC16:

These are generally smaller and less powerful than the PIC18, but still plenty powerful for your needs. The problem with PIC16 is there are no free fully featured C compilers for it (as far as I know), but there are some free limited ones you may be able to use. The assembler is free if you're insane. There are too many PIC16s that match your requirements, so use Microchip's product comparator to find the right one for you (get one with flash memory, ie 16F series, and at least one CCP for PWM). The PIC16F88 is a popular choice.

With any PIC you'll need to find a programmer (to actually get the code onto the processor). You can buy one from microchip, but they can be pretty expensive. Or you can try to google some cheap versions you can build/buy (make sure to get the software you need too).

A good alternative to a PIC is an AVR. Unlike PICs, there is an AVR gcc C/C++ compiler that comes with a great set of tools. You can compare AVRs here, but I recommend the ATtiny44. You'll also need a programmer for the AVRs. There are some cheap ones, but you'll have to find one that works with a ATtiny.

[keen101]

http://ladyada.net/make/mshield/index.html