Let's Make Robots!

AD & DA converters - at a total loss.

I'm doing some non-robot project to learn more electronics. And boy have I got a lot to learn!
Right now I'm trying to take an analog signal, convert it into 8bit digital info through an AD converter, and then back to analog using a DA converter.

What makes it dificult is that I want to make it without any programming, with as few parts as possible.
I've found the PCF8591, which is a AD/DA-converter, but the way I understand the datasheet I will need to give it a I²C command to make it work. Does anybody know? Is there as way around this? Datasheet here.

It might be easier (and cheaper) to get to separate AD and DA converters, but how do I make them speak to eachother? I thought that I'd just jam the digital out from one into digital in on the other. Maybe feed'em a pulse from a 555 to set the sampling rate, and that would be it. But there are bundles of inputs on them both, And I can't understand if the need specific program lines, or just a high or low to start working.

I'm thinking that parallell would be easier, because then all the 8 bits would arrive at the digital ins of the DA at the same time. But if I choose serial, how is the DA gonna know which bit is the first if they just come streaming nonstop. Oh I'm sure there's a system for it, but I fear it might complicate things. So that's why I believe parallell might be better, but I'm totally ready to be proven wrong..

Oh yeah. The idea is to make a curcuit that takes hifi-audio in and lets out lofi 8bit audio on the other side. It's for some electronic musicians I know, they're into chiptune music...

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Good old Forrest Mims suggests a TL507 for AD and a DAC 801 for DA.  All the driving caps and resistors look pretty standard and the AD will need a 555 to clock it.  TI says the AD is 7 bit and National Semiconductor's is an 8 bit.  The circuits would all be discreet-no need to send anything but the signal you're converting.

Looks like the PCF8591 needs I²C to work.

Parallel sounds like the best option for your digital signals. It'll be hard to manage and debug serial comms with no micro/etc in the loop...

You should be able to handle the other control inputs with a 555 and a few transistors at most. Take a look at the DAC0800 and similar - they're about as simple as they get.