I am currently looking for a way to control a potometer via my computer. I have basic knowlege of electronics. This here: http://pdfserv.maxim-ic.com/en/ds/DS1669.pdf should work, i just need a way to interface it via the computer and since i have no knowlege of making programs or interfacing with the parallel or serial port i am asking for a little help. When im done with this project ill share it with everyone and i really think some of you will like it, as it can be applied to alot of different things. I just need to be able to change the value of the resistor and also maby have like 4 controlled outputs that i can use to hook up to transistors to turn the circuit on.
You can get pure electronic potentiameters, Xicor makes them. or you can get a motorized mechanical pot. They're kind of expensive, but having the knobs on your PC turn by themselves would be cool. The digi pots usually have a couple inputs, a pulse on one pin increases resistance, a pulse on the other decreases it, These usually have 128 steps. The motorized ones need something like a PWM circuit driving an H-Bridge. Not exactly trivial, but a Microchip PIC could do the PWM (Pulse Width Modulation) and PIC's can be gotten with either a Serial Port or USB. (this should give you plent to search on with google for more info)
id like to stay away from pulse width modulation as another project i have is dependant on it and its not fun. Ill look at those Xicor ones, it mostly just comes down to the software part of it that im stuck at. *edit* So far the best results i have found is from the one i origionally, i found a site that has all the info that should be needed to function with it. http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2748 now i just need some software to give out the pulses for it or use the digital input on it.
my onkyo hifi reciver did this if you turned of the vloume from the remote the knob on the hifi would turn too.. it was cool
Wow, tons of different types on that Maxim site. Sort of limited range of resistances available, but with the magic of opamps and transistors, you can get what you want. The step up/step down type are proably the easiest to control with a parallel port. There are lots of tutorials on how to control a P-Port. If you want more than 4, you may need to consider the I2C (AKA SMB) bus for addressable units. Good luck with your project, and getting parts from Maxim. They will give you samples (2-5) if you ask, although getting more parts may take some time, lead times of 6 weeks are not uncommon. They also have expedited small volume deals for under 24 parts, if you need more, just make multiple orders on different days.
