I'm currently working on a mood light project. At first I thought that mixing colors with 3 potentiometers would be nice (RGB). But trying to slim line the I realized that I could what I wanted with one potentiometer, using the color circle.
However it would be nice to be able to rotate the potentiometer more than a full rotation. Are there potentiometers that can do endless rotation?
Come to think of it, I'm also interested in something similar to the iPod wheel. What kind of device is that?
A potentiometer actually sounds better for this application, he wants an angle encoder so the knob always points to the correct location on the color wheel.
They claim 1,000,000 rotational cycles...so if you put it on a shaft rotating at 60RPM, it would break in two weeks. But it looks perfect for a manual rotary control or angle positioning system. Actually using it could be a small challenge, you'll need a flatted 4mm shaft and a small PCB for mounting.
Here's another home-made option. In your favorite graphics program, draw a circle and fill it with an asymmetric conical gradient (basically, the gradient starts at full white at one angle and fades to full black around the radius of the circle. Print this at the highest dithering resolution you can manage onto a piece of transparency; glue this to a circle of clear plastic. Now you can shine an LED through it to a phototransistor, and based on varying light levels get a pretty good idea what the angle is. Or, print the pattern on normal paper and use a reflective pair to measure the light that bounces off.
From what I have read so far. The type of potentiometer macegr suggests seems better. Mainly because I still will get values from 0-1023. With a rotary encoder I can only get 24 pulses per rotation/revolution. And with my limited knowledge on how the rotary encoder works I assume I only get 24 values. More values = more colours = nicer transitions .
Also working with a potentiometer is easier since I already have that knowledge.
With a rotary encoder I can only get 24 pulses per rotation/revolution. And with my limited knowledge on how the rotary encoder works I assume I only get 24 values. More values = more colours = nicer transitions .
Oh, you can get a lot more than that! They make them up in the millions. You get what you pay for. =)
They also go higher than the ADC resolution, using pulse train or square wave patterns, giving you more than 1024 unique values.
But an encoder is not what he's looking for; rather, he's asking for a resolver. Using an encoder would mean he'd have to home the wheel on every startup.
Oh yeah, guess got ahead and just read the "more resolution than encoder" - which a pot does not have.
But, here's the interesting part:
Come to think of it, I'm also interested in something similar to the iPod wheel. What kind of device is that?
It's just SPST momentary switches under a membrane =)
Edit: (at least the apple remote is, IIRC - I haven't gutted an ipod - but almost every time I've seen this, it ended up being switches under a membrane.)
Thank you all...
I think I've learned some new words in english without knowing their swedish counterparts. Hopefully I will use the information someday. I wouldn't have used the ULN2003 for this project if I didn't read about it in a stepper motor tutorial.
And for the rotary softpot I think that's exactly what I want. Or the contiuous rotation potentiometer. I did write the code for an ordinary potentiometer yesterday and it works quite well. I think I'll post some pics/video soon.
Hopefully I will use the information someday. I wouldn't have used the ULN2003 for this project if I didn't read about it in a stepper motor tutorial.