3 ms·
The digital pot the other person posted uses 7 bits for 0-10k ohms, so it’s much less precise than a real trim pot. For most arduino type applications that’s pr
by smogcutter 6y ago
The digital pot the other person posted uses 7 bits for 0-10k ohms, so it’s much less precise than a real trim pot. For most arduino type applications that’s probably fine, but if the goal is to get super anal about nailing 33 1/3 rpm exactly, and keeping it in tune over slight environmental changes, then it really isn’t good enough.
I guess it would be fun to come up with some kind of feedback scheme that trims the digital pot automatically. But as a practical thing rather than a for the heck of it project it really doesn’t seem to be worth the effort over just using a pot.
- tuatoru 6y ago> some kind of feedback scheme that trims the digital pot automatically Yeah, PID controllers are around, I think. (proportional-integral-differential.) Quite easy to do on an Arduino if not readily avaialble. But better to PWM-control the drive transistor directly than adjust a digital pot.
- smogcutter 6y agoGood call, pwm would be the way to go. I feel like most hobby projects of mine end like this: bring home a bag of stuff from fry’s, realize while futzing with the breadboard that it’s a much simpler problem than I first thought, wind up with a bag of unused stuff from fry’s because I don’t want to drive back to Burbank to return it.