Success! Sort of…
Apr 23, 2010 Arduino, Gear
Posted by
irfon
It worked! The new soldering iron was beautiful, so you can stop being stressed about the responsibility, Andrew. :) It really made it a joy to solder.
The overall hack is a tad unstable, so I haven’t made a video of it yet or labelled it or anything. I’ll try to take some photos, though. I have some ideas as to what might be happening.
Here’s what it does at the moment that’s desired:
- Switch selects between internal and external sync modes.
- Switch selects between run/stop modes when internally synced.
- Knob selects tempo when internally synced.
- When externally synced, tempo is correctly retrieved from incoming MIDI clock.
Here’s what it does that’s less desirable:
- Sometimes it takes a long time to switch between modes — longer than I have a good explanation for. Other times it switches more quickly.
- Sometimes when you touch the knob or the switches, the whole thing kind of freaks out a bit.
- Sometimes it produces very strange output for a second or two before successfully switching between modes.
It was doing this during the testing phase when I was just using a bunch of alligator clips to hold everything together, so I had thought it was just the noise and unreliability of that. Now I’m not as sure. It almost seems like something’s shorting with the metal plate that it’s all mounted against, although I thought I’d triple-checked that that wasn’t the case. The one thing I’m wondering is if the knob, which is on the back mounted almost flat against the plate, is causing some kind of issue. I could put a washer or a nut on it behind the metal plate as a kind of spacer.
One thing that I should mention is that I kind of built this as a bit of a hybrid between permanent and temporary installation. I don’t have a screwshield or anything of that sort for the Arduino, so all connections to it are being made through these sort of push-in solid cables like you’d use when prototyping on a breadboard. My circuit, simple though it is, is actually on a mini breadboard that’s mounted to the plate. So all of those connections between the Arduino and the breadboard are not soldered in. All the connections to the knobs and switches are, though, and anything else which I realistically could. So if I can’t find some other source of the problem, that might be a next step — actually putting this on a board and soldering it all down. But those connections seem pretty solid, so I don’t think that’s it. I’m leaning toward the knob. I suppose I could use the multimeter to test if the value it sends ever goes totally wonky.
Anyway, I’ll post some pictures and videos at some point, either later to solicit input on the problems or when I get it fixed up.
April 25th, 2010 at 11:36 pm
I’m glad that the iron is working out well! Getting a good iron really makes DIY electronics work so much better. The soldering part actually becomes an enjoyable part of assembly, rather than an annoying / tedious process.
The glitches you have do sound like a bad ground connection, or other connection issues. One potential way of finding out if they are related to the front panel would be to take a piece of semi-rigid cardboard (like a cereal box) and mount your controls on that instead. If it works properly, then that would be a good indication that having everything mounted on the metal panel is a problem. Most switches and potentiometers should have the terminals isolated from the body of the switch.
Are you using the measured resistance/voltage at the output of a potentiometer to switch between modes? It could be that the wiper is a bit scratchy, which is causing it to quickly flick between values when you adjust it. If your program doesn’t check to see that the value is constant for a short period of time (50 ms, maybe?), then it could also cause those sorts of glitches.
Good luck with your debugging!
[Reply]