Sure. I'll do that later today. I have some work to do now.
OK, so here's my modified cable for the Vibrograf mic. The nice thing about these mics is that you can just unscrew the whole cable and swap it to another similar mic. Anyway, this is the end result:
This is what goes inside the mic. The springy part is just an electrical connector and the spring allows it to bend as you change the position of the clamp. The knurled part is the negative terminal, which is connected to the shielding braid of the cable. In my case, the cable is two pole, and the white lead is not connected to anything. The red lead is connected to the positive terminal, which is the springy bit.
This is the other end of the cable. The red lead (positive) is connected to the center pin and the shielding braid (negative) is connected to the other terminal, which is basically the whole larger metal portion of the plug.
And finally, if your mic already happens to have a 1/4" plug, you could just use one of these headphone adapters if your sound card/interface only has 3.5mm input jacks. You don't need to worry about the adapter being stereo. You're simply using just one of the two channels and the other one is shorted to ground.
Not a problem. It's a very simple mod and even if one doesn't have much experience with electronics, it's still very much doable on a very limited budget.
Now that I've been playing around with the software a bit, I thought I'd throw a few development suggestions out there:
-Average rate calculation over a period of time, say 1, 5 and 10 minutes for example. This is what the Witschi software does, and it is extremely handy. Ideally you should let the watch stabilize for something like 30 seconds to a minute and only then the software starts measuring. While the Witschi software does this automatically, TG could just have a button that you could click to start the selected measuring period. Once you have measured in 'all' six positions, you can easily read the results and draw your conclusions from them.
-Possibility to print out the results would be nice.
Hi my friends!
Unfortunately I had very little time to play with tg lately... I would just say thanks to all of you for your feedback.
@linux.author: I'm happy to learn that tg works on ARM!
@Aku Ankka, nauz: Long term averaging and printing are definitely on the to-do list!
Just to answer my own question and to bring up this thread - this setup works just fine. It doesn't need a preamp and that piezo mic seems to be less prone to ambient noise than a regular iPhone headset.
1. Piezo Clip On Microphone Pickup for Acoustic Guitar (~$4)
2. Mono 1/4" female to 1/8" male adapter (~$1)
3. 3.5mm Male TRRS to 2 Female TRS Audio Connector TRRS Y Splitter Cable Adapter (~$2)
4. Vintage MacBook Pro (already owned).
The vital part is that TRRS adapter as you can't just plug your mono mic (TS) into the headphones jack, it won't work.
Also there's a neat little software called LineIn (free) that allows you to hear what TG hears, just plug your headphones into the second TRRS adapter jack.