While the current mechanical setup is in the guitar, and the amplifier pcb is fastened to the guitar also, I decided to have a look of another kind of mechanical/optical setup, which I tried very shortly in the beginning.
It was left aside, as I didn't have an amplifier circuit to provide enough boost back then. But now that I have, I thought that re-visiting that design could be interesting.
Don't mind the bigger setup, as the one, that I'm babbling about, is the small one on the upper side of the picture. It's glued in place:
The sender(ir-led), and phototransistor have 50 degrees angle between them. No any particular reason for that angle, other than to see, does the concept work:
That test housing has a "backrest" to keep the sender/receiver combo from rotating around, when adjusting the height. Seems to work quite well.
As can be seen on the first picture, that thing was tested on the thinnest string(~0,2mm). If that works, any string thicker than that should give even more usable output.
To my surprise, there was stronger output, than was expected, after adjusting the pickup closer to the string.
So far, I have only used the scope to see the results, but it's the resulting sound that counts after all. I haven't got that far yet, as projects like this tend to expand(explode) in form of countless possibilities involved.
But yes, I think the mentioned sort of setup could very well be more appealing to the most of experimenters, that are willing to get their feet wet.
Quick summary of the two lately tested concepts so far, but take it with pint of salt:
One with sender/receiver pair in opposite(horisontally) sides of the string:
+ immune to string bending(which is also a horisontal movement)
+ the "sweet spot"(max. output) could perhaps be found by measuring the current consumption of the amplifier circuit
+ overall output level
- not a very practical to use, as the sender/receiver pairs (and their housings) protrude above the strings, so it's not possible to dampen the strings in natural palm-assisted way.
Then the one, that relies on reflecting the ir-beam from the string surface from the below:
+ remains under the strings
+ allows free playing, and string dampening at will
- rather sensitive to string bending(maybe not so, if multiple pairs of sender/receivers were used)
- can't think of reliable way to judge the "sweet spot" yet
But as always, all that needs a lot of testing.
To expand the subject even more, I'm thinking of ordering some hall-sensors, to see, if they could be
abused used for this purpose. But that's beyond of this thread, though.