A while ago I posted a thread about a drip controlling valve being a very valuable first hack.
I did that because we are finding drips to be finicky to work with altho there still really great at being very finite.
That post was an expensive way to get drips to behave... this is a less expensive, and possibly better one.

The more I think about it this idea the better it gets, without getting more expensive!
Im alwase on the look out for an idea that is practically free, easy to modify, and takes up only a few grams when packaged in the peachy kit.

This one seems to be one of those so with that Ill get started.

A typical tone generating circuit charges and discharges a capacitor, it can be built just 2 transistors and a few other components at very low cost.
The smaller the capacitor the faster it charges and the higher the pitch is coming from the tone generator.

A capacitor is basically composed of 2 conductors with a very thin insulative layer in between them ... for example you can make one by sandwiching a piece of wax paper in between 2 pieces of aluminum foil. Slowly sliding one piece of foil off the wax paper would cause the capacitor to slowly drop in its capacitance.
If that varying capacitor was the one being charged and discharged in the tone detector, as you slid one of the foils sheets off of the wax paper the tone would very predictably rise in frequency.

now what if we did this....

Laminate one of the foil conductors so it has a varnish like coating.
Place that laminated foil strip along the side wall of your peachy printers top resivior, so that only the laminated portion is submerged in salt water.
Again you have 2 conductors both in very close proximity but electrically insulated from one another.
One conductor is the foil, the other is the salt water and these to conductors are insulated from each other via the very very thin layer of lamination on the foil.

As the salt water rises more and more of it covers the foil, increasing the capacitance very predictably.

variable capacitor--> tone generator = variable freq--> microphone input --> frequency mapped to height code = AWESOME PRINTS

I like this because its:
1 very hackable ( want a bigger printer, just get a bigger piece of tinfoil and coat it in varnish. )
2 its very low cost
3 it could be used in combination with the drip feed to help calibrate the size of a drip.
4 it still utilizes the mic input
5 it works despite the shape of your container. ( measures height not volume so tapered containers and fancy flower vases would just work )
6 it packs supper small and light.
7. it seems like the feed back would be far more explicit, liner, repeatable and predictable than drips, ( atho perhaps not a finite which is why its great that we can do both!)
8. You can try it now! and be a big help in the development of the peachy printer BEFORE you get your printer!

These are all great points but the first and last ones are my favourite.
I really mean it! It would be a big help if some of you amazing people in this forum would grab a simple transistor or 555 tone gen circuit, varnished or laminated tin foil and a container of salt water then Hack Post and chat about this idea until we know if its as good as it sounds!

a huge thank-you in advance to anyone that actually try's this and posts lots of pics and videos, for all of us to learn from.

PS here are some ideas that could make this idea better.

1 The foil could be rolled into a spiral shaped tube to get more surface aria in the water.

2 multiple layers of foil could be placed on the back and side walls of the printer to increase surface aria

3 insulated wire with just the tips striped could be placed at 4 or more heights in the upper resivior, each time one connects to the salt water it could make the tone jump up an octave (via conecting differnt resistances that charge the capacitor. each time a new resistor connects the tone would jump up in pitch. This could give us the explicite height data, making it posible to calibrate the printer automatically every print!

4 adding a walled off part of the bottom reservoir ( a wall with a small hole in the bottom )
you could make a resin free aria and add the variable capacitor to the bottom print aria as well, comparing the capacitance's might leave you with self relative instead of environment relative feed back, making it more reliable feed back.

5 placing a long wire 4mm away from the surface of the varnished aluminum would help reduce the amount of salt water electrons have to traverse to get close to the other electrode.
Doing this could reduce the effects of varying salinity and make for a better capacitor.


PPS

Any one want to take a crack at writing a python script that listens to the mic/ line in, returns a frequency and maps that frequency to height?
At the end of the day we need to know how well a computer can tell us the height of the water by listening to a real time microphone audio jack input.


Thanks again everyone, your ideas, hacking, and community nature are the best things that ever happen to peachy printer