As we implemented an old Wine Barrel as a raintainer, I would like to see how full it is.
So I designed a floater with a wire and pulleys, to show the level on the outside of the barrel.

Please 'LIKE' before collecting!
Thomas
www.3daybreaker.blogspot.com

Some hardware is necessary, like M6 bolts, a m6 bolt-connectornut, some washers and a piece of rope, as well as silicone to make the float watertight.
The float is a 2-piece part. Put a wire through the hull, put hex M10 nuts on the bottom pile, glue the wire to the pile and glue everything together and seal it. (I used hot-shrink-wrap to fix the wire to the pile!) Beware: I your print of the float is not manifold, the float might sink, resulting in a not-working indicator. If so, seal te float with a sealant.
The "STIFT"file is the sinker that you can put hex nuts on
In the Floater, 4M10 Hex nuts do the job

The pulleys need sanding of the spoke ends before assembly. If done, you can hammer them together in a tight fit. Maybe some cyanoxx glue in between the halves.

The lower pulley can be mounted on the Psteun part, but you can also print an additional Niveausteun part and mount it to the floor.

Update 2016-07-21: files with v4 have pulleys with deeper rims and higher mounts.
Update 2015-03-13: Niveau-Wiel3 is a redesign of the pulley, which holds any rope better in position.
Update 2014-07-20: If your printer does not do overhang so well, I have split the pulley in two halves (file Wiel2) .
Update 2014-07-20: a set of 2 supports laying flat is added.
Screw the stands on top and at the (outer) edge of the barrel. (Mine has a steel trim so a drill is needed)
Guide a piece of wire through the float , by the 2 pulleys and with the indicator at the other side. Add some weight to the float, so it will still float, but outweigh the indicator :-) Glue the float bottom to the float and seal it airtight with silicone or likewise. If water comes in, the system does not work any more. Beware: If you tie the indicator to the wrong wire, The indicator wil raise-up when water level goes down, (so make a reverse scale to compensate :-)

Never print the mockup .STL, it is for decoration only :-)