Forked from Pipe Meter (Updated) which is updated for Factorio 1.1.x from Pipe Meter.

Removed the tech dependency for logistic science. Now you can use the pipe meters in Pyanodons at a decent time.

Original Mod Description:

NOTE: This is mostly a proof-of-concept and to see if the idea had any value to the community. At this point, the idea has been shared and integrated/refined for later factorio versions.

Simple 1-tile entity that allows for connection of pipes to the circuit network. Should behave like any other pipe section, connecting on all four sides.
Level Meter:

This is for those that want to monitor fluid levels, but do not want to use a huge tank.

Range is read from 0-100 (99.9 actually). No more calculations, and think in percentages instead of total units.
Flow Meter Arrangement:

Because pipes offer a bit of resistance, adjacent pipe sections show varied levels depending on flow. Two meters can be inserted in-line to pipe flow, and their levels checked against one another to determine flow (see screenshot).

My rough test have seen about a 3% flow restriction when using this setup (That is to say that filling a tank straight from an off-shore pump takes only a few seconds more with the meters than with straight pipe). Max delta I as able to achieve was 10 (likely keyed to pipe 'diameter', and thus larger/smaller pipes will show larger/smaller max delta)
Notes:

This is actually a small, 100 capacity tank, and thus has a slight internal reserve. It responds well to level changes, but reacts slightly slower than the surrounding pipe sections to fluid level. It should flow the same as vanilla pipe. It can be used in place of a pipe section, or off to the side as shown in the thumbnail.