Toilet Pulse Meter?

I'm looking to read pulses from a tiny on/off "flow" meter I read about, but can't seem to find out where to purchase one. Anybody know where to buy one of these?

I wonder if a plumber would know about them, or perhaps electricians...

The intent of the project is probably important as to what/how things are to be measured. Unless leaking, toilets are usually discrete event driven gizmos, and if in the US with a fairly new toilet, ~one gal. per flush event can be assumed.

I've done exactly this using a ZD1202 flow gauge that's available in Australia from Jaycar, and from other retailers elsewhere around the world. There is a link to the datasheet on this page: