Open Flowmeter 2.0
Geography River Studies, measuring velocity
Flowmeters are problematic, you can use a ball or an orange and time it moving between 2 known points, but you will get different results every time. You can buy an electronic flowmeter but these are expensive, they break easily and the screen with battery case is not waterproof nor even in most cases weather resistant.
We have used these options with our study groups and always succeeded in collecting our data, however, the expensive flowmeters always had problems and the orange was lacking repeatability. In 2018 Eben started work designing an open source flowmeter, it took lots of iterations and mistakes to finally make a working unit. The unit was released on our: https://gitlab.com/zenquest/fieldwork-flowmeter/-/tree/master/ and build instructions were added here: https://hackaday.io/project/176376-open-flow-meter where our project won the:
We also did extensive testing using velocimetry software to measure river flow rate with digital video. But this (for now at least) is too time consuming, complicated and error prone for our student groups to reliably collect data. So for the last 5 years or so we just kept using our v1 open flowmeter for our river study programmes. However, this unit had many issues, it did its job, it was cheap, easy to make, easy to fix but it often broke down, we needed many spares to finish every set of fieldwork, the cable had many problems and the display stopped working when it rained or was dropped in the river. The on off switch was delicate and could easily get switched on by accident when in a travel bag.
Our new v2 version fixes all these main issues and adds lots of extra features:
