discussion / Sensors  / 10 December 2018

Water intermittency data logger

Hello,

I am trying to find a simple cheap data logger that can record simply the presence or absence of water for stream intermittency surveys. The best resource I've found is a way to reverse hack a HOBO Pendant - however the resource does not have information detailed enough for me to do this myself. https://www.onsetcomp.com/files/Chapin-STIC-WRR-2014-reprint.pdf

Does anyone know of a CircuitHub style DIY design or an pre-made affordable product? If not, I'll reach out to the authors of the above report. If anyone is interested in what I hear from them I will share it. 

All the best,

Erick




Hi @elundgren 

How simple do you need to go? If it's presence or absence then you could grab an Optomax digital liquid sensor and an Arduino Nano. Encase it in epoxy with a decent sized Li-ion battery and a simple Arduino script will log every event.

More here - https://www.adafruit.com/product/3397

Cheers,

Alasdair

Hi Erick, 

Over on Twitter, @Michael.T also had a suggestion and included a tutorial link.

Could you use a force sensor resistor and have that linked to a small float in the water so when water runs by, it pushes a lever against the FSR and gives you a + reading? @arduino https://t.co/fibPoNJaqL

— Michael Tlusty (@TlustyM) December 10, 2018

Steph

Hi,

Just thinking out loud, but a pretty cheap solution might be a TemTop waterproof temperature logger, ($20) but you remove the thermistor and replace with a tilt switch.  Supply the logger with a float so it flips up in water and lays flat if dry (or it rolls, or otherwise changes attitude).

-harold

Hello everyone,

Spent a couple hours on this the other day and I have a cute little LED and a serial printout responding to an Optomax digital liquid sensor. The sensor works great: it does not react to damp sediment, only to open water, which is perfect. My next steps are to figure out battery power and data storage (either a serial flash chip or microSD - depending on whether I want to swap sensors in the field or just swap SDs). However, I have read online about arduinos not possessing the ability to turn off for intervals - meaning that the batteries will draw down way more quickly than one would hope. And they lack an internal clock, meaning that I'd have to add a clock or relate data to a start-time I record as they are deployed (which would be fine).

@alex_rogers suggested using the arduino prototype to firmware build a Happy Gecko Processor - which would include a clock and power management. I'm going to begin looking into that process.

Finally, if anyone else in the community is interested in this kind of sensor for their research, please let me know! My use will be in deserts in the SW USA, to track changes in water availability in remote wetland springs and to relate that to trail camera and acoustic data (praying for the next AudioMoth GroupGets!). 

Many thanks and happy solstice,

Erick