Hi Samantha,

This looks like a really interesting and beneficial project. Wishing you all the best with it.

Are you scouting for sensors that are archival and deployed / recovered over set period of time, or do you need telemetry / daily / hourly data to monitor change from tethered buoys etc? We are working on a similar solution with another partner, although not with microfuid-based sensors, but there are similar barriers regarding cost reduction and data collection.

Kind regards,

Alasdair

It sounds like you're looking for multiparameter probes to deploy in the water to log in situ readings as part of the baseline you want to establish, and you might be deploying BRUVs, doing video transects, or taking soundscapes in addition, if I'm not too far off the mark.

The multiparameter probes will run you around USD10k each, kitted for let's say pH, conductivity, DO, turbidity, nitrate, and temperature.  If you can rent these probes and the manpower to run them, that may be the best option if local expertise is lacking, as there are subtle gotchas.   You might want to look into an automatic winched system which raises and lowers the probe, so you get readings throughout the whole water column.  This may not be much more expensive than having 3 probes (at surface, bottom, and mid-depth).  Other advantages include reduced biofouling (since the probe parks in air) and potentially reduced maintenance load due to this.  But the disadvantages include fishers tying up to the system and boats colliding with it, and birds pooping on it, all of which have happened to me.

What exact nutrients or parameters are you trying to measure? 

Hi,

Can you clarify what you mean by "does not work"?

If I were to guess, I'd say the firmware temperature compensation tables for the load cell tops out at 40 deg C (104 deg F).  Everything else should still function to 70 deg C, which is the most common and most lax rating for electronic components.

If this is the case, then the scale probably still retains precision (output is repeatable) even if it is inaccurate (output is wrong-ish), so it's possible to calibrate it.  This could be as simple as tabulating the measured weights of standard weight samples at different temperatures, to adjust the output of your scale in post processing.  Unfortunately this means you also need to log the temperature, and you'd want to store the scale at close to ambient temperature so it quickly equilibrates (a good idea regardless) when you need to use it.

Hi Guy,

Sparkfun carry an ECG module, but I don't know if this will work with sheep/goats.  They've got lots of temperature sensors too, but I would look into something like MAX30205 if you need accuracy.

Do you mean the sensor itself (that you're going make a tag out of) or a datalogger that records heart rate (sensor incoporated into a tag already)? Vectronic make some good terrestrial animal physiological sensors.