DFRobot Gravity KIT0139 Depth Sensor – Routine Interference?

Hi James, very interesting. I wonder which Analog port on the mayfly you are using,  ADS1115.?

One test I do, to verify the sensors response, is put the sensor in a simulated stationery stream, (jug

Hi James, very interesting. I wonder which Analog port on the mayfly you are using,  ADS1115.?

One test I do, to verify the sensors response, is put the sensor in a simulated stationery stream, (jug of water) with a solar aspect, stable power supply voltage, and measure water temperature and water temperature together and see what it reports.

Water temperature sensors https://www.seeedstudio.com/One-Wire-Temperature-Sensor-p-1235.html

These sensors typically use a varying resistance with pressure change (water depth) and are influenced by temperature. I’ve seen some sensors that have nonlinear changes with temperature – depends on internal algorithms. The KIT0130 states it has temperature compensation, but not what the range is – but who can complain at the price.

Eyeballing your graph – its +-/10mm – but whats the temperature change. 🙂

One set of measurements I did on two individual sensors that where in the same family, with a stated temperature specification showed the non-linearity in some of the sensors. They where returned.

 

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Could it possibly be a problem with the temperature inside your logger box rather than the water temperature?  Maybe Shannon can pipe in and confirm, but I remember that we used to have issues like t

Could it possibly be a problem with the temperature inside your logger box rather than the water temperature?  Maybe Shannon can pipe in and confirm, but I remember that we used to have issues like this when we were using black boxes with clear lids facing summer sun.  I think the Mayfly’s ADC starts acting up when it gets too hot.  Are you recording the Mayfly’s DS3231 temperature?  It might show something.

I haven’t found a way to re-temperature-correct a depth sensor that’s built-in temperature correction has gone awry.

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Those temperature shouldn’t be a problem.  If I remember right, one of our first box iterations ended up acting like a little greenhouse and turning into an oven in the summer.

Could it be the

Those temperature shouldn’t be a problem.  If I remember right, one of our first box iterations ended up acting like a little greenhouse and turning into an oven in the summer.

Could it be the amp-to-volt board that’s the problem instead of the sensor?  Do you have a second one you could test against?

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It would be interesting to see if the anomalies in sync with periods when the Mayfly’s battery voltage is peaking, i.e., during maximum solar input.

It sounds like you have the sensor on a sepa

It would be interesting to see if the anomalies in sync with periods when the Mayfly’s battery voltage is peaking, i.e., during maximum solar input.

It sounds like you have the sensor on a separate circuit from the Mayfly. If that’s the case, should the grounds tied together between these two circuits? I’m not an electrical engineer, so I don’t know – just throwing it out there.

Matt

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