[Rene Schieritz]

Well there’s that and also the fact that this is an in-line flow meter. You’d have to use some sort of rather complicated and hugely variable calculation to convert the flow in the pipe (which would be directly related to the velocity of the stream) to the flow in the river. I think it would be better to look for existing structures, do some bathymetry and then install a level gauge. You can either use a pressure sensor or an ultrasonic sensor for that. Then use Manning’s equation on the cross-section of the river/stream/canal to get your flow from the river level.

[Rene Schieritz]

Hi @zrti0803,

I had some experience with this. I would suggest that putting the box in the water with an attached cable is a bit of a hazard. You could end up losing the whole thing unless you very carefully lay the cable into the stream bed. Access is also an issue – it’s much easier if you can just pull your sensors up from the side.

What we ended up doing was putting the boxes on bridges – however, we did work on private land so you may need permission to do this if you’re working with public. Our biggest problem was that the solar panel kept getting stolen!

For my sensors, I used a 50 mm PVC pipe and wadded pH, O2, conductivity and temperature sensors in there. You’ll need to carefully consider how you deal with the turbidity sensor. I think that sensor will drift A LOT because of deposition/fouling.

Sorry I don’t have any pictures…this is all a few years gone now.

Best of luck!

[Rene Schieritz]

Hi Brandon,

Have you checked the battery for battery health? While the Arduino is disconnected, connect one probe of your multimeter to the top of the battery, and one to the GND breakout on the datalogging shield.

Also, I would comment out the rtc.adjust function once you’ve set the time initially. I’m not sure if that makes a difference in this case, but it did cause problems for me using a different library.

[Rene Schieritz]

@Neil

I believe that the AquaPlumb system is Capacitive-based! You should be able to make your own, though at that size you may need a capacitance-to-digital converter like the TI FDC1004. I intend to get a free sample from them, and make a very similar system to the Aquaplumb using two pieces of copper tape. Again, these are things that I’ve concept-tested, but need field validation. So much to do, so little time!

Regards,

Rene

[Rene Schieritz]

Hi Kevin,

That sounds very good. I had similar plans to you!
So, you can definitely use that turbidity meter. The datasheet is a little bit weird (there’s a missing label, and I can’t find the Ground Pin!), but you know that you will have to measure voltage between pin 2 and Ground (I imagine this will be Pin 3 – may need some playing around!). I recommend you ask the manufacturer, or play around a bit.
Note, however, that this is a 5v sensor. If you operate on a 3.7V LiPo, you’ll have to boost the voltage for that particular sensor.
For simplicity, lets assume you’re using a 5V system, connect pin 1 to VCC, pin 3 to GND and Pin 2 to any analog pin on an Arduino-variant. Read the voltage off the Pin using analogRead(),which will output a number from 0 to 1023. Convert that to a voltage by dividing by 1023.
In a 3.3V system, it’ll be a little more complicated because you will have to boost your voltage, then use a ‘voltmeter circuit’ to measure the output voltage. There are tutorials online on how to do this simply-just google Arduino Voltmeter!
So, in this system, voltage will decrease (non-linearly) with increasing turbidity. You will probably have to create your own calibration curve.

For the distance sensor, what you intend to do should work. I was planning the same approach. Bear in mind, however, that that is not an outdoor sensor, and it may easily get damaged by environmental factors. You could look at something like thism though it is more expensive. However, if you’re really not concerned, or are confident that you can adequately protect your sensor, I guess you can always try :). Also, you may need a stilling well, as these sensors can be thrown off by wave action. You would need a fairly wide diameter pipe, as the sensor will otherwise read the pipe as its target!

Yes, stream flow and level are correlated for a particular point. However, the correlation is not particularly accurate (you have to know the rating curve of the point you’re measuring, and estimations won’t be precise). It really depends on what sort of accuracy you need here; if just stream level is good enough for your purposes, don’t go beyond that.
For accurate open-channel flow measurements, you would usually install a temporary weir or flume. This is quite a hassle, requires permission, etc.

I hope this helps! I look forward to seeing your results.

Regards,

Rene

[Rene Schieritz]

Hi Elle,

I’m trying out a capacitive sensor (similar to this instructable: http://www.instructables.com/id/Capacitive-Fluid-Level-Sensor/). I’ve got some pretty good readings so far, but I’m still doing more tests. Would something like this be of interest? Although I’m not sure if you’d want to go through making 200 of these!

Regards,

Rene

[Rene Schieritz]

Hi Neil,

I’m also approaching the level measuring issue, but with a tubular capacitive sensor. Pretty simple circuit, using a TS 555 in astable mode to convert capacitance to frequency, logged by a Seeeduino Stalker. Actually first field test is tonight.

Kevin, are you planning on measuring level/flow/stream velocity?

Regards,

Rene

[Rene Schieritz]

Hi Kevin,

I’ve been working towards a similar goal to you, and have mostly the same solutions. Developing a stream monitoring system in South Africa though. About the electronics: I’m not sure if you’ve considered this, but the normal Arduino boards draw quite a lot of quiescent current, due to the onboard regulator, USB etc. Are you looking at using an Arduino Mega Pro, from Sparkfun perhaps? Or, have a look at the Seeeduino Stalker; it comes with a built-in SD slot, RTC and Solar Charging circuit, which makes it pretty great for logging. If you use one of these, the neat thing is that you would be able to run your entire unit off 3.7V, so you wouldn’t need the three cells in series. It’s far more efficient, especially since the regulator on the UNO/Mega is not particularly energy efficient.
When it comes to the turbidity sensor: they should definitely work. I know some guys in Europe have used them. I just am not familiar with the type of output, so I wouldn’t be able to point you to a circuit offhand. Do you have a datasheet for it? I might be able to help you then!
Also, bear in mind that that particular turbidity sensor is an attenuation sensor, and is generally not advisable for stream monitoring. It can easily be affected by water colour, for instance. Of course, if the cheap option is what you need, it is very useful :).

With regards to maintenance, it depends on how well you design your system, but the probes will need regular calibration. I know Atlas Scientific claims that their probes (which are designed to run easily on Arduino, by the way!), only need calibrating once a year. My concern would be your nitrate sensor, which only has an expected life span of 6-9 months.

I’d love to hear more of what you’ve done so far. I’ll take some more time to properly draw up what I’m doing here soon!

Regards,

Rene

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