[neilh20]

Wow thanks for the details. Great to see the Sodaq Mbili/GprsBee and hear its good piece of equipment.
When it comes to attaching in the stream be, depends on stream conditions, soil type and vegetation. In the US concrete in the stream channel probably would require a permit – but I’ve seen hydrologist working for the NOAA that will pound a stake into the stream bed, tie it into roots if available. These have been for pressure sensor based equipment. The attached picture is in a channel with the stake pounded into the bed and then a secondary stake tying it into the top of the bank. This was installed in 2007 and flooded to bank height in 2008.

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   LDSR-LCC46-01b-small.jpg
   

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   080104-0940-LCC46standpipe800x600.jpg
   

[neilh20]

Hi Rene
Thanks for the reference on the FDC1004 – there is an App Report
http://www.ti.com/tool/tida-00317
Capacitive-Based Liquid Level Sensing Sensor Reference Design

I’ve attempted some custom PCB electrode for measuring water depth. The discussion is excellent. The challenge is field calibration – if looking for a 0-1m (for example) change – how to know when installing in the field and measuring capacitance, that the specific numbers being measured represent 1m of length.
The reference electrode design is a bit un-wieldy – but useful for discussion and experimentation.
The holy grail is a simple wire.
I found some unusual properties of the capacitive field.
I had the Aquaplumb in a column (3″/8cm dia pipe) of water, and varied the height.
I got useful readings. However, even with a full pipe – the wire in a reasonably large volume of water, when I brought my hand (a relatively small volume of water) to about 10-30cm away, it did cause an effect on the reading. The only explanation I had was there was a really extended field effect, but something really interesting.

From the reference design idea – perhaps some aluminium (or copper) tape could be used.

[neilh20]

Hi Rene
Yes the Aquaplumb is capacitve sensor based, tried it and tested it.
Then I took the basics and applied them to the Teensy-LC which has capacitive inputs and tried the same on that.
So I was interested in what your results are – the capacitive water depth measurement does produce numbers … so it worked but I came across some issues with calibration …..
I tried solving the calibration issues by generating three capacitive depth sensors in parallel, but finishing at different heights – with the idea of detecting when the water level exceeded one capacitive sensor it would indicate one known height was exceeded and could be used to calibrated the other heights.
So I was interested to see what you came up with.

The issue is I’m looking for a tight specification of changes in water depth over 24hours – monitoring the hydrograph over a diuranal cycle.
Easy/low cost simple Measurement traceability – managing/verifying no sensor drift – is also a requirement

[neilh20]

Rene, I got the bare bones Aqua Plumb when they kickstarted it:
http://www.vegetronix.com/Products/AquaPlumb/
They filed off all the numbers on the chips, so not clear how they are doing it.
Be interested to hear how you got on and compare notes.

[neilh20]

Hey interesting thread here.
Seems like a lot of people have some great ideas on this. My 2cents is its a really difficult area – specifically for what Rene has pointed out – the quiescent current.
Unfortunately Arduino does not cultivate a low power paradigm – Arduino core has said dealing with low power event based software is too difficult, but PRJC.com is a step beyond the core.

I’ve got a solution for stream monitoring that I’m working up –
http://www.meetup.com/Nerds-For-Nature/photos/26131259/#437612397 which I talked about at this years San Mateo Maker’s faire – see the poster to the left of guy/me – “Wireless Stream Sensor Road Map”

For anybody who is interested in a working on a Specific Conductance probe I created this as a starter.
https://makerspace.com/projects/specific-conductance-probe
The electrodes could be titanium – the challenge is how to plan to clean the electrodes of the ever prevalent slime build up.

Some instruments have a wiper, but I haven’t figure out how to easly do this.
Slime is often watershed dependent but a physical cleaning seems to be the most obvious solution.
http://priede.bf.lu.lv/grozs/HidroBiologjijas/FieldGuideAquaticPhenomena.pdf
http://www.gov.pe.ca/environment/whats-in-the-water

I could produce some hardware using the Teensy-LC to aid in prototyping if anybody is interested.

What is taking most of my time right now is a low-cost water depth probe, with a place holder here
https://makerspace.com/projects/water-depth-sensor-gauge-wireless-solar-powered-for-remote-streams
which can run by itself data collecting, or plug in to a low cost
Wireless Sensor Network
It uses a basic processor, Teensy-LC
low power MKL26Z with LiFePO4 battery, solar charging and RS485/SDI12 –
initially with a water depth measurements,
and can fit into a 2″ PVC pipe for protection and sealing in a stream.
There is a few places discussing this … so I’m wondering whats a good way of promoting the evolution of specifications for instruments.

with plug’n’play – it will fit into a 3″ plastic pipe for easy protection, solar powered/LiFePo4 and based on a Kinetis Arm (similar to the Teensy3.1 but because of hardware port limitations actually another processor with 128Kram)

So the challenges can be broken into smaller challenges – then they can be solved one-at-a-time.
I wonder if anyone is trying the Teensy3.1/TeensyLC (with Freescale ARM M0 processors) ~ solidly Arduino in a workable footprint.
See also
https://forum.pjrc.com/threads/23660-Low-Power-quot-Green-quot-Battery-Operation-Solutions-For-The-Teensy-3
http://publiclab.org/notes/donblair/08-25-2015/turbidity-001#c12460
http://publiclab.org/notes/neilh20/07-22-2014/water-quality-instrumentation-quality-gottchas

[neilh20]

Hi Dave
Sounds like you have a good idea of what you want to do and the technologies, but to start with the basics.
1) I’d suggest a plan with cost options including what ever time its going to cost in time billing. If there is team install project time with two people per visit for safety and x hours traveling time – the costing analysis changes. If you expect to visit the site regularly and can absorb the wireless network planning then it is a different cost structure.
2) First is to identify locations on the ground (sorry sounds basic but sometimes this step gets missed) and the wireless telemetry options.
2) a cellular radio-site survey – probably first on paper, and then if there is the possibilty of a specific cell carrier to organize having that carriers cell phones and then investigate the site options for actual radio signal.
3) if there is a local building with internet then you could consider a point-to-point system. For a local internet need to investigate how to access that network – sometimes it is easy (eg School, sympathetic property owner) other times the network owner (eg County Water Agency) is challenging to get to the right person and permission to install at top of building. Then need to map the Line of Sight for the radio waves – in valleys its tricky.

One narrow valley I installed in – the property owner knew where there was a narrow alley for Verizon Cellphone – its where he could get his Cellphone to work. And we installed a Verizon system in that alley – which was very unique as almost nobody uses Verizon CDMA systems

Regards

[neilh20]

The LoRa are part of a group of emerging technologies – some that may be built out like the Cellular Network for easy use.
One example is http://www.weightless.org/keyfeatures/5-km-range
Right now they are point to point – that is you have to have both sides of the link – and do Line of Sight analysis. The wireless signals will not go through hillsides.
Cellular providers generally do a regional geographical analysis to attempt to place their cell towers at the highest point so that they can reach the widest number of cell phones.
The big advantage of “LoRa” point-to-point wireless sensor network is overall lower consumed power – the local equipment can manage it better. The disadvantage is that all nodes have to be maintained.
The big advantage of Cellular systems is you only need the end modem – but it has to be in range of a provider and requires much more electrical power.

[neilh20]

Hello Stephanie
Goodluck with it. Thanks for the detail. Out of curiosity what base arduinio are you are looking at.
One way to share the experience is to blog on the stages that you go through.
The challenges – from how to check what works and how to protect it, and how they are overcome are as valuable as the end result.

The Adafruit FON doesn’t state its temperature range – which is usually important for an outside environmental logger, but amazing with the lib
https://github.com/adafruit/Adafruit_FONA_Library – amazing what is being created.
As someone who plays with software/hardware – the technical challenges with software is testing. So personally with this I would
1) Generate a test suite – pick a simple pattern of data reporting,(incrementing number) and then test out the linkages from test unit to reporting. This verifies from unit to internet.
2) For “integration test” – that is checking it works except for the real data – create an air temperature probe – and then stick it out in a realistic situation – just outdoors where it can be easly investigated – and leave it running for a month. This allows all the gremlins to safely introduce themselves and be encouraged to move on.

[neilh20]

BTW its also worth compiling a list of different ways of doing remote long distance RWSN – what works and what doesn’t
One cellular method is to use an integrated Cell phone
https://developer.mbed.org/platforms/u-blox-C027/
And I’ve just seen this that might answer your original question, an Arduino shield for 3G Multitech Socket Modem.
https://developer.mbed.org/components/Multi-Tech-SocketModem-Arduino-Shield-MT/

[neilh20]

Hi Stephanie
Thanks for the azonde.com comment – I started it many years ago – somewhat based on TinyOS.net – which is an embedded CompSci teaching tool.
A better way is to use a REST based reporting.
An example I’ve done using a Rain Gauge (Arduino based) thingspeak.com/channels/8652 (supplied by iobridge.com)
which when using a JavaScript framework looks like this
LiveRainGauge

Wow really interested in your “research interest is in evaluating the effect of engineering hydrologic flowpaths to maintain downstream water chemistry” & “Streams with SC > 500 uS/cm are typically degraded and have significantly reduced biological diversity”
My suggestion would be to collaborate on a significant part of that, measuring the stream SC.
Where would you see the SC probe placed in the water column (see below)?
The challenges from what I understand with SC sensors is the buildup of slime that can impair the readings.
I’m working on a low cost depth gauge – open source.
Part of that could be adapted to a SC probe.
A possible place designed for collaboration could be here..
makerspace.com/u/neilh20/projects/specific-conductance-probe
let me know if this works, but I’m open to anywhere else.

The context: Wireless Sensors Networks (WSN) are challenging and IMHO Riparian WSN (RWSN) are even more challenging, and the technology stack to pull this together is still evolving unless you go for a commercial solution.
I’m seeing if I can solve this technical challenge with the focus on the riparian stream side locations.
– WSN are particularly applicable to long term, sensing over many years with a wide variety of environmental conditions and reliability needs.
– Sensing in the water column is varied and sensors need to be easily changed for both equipment management (failures) and varied traceability requirements. (Some sites require more defined measurement trace-ability than others)
– Depth sensors placement has to be at the bottom of the water column, and best practices are typically 6in/15cm below the lowest level the water is expected to drop to for any stream flow. The primary challenge is the physical sensors themselves – which have temperature dependency and resolution/ accuracy that is challenged with low water heads.

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