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@neilh20
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Hello Dave, thanks for sharing.
I had thought of getting the device, because of the price, so interesting.
The issues I saw is that it has two sources of analog error and unquantified temperature co
Hello Dave, thanks for sharing.I had thought of getting the device, because of the price, so interesting.
The issues I saw is that it has two sources of analog error and unquantified temperature coeffocient for each source of error.
Every “analog” device typically has a temperature dependency, This would be the depth sensor itself, which will vary the reported depth based on the varying temperature of the water. Typically small if the temperature is stable as in underground water measurement.
The second analog error – which is the current transformed to the voltage. This resistance will vary based on the air temperature. Resistor need to be selected and stated for the their temperature variation. There are resistors that have a low temperature coefficient. So the device from Seeed should state what its temperature coefficient is, but I couldn’t find it.
So just an observation, and thanks again for sharing.
Hi James, if you have the spare jumper cable sockets you could try it and it probably will work.The challenge is the Mayfly doesn’t have a lot of capacitive buffering and the LiIon battery per
Hi James, if you have the spare jumper cable sockets you could try it and it probably will work.The challenge is the Mayfly doesn’t have a lot of capacitive buffering and the LiIon battery performs that function. It might be more reliable to have a battery on each Mayfly and run the solar panel to both. Of course the boards need to be kept physically isolated so they don’t connect electrically.
My node is using a LT500/SDI-12 and a Keller Acculevel/Modbus on Mayfly 0.5B https://monitormywatershed.org/sites/TUCA-Na13/
Its using a release based on 0.28.5 ~ https://github.com/neilh10/ModularSensors/releases/tag/v0.28.5.release1_210711 and it is built as a working release in https://github.com/neilh10/ModularSensors/tree/v0.28.5.release1_210711/examples/tu_xx01 with src/ms_cfg.h_LT5KA_lte copied to ms_cfg.h
Wow thanks so much for sharing, and no problem with your English. I’ve been in that situation where its difficult to debug ModularSensors/Mayfly as the software implementation using time loopsWow thanks so much for sharing, and no problem with your English. I’ve been in that situation where its difficult to debug ModularSensors/Mayfly as the software implementation using time loops is so time sensitive.Are you planning on using a git to store the programs with an open source license? Its very nice if you do and gives some confidence in being able to do crowd sourced testing and feeding back how it works. 🙂
Just wondering if you are using your program with the Mayfly implementation?
One issue to keep in mind if using the Mayfly, is that the SDI-12 is specified electrically as 0V to +5V, and the Mayfly as SDI-12 recorder/host/server implementation has a reduced electrical interface to only do 0V to +3.3V. This makes it easy to implement. However it can mean that the SDI-12 sensor equipment doesn’t detect the incoming packet. I’ve seen this for the Insitu LT500 equipment ~ or at least I got a non-response from some older equipment and assumed that was the reason. Similarly with the Vegetronix SDI-12 analog sensor that has been tested to the SDI-12 specification, it doesn’t respond. An earlier version of the Vegetronix SDI-12 analog sensor does respond, but that version didn’t have the CRC implementation.
You solve the electrical interface by using the TekBox TBS03 (or at least hopefully it covers it), though I wonder if it also reports packets that are out of electrical specification?
@rogers1313 – its a good “engineering question”. speaking as an electrical engineer and some one that has blogged on understanding traceability, measurement range, measurement reso@rogers1313 – its a good “engineering question”. speaking as an electrical engineer and some one that has blogged on understanding traceability, measurement range, measurement resolution. measurement accuracy and total error band of measurement being different aspects of the measurement.In short the Hydro 21 has calibrated measurements that can be read digitally (SDI-12) with defined accuracy.
Data sheet for Hydros 21 https://library.metergroup.com/Integrator%20Guide/18468%20HYDROS%2021%20Gen2%20Integrator%20Guide.pdf
A more complex answer on accuracy is what are you trying to measure accurately?
See Hydros 21 CTD ” 3.1 specifications” and I queried the manufacturer about some aspects of the specifications (and afterwards the specifications where updated and easier to understand). The nice part of the Hydros 21 CTD is the “low cost”, SDI-12 interface, combined Depth, Temperature and ElectricalConductivity in one physical unit.
Water Depth units are mm an accuracy is ±0.05% of full scale at 20 °C, for full scale of 10,000mm that is +/-5mm @ 20C
However there is the real world “NOTE: Depth measurement accuracy assumes no abrupt temperature variations.”
No abrupt temperature variations is not defined – and I asked them about it – is that a 1C shift in 15minute period, or 10C shift in 15minute period. If you are measuring the last 100mm of a stream drying out in a mountain pool, with say a 10C temperature diurnal change then there may be a temperature dependency on the measurement. If you are measuring the way a water body peaks at 10m (33ft), from 1m(3ft) or well water depth changes its probably good accuracy. The engineering challenge for this type of water depth sensor is that the pressure sensor that converts water depth to an electrical parameter is highly optimized resistor, which has a large temperature coefficient. Generally speaking for accuracy in the component sensor, its usually stated as between 10% and 90% of range – but this is complicated engineering. Sufficient to say again, if you want to measure the last 100mm of a stream drying out which we do in California accuracy is challenging.
Temperature is one of simples aspects of measurement and reasonable accuracy at +/1C and resolution at +/0.1C. Units are C
EC is stated as accuracy ±0.01 dS/m or ±10%, whichever is greater, Resolution 0.001 dS/m
There are some users on this board who have extensive experience with CTD21, however the people I work with in drought areas with large temperature changes don’t use it, and I’ve only looked at the specs, never tested a unit.
When it comes to sensors I have tested for accuracy and temperature dependency a number of low cost sensors, and also Keller Levelgage (lousy temperature dependency) Keller Acculevel (better ) and the gold standard that TU Oakland uses Insitu LT500. I’ve also returned some LT500 to the manufacturer for further calibration of the temperature coefficient as it was outside their stated range.
https://www.envirodiy.org/comparison-temperature-dependency-in-situ-lt500-and-keller-nano-level/
https://www.envirodiy.org/measuring-low-water-in-streams-accurately/
The LT500 has the ability to define the units, as well as few other parameters.
Hope that is useful – BTW I’ve also started a thread on using Scaling Modular Sensors https://www.envirodiy.org/topic/geographically-scaling-modular-sensors/
(edit : thanks Heather this is post had got stuck) @rogers1313 great to hear your project (from your posts in the (edit : thanks Heather this is post had got stuck) @rogers1313 great to hear your project (from your posts in the https://www.envirodiy.org/topic/mayfly-v1-1-technical-questions-forum-thread/#post-17333)– thanks for filing your profile https://www.envirodiy.org/members/rogers1313/profile/
I’m similar EE/and FirmWare – https://www.envirodiy.org/members/neilh20/profile/ – youre welcome to email me dreictly, but this is also a good place for discussing how to deploy.
Matt is also deploying for TU https://www.envirodiy.org/members/mbarney/profile/
This thread may be of interest – I’m targeting my fork for easy deployment and reliable delivery of readings .I’m scaling some systems for Tu N California, and documenting some of it through this (but an open source wip).
https://github.com/neilh10/ModularSensors/wikihttps://github.com/neilh10/ms_releases
https://github.com/neilh10/ms_releases/wiki
https://github.com/neilh10/ms_hardwareFor low cell phone service I’m using an android app “Phone Signal” https://inpocketsoftware.com/phone-signal-cell-strength-overview/ for doing a survey.
A note, IMHO the core https://github.com/EnviroDIY/ModularSensors works for where there is reliable phone service – excluding some 90% of potential coverage range where the cell signal may be marginal.@rogers1313 Some other links .. I’m trying four links to see if it passes the spam filter ..
https://githu@rogers1313 Some other links .. I’m trying four links to see if it passes the spam filter ..
https://github.com/neilh10/ModularSensors/wikihttps://github.com/neilh10/ms_releases/wiki
https://github.com/neilh10/ms_releases@rogers1313 great to hear of your project from the technical questions thread.
This thread on scaling may be of interest.
I just posted a lot of links for scaling systems, and I forgot that env@rogers1313 great to hear of your project from the technical questions thread.
This thread on scaling may be of interest.
I just posted a lot of links for scaling systems, and I forgot that enviroDIY doesn’t allow too many links in messages. (spam protection I guess).
I’m scaling some systems for Tu N California, soley stage gauges at present. If you would like some pointers I’m happy to post some links
https://www.envirodiy.org/members/neilh20/profile/@rogers1313 my systems only have the Yellow led ON when actually charging. If the battery is charged, not charginng then it is OFF. The description in “Section S”, beneath the pics https@rogers1313 my systems only have the Yellow led ON when actually charging. If the battery is charged, not charginng then it is OFF. The description in “Section S”, beneath the pics https://www.envirodiy.org/mayfly/hardware/details-and-specs/ saysA yellow LED (labeled CHARGE) will light anytime the battery is being charged. Once a battery is fully charged, the yellow LED will go out, indicating that charging is done.
For the battery, seems to me there are two engineering approaches, specification and characterization.
For the specified battery 4400mAh https://www.adafruit.com/product/354
which has a listed data sFor the battery, seems to me there are two engineering approaches, specification and characterization.
For the specified battery 4400mAh https://www.adafruit.com/product/354
which has a listed data sheet from the manufacturer – https://cdn-shop.adafruit.com/product-files/354/C449_-_ICR18650_4400mAh_3.7V_with_PCM_20140728_APPROVED_8.18.pdf
it has a defined “Operating Temperature” of Charge: 0-45C, and Discharge -20 – 60C.
If you go outside those parameters, for too long (!) – some may still operate – but now its characterization as to how many will operate.
Of course manufacturers do characterization upfront on their products, to be able to come up with a specification they stand by across all that product range.@mbarney, thanks for the settings. What was the sim supplier that you used – a Verizon direct, or an MNVO like REVX.I did get an email earlier this week from SimCom that there 7080G was no
@mbarney, thanks for the settings. What was the sim supplier that you used – a Verizon direct, or an MNVO like REVX.I did get an email earlier this week from SimCom that there 7080G was now certified by Verizon, so good to know it works 🙂
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