help needed with multiple temp sensor data logging project

  • I am needing to data log water temp multiple fish tanks plus air temp

    I had bought multiple wireless weather station devices that were meant to work 100m range but only work 6m range

    Ideally, i would like the probes hard wired with the Arduino data beeing collected wirelessly

    if anyone could direct me to parts/guide needed for a setup that could be scalable it would be greatly appreciated

    for now, I need to compare temperatures of tanks within 10m of each other

    it looks like its down to

    domoticz vs home assistant vs openhab

  • Mod

    Welcome to the MySensors community @MasterCATZ

    You'll find information on controllers at

    The overall MySensors getting started guide is available at That guide also has information on the number of sensors and sensor nodes that can be connected in MySensors.

    The build page for an example temperature sensor is at
    Waterproof DS18B20:

  • Do you have and idea of what temperature sensors you will use? The 1-wire ds18b20 have reasonable accuracy, there are inexpensive versions that are weatherproof, and probably submersible. They can all reside on a single bus, so you would need 10 of them and 1 arduino (plus some wire).

    I think the dhtXX and sht sensors would require some waterproofing, but may work.

  • @wallyllama I suspect a little more layout detail would assist, multiple = ?
    If you had 100 5m wide tanks above ground in series at 3m gaps under a steel roof needing read every 30 seconds versus 99 5m wide below ground tanks laid out as a square grid with 3m gaps the recommendations will be different.... Define the question so the answer is less a SWAG....
    What do you perceive the advantage is of wire V radio? If you need to change batteries every 2 years is that a headache?

  • @zboblamont the otiginal poster specified hard wired for the sensors, that made me think 1-wire, if it is truly 100 tanks, I would probably put 10 tanks per arduino/nrf, the basic mysensor temperature node mentioned above with a bit of modification to allow multiple sensors would do the trick. The arduino ide has examples that enumerate the sensors and poll them. There are some threads here in the forum where people have done that, and it may be just copying their code would suffice

    I'd search "reliable 1-wire networks" there are guides that help with the distance, and how many per network etc. Better to read the original than my summary on that.

  • @wallyllama Indeed, that is point, the OP stated hardwire as the 'ideal scenario", but without giving reason. Depending on the tank orientation, hard wiring a 9 group of temps to 10 Arduinos RFing the output to a central receiver would probably be an elegant solution. But if there are 20 tanks 1m wide at 1m gaps, 2m long the ideal solution would be different....

  • Thanks for the replies
    didn't think I mentioned how many tanks 😛
    but while we are at it
    3x 20kl tanks ( all grouped together about 50m away from others )
    50x 1kl tanks ( only 14x row being monitored at this stage )
    112x 200L tanks ( 12mx6m fish room )
    excluding sumps/biofilters etc

    most tanks outside are within 10m of the fish room

    having wireless just means having to find a way to power the devices
    ( been there tried that with solar powered ones pre made. nothing but unreliable)

    and a broken wire is easier to diagnose for faults

    I just don't seem to have any luck with wireless I have ones here rated for 100 - 300m yet lucky to get 10m out of them

    sensors accuracy not so critical just need to be waterproof and handle 6m deep submersion, what I am mostly wanting to work out is if tanks are going to do better inside a greenhouse or not

    and wanting to trial other ways of using heat exchangers
    ( ie the old black coiled up polly pipe trick )
    to lower heating power usage

  • @MasterCATZ Thanks for that - It's the physical distance between which will determine whether the daisy chained sensors will work, but how they can be adapted for 6m pressure head is a separate puzzle for now. You clearly have recirc pumps and filters, so would a surface mount on the incoming pipework be more closely grouped and accurate enough?

    I would not so quickly dismiss radio solutions through your own unfortunate experience, there are multiple examples on this site of superb designs for battery powered radio devices lasting months and years reliably.
    Moteinos with deep sleep between activities can give over a year on AA batteries, I just bought a bunch of Whisper Nodes which may last 2 years on two AA alkalines, sending back data by radio every 4 minutes or when triggered, in some cases other every hour using a RTC.

    If surface mounting sensors on metal pipe at pump manifolds is not viable, how about surface mounting on the tank wall if steel tanks?

  • No metal pumps around here everything is air operated and plastic pipes

    it's only the 20kl tanks that have 6m depths, the others have 3m deep sumps
    ( pretty much the further down into the ground the more stable the temperatures so I run far amount of plumbing deep underground, that and I use airlift pumping techniques )

    It is mostly the 200L breeding tanks I want to do
    they are only 46cm deep
    and contain the Tropical Fish I am trying to keep tabs on
    all pretty close to each other on racked shelves

    I am just unsure if my wireless issues are from all the water around here or not , ages ago I was looking into XBee, but that was about as far as that got

    the building is only wooden frame with plastic cladding with multiwall polycarbonate. I don't see that affecting wireless, however my Fitzbox NBN Modem is always complaining about radar jamming signal's, so it could just be the military base that is not to far away

    looked into "reliable 1-wire networks" it seems most users had problems over 30m but it does seem it can do the distance of 100m if cat5 is used, I may as well use the cat6 I have here

    I will have to go back through my browser history I had found a probe that was around 10+m long that was waterproof

    does seem quite cheap however

    strange now all I see are the DS18B20 but at least i know they make 15m long probes

    mZPEGGFSoBX79XQ4RR57Mog" rel="nofollow">ⓂmZPEGGFSoBX79XQ4RR57Mog

  • @MasterCATZ Ok on all that... Air lifts in plastic pipes are pretty gentle, reliable and oxygenate the recycle. It was just the possibility to measure surface temps instead of water temps I was thinking of.

    DS18B20s have unique address codes as was mentioned above, so you can have a bunch of them connected on a single line in a group, a program checks and notes response from each one in turn, strings the results together and fires them off to a central gateway. I suggest that trying to avoid grouping these on radio nodes and trying to hardwire everything will bring you a world of pain....

    Radio antennae need line of sight ideally to communicate easily at UHF although will go through walls and timber constructions with minimum attenuation, just raise the antennae above racks and tanks, you will get reliable comms no problem with a half decent quarter or DIY dipole. If you look at a spot where tanks are within your 30m parameter then install a radio node to cover all of those in the footprint is a much simpler and cost effective solution.

    I looked initially at 2.4GHz use, but settled on 433MHz for low power, longevity of standalone power, less troublesome protocols, and greater penetration through masonry. Well away from my and other local Wifi routers also...

  • what is your recommendation for the wireless hardware

    "Serial WiFi Module ESP8266 module ESP01"

    are what I have tried in the past with poor results

    I have been thinking I could make a wireless module, disconnect the sensor from 1 wire and I could plug the probes into wifi when I need to?

    how do I go about Daisy chaining the probes
    are there any simple splice crimp connector out their?
    ( might use telephone cables or ribbon cables as I don't think I should use RJ45 just incase someone mistakes as a LAN port )

    I did come across this

    but to me, it just looks like its purpose is just to add the pull-down resistor?

    does every probe need the resistor or is only 1x needed?
    also any probes for PH that work using 1-wire? or water level sensor?

  • how do I go about Daisy chaining the probes

    1-wire devices (actually 2 or 3 wires) are designed to be linked in a daisy chain, or really just connect in parallel. The wires are data, ground and +5v. The chips can run off parasite power, they charge when you put a "1" on the data line. Parasite power will affect speed, length and reliability of reading. Do a search on "building reliable 1-wire netowrks". I'm far from an expert, and there are a couple of sources that explain it all nicely. One link is on maxim's site, and I dont remember the other, they cover most of the same information.

    In your case you'll want to run the +5v wire if at all possible, you may want to run a hub with switching, or it may be easier to run several separate busses, with just a few sensores on each, you could still wire them to 1 arduino, just use 1 digital pin for each. It will make the software more complex, so you may want 1 arduino for wvery 3 or 4 tanks. Technically you can get away with all of them on one bus, ( aka run 3 wires all around from one tank to another.

    Cheap ascii graphic ( hopefully it helps)
    Arduino _____________________________________________ +5
    ===================================== data/gnd
    ||| ||| |||
    ||| ||| |||
    Sensor1 sensor2. Sensor3 ....
    Tank1. Tank2. Tank3

  • @wallyllama awww the spaces on my cheap ascii graphic got crushed.

  • @MasterCATZ 1-wire hubs are active, sort of like usb. You dont want your one wire network to be a star topology. You want some thing like railroad tracks, long wires(rails) with short connections to the sensors(ties). The guides i mentioned really are worth a read before you plan too much.

  • Other answers. 1 resistor per 1-wire network.

    I believe you can still get a/d converter chips, they could probably be used to read an orp or ph sensor. Water level could possibly be read with a capacative sensor, but you are going run into your power problems again.

  • Ok that's what I wanted to know as I did read here
    50mm was as long as you could go

    however, how does that work if the probe wire is long?

    would I be better off making my own probe's with 6 wires with
    In / Out ? that then links to the next part of the daisy chain ?

  • The ds2450 adc is out of production. The ds2438 battery monitor is ehat you'd have to use.

    This person was going to use the adc, but ill bet the batter monitor could be made to work.

    For connections, a 3 port rj11 might work, in from previous tank, out to next, and one to the tank sensor. I think if you keep the line to the tank under 1meter you are ok, but i have never built a network as long as you are proposing.

  • Maximintegrated

    Read this, there is a formula for what they call weight, and they talk about stubs. That would be the part from the main bus wires to the sensor.

  • @MasterCATZ
    I have no experience of the daisy chaining of sensors but as wallyllama has explained, this is pretty much my understanding of the technique, and I'm sure I read recently about the difference between parasitic power connection and normal fairly recently in a post.

    MySensors was originally built around the NRF24 2.4 GHz transceivers as I understand it, but there has been considerable interest and development with the RFM69 series transceivers which have better range in the 433MHz area. I suggest you look at Moteino and the Whisper Node I mentioned earlier as they are well thought out designs, radio module incorporated, low power consumption, compact, etc. and seem reliable. There are multiple alternatives folk here have utilised in the uhf bands varying from the ultra cheap chinese no-name to almost professional grade transceivers, it rather depends whether you want off the shelf units with loads of support or want to experiment with fine soldering. I didn't, as too old and shaky for that, so went Whisper Nodes, and just building them and playing with them now in advance of the Gateway arriving.

    Some things you may wish to consider are temperature transients in the tank so you can establish the ideal sense point, how often you want the data updated (hourly, every ten minutes, every four seconds) as this may need a RTC, collision management for data coming in, and whether the node needs physically protected against the environment.

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