help needed with multiple temp sensor data logging project

[zboblamont]

@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...

[MasterCATZ]

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

http://www.ebay.com.au/itm/DS18B20-Waterproof-Digital-Temperature-Sensor-With-Adapter-Module-for-Arduino-WS-/182526807558?hash=item2a7f720e06:g:lW4AAOSw-itXp~d7

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?

[wallyllama]

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]

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

[MasterCATZ]

darn you beat me before the edit

http://www.hw-group.com/products/sensors/Temp-1Wire_en.html

has got me thinking about telephone hubs

http://www.ebay.com.au/itm/1pc-RJ11-Jack-5-Ways-Outlet-Phone-Modular-Line-Adapter-Splitter-Connector-/311408926547?hash=item48816b1f53:g:iVsAAOSwyQtVrK8u

[wallyllama]

@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.

[wallyllama]

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.

[MasterCATZ]

Ok that's what I wanted to know as I did read here
http://www.jon00.me.uk/onewireintro.shtml
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 ?

[wallyllama]

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.
Reefcentral

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.

[wallyllama]

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.

[zboblamont]

@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.

Radio
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.

[MasterCATZ]

RFM69 does look promising even if
I have to power it

[MasterCATZ]

looks like I will have to make my own sensors that Daisy chain directly off the sensor

https://edwardmallon.wordpress.com/2015/03/01/using-ds18b20-sensors-to-make-a-diy-thermistor-string-pt-1-the-build/

[MasterCATZ]

so what I think I will do is

use a trimpot at the start so resistance can be adjusted as sensors/length are altered

cat5 wiring

Dry end has 2x rj11 ends
*example
rj11 (in) pins 1,2,3,4
rj11 (out) pins 5,6,7,8

Pin 1 (White/Green) - Power return or ground
Pin 2 (Green) - +5V
Pin 3 (White/Orange) - Power return or ground
Pin 4 (Blue) - DQ (data in)

Pin 5 (White/Blue) - 1-Wire return or ground
Pin 6 (Orange) - +5V
Pin 7 (White/Brown) Power return or ground
Pin 8 (Brown) - DQ (data out)

all wires join onto the DS18B20 and waterproofed

then up at the dry end use rj11 joiners, they can be pulled apart and have resistors added if needed and if I need to take a sensor out of the daisy chain, it is just a matter of bypassing a joiner

http://www.ebay.com.au/itm/RJ11-6P4C-Female-Modular-Telephone-Cable-Wire-Straight-Coupler-Joiner-White-/111725356245?hash=item1a0359a4d5:g:miQAAOSwWxNY2l0I

or I just do the STUBS thing 100-150Ω resistor inside a 3 way splitter and have a normal premade waterproofed sensor used with rj11 connector

http://www.ebay.com.au/itm/10pcs-RJ-11-RJ-14-Phone-Line-Cable-Coupler-3-Way-Splitter-Connector-Adapter-/290986642163?hash=item43c027caf3:g:LD4AAOxySy9SRSLm

either should work in the fish room tanks are on racks stacked to each other

so how would I go about doing a 1-wire breakout, as each rack would be pushing the length and I have 14x racks ~3m long 4 tiers
I might be possible to do the daisy chain per 2 racks
is their a way to do it without using multiple Arduino , is there some hardware that would allow multiple runs of 1-wire ?

[MasterCATZ]

another thing does anyone know if putting capacitors in the daisy chain will cause any issues?

I figured haveing a capacitor near a sensor would help keep the power stable?

[wallyllama]

There are 1wire "hubs" that would help, they basically turn on or off parts of the network, so each run could be the max distance.

Each network would need only 1 digital pin and resistor, i think you could define multiple pins and do a onewire.begin for each (using different names each of course) i think you would run out of memory or clock cycles before you ran out of pins even with a pro mini.

Using a dedicated 5v line is probably better than a capacitor and parasitic power, especially with long runs and lots of sensors. Unless you can live with really slow polling times. With the complexity you are talking about, I wouldn't be surprised if takes a couple of minutes to poll everything reliably with parasitic power. If it works (i havent tried it) using several pins on the arduino, each controlling a 1wire network might help out considerably. You could service 1 network, while the others are being "charged".

[wallyllama]

If you search "1-wire hub", there are premade options, and diy.

[MasterCATZ]

thanks for your guidance
parts arrived yesterday and just got the probes reading

how ever I could not get OWFS to work,
https://www.domoticz.com/wiki/1Wire

sudo i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

but using /sys/bus/w1/devices
they are there

cat w1_slave
a2 01 4b 46 7f ff 0c 10 49 : crc=49 YES
a2 01 4b 46 7f ff 0c 10 49 t=26125

edit

actually quite happy, using 5v and daisy chained a heap of cat5 cables together for testing, over 100m all working good

[wallyllama]

@MasterCATZ :smiley_cat:

[zboblamont]

@MasterCATZ I'm following this with interest as looking at a WAY smaller scale use with the small 3 legged 18B20 to give individual room temperatures in the house, 4 upstairs, 6 downstairs.
Had originally considered individual room nodes, but this seems a slightly simpler solution (other than lifting parts of the upstairs floor).