Author Topic: Collecting Temperature Data  (Read 682 times)

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Online bostonmanTopic starter

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Collecting Temperature Data
« on: March 14, 2019, 02:55:08 pm »
I'd like to use a Raspberry Pi (or similar) to collect temperature data on water pipes as the water moves through. So the sample rate would be fairly quick, averaged, and then given at maybe a one-second rate. As for a sensor, either a thermistor or a temp IC.

Ideally I'd like to monitor several locations spread out across approximately fifty-feet in various directions. I'm having difficulty coming up with a solution that is: cost effective, one cable with all the sensors in series instead of a separate cable from each sensor back to the Pi, and a method of getting DC (or AC) power to each sensor.

I've looked at an I2C bus, but got caught with getting power to each board, and also not having to make separate PCBs for each location I wish to monitor.

Any ideas would be greatly appreciated.

 

Offline schmitt trigger

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Re: Collecting Temperature Data
« Reply #1 on: March 14, 2019, 03:14:14 pm »
One single cable for all the sensors? There is the 1-wire system which as its name mentions, does not require a separate power line. However it is slow and has worse performance than I2C with respect to receiving reliable data from remote sensors. I have never studied its addressability capabilities.

I would suggest using a far more robust protocol, like CANBUS or RS485. Unfortunately this means both power and ground wires, plus a pair of differential signals.
 

Offline Hemi345

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Re: Collecting Temperature Data
« Reply #2 on: March 14, 2019, 03:28:00 pm »
I've had good luck with Maxim/Dallas 1-wire sensors. There's a document that explains the various topologies for connecting multiple sensors and all the considerations for pullup value and line capacitance. Take a look at the DS18B20

[Edited to include link to sensor I've had good experience with]
« Last Edit: March 14, 2019, 04:22:27 pm by Hemi345 »
 

Offline Hemi345

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Re: Collecting Temperature Data
« Reply #3 on: March 14, 2019, 03:29:35 pm »
 
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