I’m looking for an IoT setup that will monitor temperature and humidity both inside and outside of a remote building, around 40 feet apart. It looks like a Pi with the Grove Base Hat and the DHT20 sensors are almost what I need, but if I’m not mistaken then a pair of DHT20’s would address clash and I wouldn’t be able to communicate reliably across that distance. What is an available Pi-based solution that can reliably read two temperature sensors and two humidity sensors from 20 feet away?

*Wireless is not an option

  • 2
    shopping questions are off topic here ... please edit your post ... also, any solution would work with other microcontrollers, so your question is not Raspberry Pi specific
    – jsotola
    Aug 6 at 20:01
  • I don't want to use dupont jumpers, so that almost certainly narrows it down to hats and makes this Raspberry Pi specific. I don't see that my question is shopping-related either, outside of my requirements that the device is available (not discontinued etc).
    – BoThompson
    Aug 6 at 20:07
  • 1
    that almost certainly narrows it down to hats ... your information is not quite correct ... other microcontroller systems use daughter cards, they just don't call them "hat" ... dupont jumpers are not a requirement in any system ... as for the shopping question, you can ask for a confirmation that a device exists, then go find it ... but you can do the search without asking first
    – jsotola
    Aug 6 at 20:14
  • Well, my search was fruitless, hence the question. If this is an improper place to ask by your estimation, kindly suggest an alternative forum.
    – BoThompson
    Aug 6 at 20:59
  • you could use an I2C multiplexer
    – jsotola
    Aug 6 at 21:09

My solution is to add some more smarts, additional controllers. You could use some inexpensive Raspberry Pi zeros or even cheap Arduinos. This will get you started with a system you can expand easily. I would connect the sensors to the zeros and add a CAN link. CAN is time proven reliable and will operate over long distances. MCP2515s are inexpensive and do most of the hard work for you.

The communications can also be accomplished by WiFi, LoRa or many other forms of RF communication. There is a lot of information for DIY using either of these with the Pi or Arduino.

However since you are looking at cabling between locations consider using a 4 conductor cable where 1 pair supplies 24VDC and the other pair is CAN. Using a SEPIC (Single-Ended Primary-Inductor Converter) converter (I am partial to them) at each zero (this cleans up the power and keeps the current on the power feed down) you should get a very reliable system without a large cash outlay.

This network gives you a lot of future capability such as alarms and controls at the remote buildings etc. You can expand it at any time by just adding another node. This keeps the sensor lines short and reliable.

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