Another “what should I buy” thread

I want to measure:
Solar production
10 individual circuits on breaker
7 rooms for temperature

What hardware do I need?

Unrelated question: can the temp sensors be powered by PoE instead of battery?

Well, for the 7 rooms temp sensors, I’d buy 7 Dallas Sensor and connect them to 7 ESP-01. The ESP-01 is very basic, very cheep, has Wifi integrated and for sure, with an adapter, you can power them by PoE.

For the rest, if you don’t have any electric meter, you could achieve it with 2 Arduino (with CTs, …) with 2 ESP-01 for sending data over Wifi. An Arduino has 6 A/C converters, and you need 11… so 2 of them.

As a central server, I’d use a Raspberry.


Thanks for the quick reply! I’ll keep reading and look into this setup. It’s quite a lot to digest but thanks for pointing me in the right direction.

But the bigger Arduinos have more. I suggest you look at Boredom projects . There, there is a design based on our emonTx but using a more powerful processor (still in the Arduino range). That will do (as it stands) exactly what you need for the voltage and currents. His software won’t do for you - it’s 3-phase, but you can easily extend the examples in the ‘Learn’ section here that use emonLib to your 11 inputs.

Indeed it is. But according to boredman, it’s easy to adapt it for use with single-phase circuits:

RE: Home Energy Monitoring System — rjsc2000 2016-01-30 21:22

I’ve bought a due board and would like to give it a try. But i have only a single phase and not 3 phases. I haven’t seen the code yet, but can you tell me if it’s easy to change it to single phase?


RE: Home Energy Monitoring System — boredman 2016-02-09 08:04

Yes, very easy. All you have to do is to use the same phase constant 1 in all instantiations of emon object.
Ex.: emon[0].voltage(…, …, …, 1);

Ref: Home Energy Monitoring System
(search the comments for the words single phase)

The emonTH would do the job, wireless and battery powered, but is a relatively expensive solution.

The question is how far apart they are and if you want cables or wireless. As suggested you can use Dallas One-wire devices (the ubiquitous ds18b20) and an ESP based device (my preference is a genuine Wemos D1 Mini) and I’d suggest Tasmota for the collection as I find that Wi-Fi implementation to be the most robust. If cables are OK then just one ESP device for all, else one per temp sensor but that does then need mains power.

You will need to process the information from Tasmota to get it into emonCMS - my preference is Node-RED. ESPHome has a different way of sending data by MQTT so you can specify the topic for the data more easily and pass it directly to emonCMS.

If cables are an issue, there are some Bluetooth temp sensors around but reading them can be hit or miss. I’m currently using GitHub - custom-components/ble_monitor: BLE monitor passively monitors BLE sensors (Xiaomi, Qingping, ATC, BlueMaestro, Brifit, Govee, Kegtron, Moat, iNode, Yeelight, RuuviTag, SensorPush, Teltonika and Thermoplus) within Home Assistant and that is proving to be very reliable (although I did add an additional BT dongle via an USB/RJ45 extender).

Thanks all! Lots to read about now. I’ll check back in with any further questions. I am fishing Cat6 through my house right now and it would be fairly easy to add some runs, plus I want to plan my switches around what might connect. If I can power everything with PoE I’d be golden. Otherwise, I’d have to call an electrician to bring me outlets where I need them - I have no plans to get shocked again.