Hardware Recommendation: Thermometers/Hygrometers

Hi, Guys and Gals!

I need some advice. So far I have a bunch of venerable Oregon Scientific thermometers/hygrometers connected to Node-RED via rfxcom-hardware getting the 433MHz signal and the contributed node. They run on batts for a long time or even on sunlight, they are unobtrusive and look reasonably good. Some show the current measurements, some only send the data. But newer Oregon devices are somehow not supported by my hardware.

Question: What do you recommend to get a couple (10+) of temperature/humidity readings

  • with low energy consumption, no AC adapter
  • rather cheap, since I want a bunch of them
  • with a high "WAF" (wife's acceptance factor)
  • allowing readings on the device
    into Node-RED?

I got a Shelly Plus H&T (Shelly Plus H&T - All Product - Products - Shelly). I experience a high WAF, it works great so far via WLAN (yes, it runs on batts!) and MQTT, but it is on the pricier side (€35).

Any cheaper, yet reasonably precise OTS solution you could recommend?

Cheers, Uwe

Does the area have WiFi?

One approach is to use ESP8266 boards with a BME280 temperature/pressure/humidity sensor.
The firmware on the ESP can be Arduino, Tasmota, or ESPHome / ESPEasy.
A bare ESP is cheapest but development boards are the easiest to setup because they have USB power and data interface.

Or ESP32 boards (a bit more expensive) can apparently run Node-red https://discourse.nodered.org/t/anybody-experimenting-with-node-red-mcu/71836.

ESPs are low power and have deep sleep so you could run one for months off a battery.

For communicating to Node-red, as always, MQTT. You probably want your own Mosquitto MQTT server.

Edit: Just a note to say that I have been trying to get BME280s working on a couple of ESP8266s with Tasmota today.
The Wemos D1 mini said there was insufficient space to install the right version of Tasmota, the other one doesn't seem to recognise the BME280.
So it's not totally straightforward!

I had one of these as well. It stopped working but I kept the case with the thought of re-working it to use an ESP8266/ESP32 with a better, more modern sensor.

Getting ESPs to genuinely be low-power is a bit of a challenge, especially if you want to try to get 1yr+ out of 2xAA's. That is down to the overheads of Wi-Fi. However, by using LiFePO4 cells with a small solar panel, you shouldn't find it too hard. Fiddly though.

You could also connect a 433MHz transmitter to an ESP or an Arduino and then use it with your existing setup. Turn off Wi-Fi on the ESP to greatly reduce power. If you are OK with electronics, try getting a raw ESP chip rather than one with an on-board USB power regulator as these will use less power again.

But if you want something pre-built and are happy using Zigbee, then Aqara Temperature and Humidity Sensor, REQUIRES AQARA HUB, Zigbee, for Remote Monitoring and Home Automation, Wireless Thermometer Hygrometer, Compatible with Apple HomeKit, Alexa, Works with IFTTT : Amazon.co.uk: Garden may help. Not specifically designed for outdoor use but I've seen a few people commenting that they have done it successfully.

Which don't require an Aqara hub, whatever amazon says. Any Zigbee controller should do.

Do you know if those are better for outdoors than the Sonoff SNZB-02 Those work well indoors for me, but I haven't tried one outdoors. By the way, the Aqara can be got much cheaper than the amazon price there.

Yes, I should have spotted that in the Amazon listing title.

No, I've not tried, I have only been using weather forecast data for outside since my one and only external sensor died. But there were several people who had said they worked for months at least. I would recommend putting an external TH sensor under some shelter anyway to keep it out of direct sun and rain as much as possible.

Sure, Amazon just a convenient link. Though in the UK now, not quite so many realistic options for such things.

The big advantage of the Zigbee devices is that they don't need power.

I have also integrated a Xiaomi Mijia (LYWSD03MMC) via Bluetooth LE in addition to the already mentioned Aqara. However, in Home Assistant, not directly in Node-RED.
For the Mijia I have installed a custom firmware (very easy without soldering or opening the hardware), which extends the functions.

Dear all! Many thanks for your input!
This is my personal conclusion for my inside solution

  • No OTS product using WiFi: Too much power needed (no solar panel inside :wink:, no ugly power brick, no excessive change of batteries) – except Shelly Plus H&T, see below.
  • WAF :woman: rules out my level of tinkering
  • no external service involved
  • MQTT
  • Stylish Shelly Plus H&T via MQTT where reading the device on te spot is needed
  • I will explore Aqara & Zigbee.

Regards, Uwe

I am using enocean sensors. These use photovoltaik.
Downside is that they cost about 50+€.
[Nod On STPH-2-1-05 Enocean]

How do you get the 868MHz into Node-RED?
Cheers, Uwe

ZIGBEE works with this frequenz.
If you are going to use ZIGBEE I recommned a sonoff Adapter
(SONOFF Zigbee 3.0 USB Dongle Plus ZBDongle-P)
Works perfectly for me.


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