How can I monitor the temperature over time in several rooms?

February 25, 2022 12:15 AM

I would like to monitor the temperature (humidity would be a nice bonus) in multiple places in my house over time, partly out of curiosity and partly to gather data I can use to help decide on the schedule for my thermostat. I want access to the raw data but a built-in way to see a graph of it would be great too. What are some ways I could do this?

I have Windows and Mac computers and an iPhone. All of the locations I’d like to put the sensors have WiFi coverage. I’m open to buying something like a Raspberry Pi if I need something to act as a server (though it seems like they may currently be out of stock in a lot of places). I’m technical and don’t mind a bit of setup/configuration, but don’t have a lot of free time at the moment so would prefer to avoid this being a major time sink.

My original thought was to just buy a Raspberry Pi and a temperature sensor and write my own code to collect, store, and graph the temperature info, but I realized there may be something easier and better out there that will do what I need. Also to monitor multiple places it would get expensive to buy a separate Pi for each one.

I suspect that some off-the-shelf solutions may be targeted at home automation, but this is an area I haven’t had a need to dig into yet so I’m very unfamiliar with it. I currently have a few AirPlay speakers set up in HomeKit but that’s it as far as home automation stuff goes.

I would prefer to avoid making any choices for this project that lock me into using a particular ecosystem going forward. (Not sure if this is a concern or not? Just want to avoid making decisions for this minor project that I might regret if I want to do more important home automation stuff later.)

I do want access to the raw data from the sensors. My first preference would be to have the data stored locally so I have control over it, though I’m open to a cloud solution with a good API. It would be great if there was also a built-in way to see a graph of the data over time and compare different locations (but if need be I could do this myself from the raw data).

My budget for this is up to a few hundred dollars, maybe more if there are pieces that I’m likely to use for other things in the future (e.g. a Pi to act as a server, or some kind of hub that supports other sensor types I might want in the future, etc.).

Thanks for any recommendations.

posted by unus sum to Computers & Internet (17 answers total)

I use Home Assistant running on a Raspberry Pi 3B+, with a HUSBZB-1 zigbee/z-wave dongle talking to Aeotec MultiSensor 6s and TriSensor 3 z-wave sensors throughout our apartment. The MultiSensor 6 is nice because it can be connected to any USB power adapter and sample at a higher rate (you can set up a bunch of parameters via Z-Wave including how often it reports and how many degrees' change are needed before reporting. Home Assistant stores all my data locally.

There are probably cheaper options than the Aeotec stuff for the sensors (maybe something Aqara?), but eh, they work for me!
posted by Alterscape at 12:30 AM on February 25, 2022 [1 favorite]

InkBird sensor, waterproof, can be put in freezer or fridge, but works fine in ambient temp too. $15 on Amazon. Mounts to almost anything via its internal magnet, talks to Bluetooth to the app on your smartphone, and logs as well (on your phone). They also have one with humidity sensor for $20. NO Gateway needed. It does NOT connect to a smarthome hub.
posted by kschang at 1:31 AM on February 25, 2022 [2 favorites]

There’s some free software called mycodo, that was originally written for environmental monitoring and control of mushroom fruiting chambers. Runs on a raspberry pi, works with a number of cheap sensors. Does require some DIY.
posted by Jobst at 5:18 AM on February 25, 2022

I did exactly this early last year to monitor a ceiling that had collapsed. I was inspired by and followed the directions in this Medium article, although I got the best information the video as produced by Elizabeth Adams.
It uses Raspberry Pi Zero W, which is Wifi enabled and costs about €11.00, and the temperature/ humidity sensor BME280 which I found for €8. You'll need some cables and housings and such but should be able to get them together for less than €50 each.
I installed 5 sensors and am monitoring it through the recommended Initial State data visualization service which costs about €10 per month.
You are welcome to send me a message if you would like.
posted by Tunierikson at 5:19 AM on February 25, 2022 [2 favorites]

There is a lot of good information about different weather stations (DIY and also out of the box) at https://www.wxforum.net/.

I ended up replacing an old AcuRite system with Ecowitt products (specifically GW1102 system along with 3 extra temp gauges) and have been happy. If you create a free account at www.ecowitt.net, I believe you can view some of the user's weather data (if they have it open to the public) before you purchase anything, to have an idea of the weather data available. Once logged in, from the top menu select 'weather map'.
posted by bCat at 6:27 AM on February 25, 2022

I bought several inexpensive Govee sensors that track humidity & temperature, and give good historical data in the iPhone app:

Model H5075, available at Amazon in a three-pack.

I also have HomeAssistant running on a Raspberry Pi 3, which can talk to these sensors, but it's a pain in the neck to set up -- and the iPhone app shows really good data (as shown on the product page here). However, if you want to collect the data and crunch it, the HA platform and the free integration for thee items will definitely let you do that.
posted by wenestvedt at 7:02 AM on February 25, 2022 [1 favorite]

The options above sound good. If you're up for very minor electronics tinkering and copy-and-pasting a bit of code, another option would be to get some of the cheapest wifi-equipped Arduino Feathers and I2C thermometer boards. It's probably ~USD25/each total if you buy them one at a time, less in bulk.
posted by eotvos at 7:34 AM on February 25, 2022

I did something like this with an ESP32. It's a very small microcontroller with Bluetooth and WiFi capability. I used DS18B20 temperature sensors, and each ESP32 can control up to 8 separate sensors easily (you can probably do more if you need to, or just place multiple ESP32 data-collection points).

I started with self-written code to read the temperatures and report them to a web browser, but then discovered the Tasmota Home Automation project, which has an easier and more-comprehensive base package.

My sensor gadgets sit around wherever (one is inside a refrigerator, another is checking a radiant floor) and my main computer queries the temperature every 5 minutes and stores it in a JSONL file.

The final piece is a web page that retrieves the temperatures and produces graphs: 1 2 3
posted by spacewrench at 7:56 AM on February 25, 2022 [2 favorites]

I have the Ambient Weather WS-3000 system in my home for similar monitoring and display. I've had it for a year and been pleased with it. Haven't done any data analysis with it but it's possible. Website shows sold out but I've seen it on other retailer sites.
posted by paradeofblimps at 7:58 AM on February 25, 2022 [1 favorite]

Nth the Govee sensors that wenestvedt has. You're supposed to be able to export the data in CSV format (though I haven't yet tried it).
posted by odin53 at 8:19 AM on February 25, 2022 [1 favorite]

We use these Wireless Tag sensors and can recommend. Their version that tracks humidity in addition to temp is temporarily out of stock, though. Whatever sensors you pick, you'll also need this tiny little server thingy, which is currently on sale.
posted by 10ch at 8:38 AM on February 25, 2022

I use Netatmo for this.
posted by Hey, Zeus! at 10:50 AM on February 25, 2022

The Govee sensors I use take two AA batteries. I use Amazon Basics rechargeables, and I believe that they last for a couple of months.
posted by wenestvedt at 1:21 PM on February 25, 2022

We monitor temperature and humidity around the house with AcuRite sensors that transmit in the 433 MHz band. A Raspberry Pi receives the signals using an RTL-SDR dongle and RTL_433, dumps the data into influxdb, and runs a grafana dashboard for plots. The total cost to set this up with four wireless sensors was about $100. And the more expensive components (Pi and RTL-SDR device) have been generally useful for other projects.
posted by ContinuousWave at 4:56 PM on February 25, 2022 [1 favorite]

Response by poster: Thanks everybody, I really appreciate all the answers. (Feel free to keep them coming.)
posted by unus sum at 8:27 PM on February 25, 2022

I've been doing this with for the past 3-4 years with the Ambient Weather WS-2000, four extra temperature/humidity senors, and an outdoor PM2.5 sensor. The extra temperature sensors live in various parts of the house.

You can upload the data to ambientweather.net. The UX looks like this (that link is a random public weather station in Kansas, not mine). You don't have to make it public. And even if you make it public, I'm pretty sure it doesn't share indoor temperatures. But the indoor temperature/humidity readings look the same as the ones you see here.

You need some kind of base station to store and upload the data, even if you only want the indoor temperature sensors (e.g. the WS-2000). I'm not sure if there's a base station that doesn't also come with outdoor weather sensors.

Once uploaded, ambientweather.net has a public REST API you can use to export the data periodically for backup and the kind of analysis/visualization you can't do using their UX. It's just REST, so if you know what you're doing you should be fine, but fwiw ambient-archiver (which I wrote) is a CLI that handles all the API calls for you and allows you to maintain a local/cloud copy of the data. If for some reason you don't want to upload the data then I believe you can export from the base station using a smartcard.

The general UX of the Ambient Weather ecosystem (from the devices to the dashboard to the API) is enthusiast-level (i.e. a little rough around the edges), and you can tell the company's background is in weather sensing, not home automation or web services, but it's generally been fine!

If you'd like to see the data the API provides then memail me and I'll send over the last week or so :-)
posted by caek at 8:41 PM on February 26, 2022 [1 favorite]

In addition to the Govees, I have an Ambient Weather station, too, and its web interface is pretty sweet!
posted by wenestvedt at 6:10 AM on February 27, 2022