This image created using GPT-4o on Poe using the prompt “picture of an upright freezer connected to a computer for temperature monitoring, together with a graph and an alarm siren. Suitable for a professional blog. Be humorous and use a vintage theme.”

Freezer Monitoring: Because Ice Cream Is A Dish Best Served Cold

July 21, 2025 by John Elliot V 23 Comments

[Scott Baker] wrote in to let us know about his freezer monitor.

After a regrettable incident where the ice cream melted because the freezer failed [Scott] decided that what was called for was a monitoring and alerting system. We enjoyed reading about this hack, and we’ll give you the details in just a tick, but before we do, we wanted to mention [Scott]’s justifications for why he decided to roll his own solution for this, rather than just using the bundled proprietary service from the white goods manufacturer.

We’re always looking for good excuses for rolling our own systems, and [Scott]’s list is comprehensive: no closed-source, no-api cloud service required, can log with high fidelity, unlimited data retention, correlation with other data possible, control over alerting criteria, choice of alerting channels. Sounds fair enough to us!

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Data Visualization And Aggregation: Time Series Databases, Grafana And More

June 30, 2025 by Maya Posch 12 Comments

If there’s one thing that characterizes the Information Age that we find ourselves in today, it is streams of data. However, without proper ways to aggregate and transform this data into information, it’ll either vanish into the ether or become binary blobs gathering virtual dust on a storage device somewhere. Dealing with these streams of data is thus essential, whether it’s in business (e.g. stock markets), IT (e.g. services status), weather forecasting, or simply keeping tracking of the climate and status of devices inside a domicile.

The first step of aggregating data seems simple, but rather than just writing it to a storage device until it runs out of space like a poorly managed system log, the goal here isn’t merely to record, but also to make it searchable. After all, for information transformation we need to be able to efficiently search and annotate this data, which requires keeping track of context and using data structures that lend themselves to this.

For such data aggregation and subsequent visualization of information on flashy dashboards that people like to flaunt, there are a few mainstream options, with among ‘smart home’ users options like InfluxDB and Grafana often popping up, but these are far from the only options, and depending on the environment there are much more relevant solutions.

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An Over-Engineered Basement Monitor

November 25, 2024 by Lewin Day 10 Comments

[Stephen] has a basement that depends on a sump pump. What that means is if the pump fails or the power goes out, the basement floods—which is rather undesirable. Not wanting to rely on a single point of failure, [Stephen] decided to build a monitor for the basement situation, which quickly spiralled to a greater degree of complexity than he initially expected.

The initial plan was just to have water level sensors reporting data over a modified CATS packet radio transmitter. On the other end, the plan was to capture the feed via a CATS receiver, pipe the data to the internet via FELINET, and then have the data displayed on a Grafana dashboard. Simple enough. From there, though, [Stephen] started musing on the possibilities. He thought about capturing humidity data to verify the dehumidifier was working. Plus, temperature would be handy to get early warning before any pipes were frozen in colder times. Achieving those aims would be easy enough with a BME280 sensor, though hacking it into the CATS rig was a little challenging.

The results are pretty neat, though. [Stephen] can now track all the vital signs of his basement remotely, with all the data displayed elegantly on a nice Grafana dashboard. If you’re looking to get started on a similar project, we’ve featured a great Grafana guide at a previous Supercon, just by the by. All in all, [Stephen’s] project may have a touch of the old overkill, but sometimes, the most rewarding projects are the ones you pour your heart and soul into!

A DIY DIN rail mounted rack of PLC components for home automation

2024 Home Sweet Home Automation: A DIY SCADA Smart Home

March 20, 2024 by Dave Rowntree 22 Comments

A SCADA-style display of icons and control buttons — Touch-screen control and monitoring

Supervisory control and data acquisition, or SCADA, systems sit in the background in industrial settings, performing all kinds of important jobs but in an ad-hoc setup, depending on the precise requirements of the installation. When we think about home automation systems, they’re pretty much the same deal: ad-hoc systems put together from off-the-shelf components and a few custom bits thrown in. [Stefan Schnitzer] clearly has significant knowledge of SCADA in an industrial setting and has carried this over into their home for their entry into the Hackaday 2024 Home Sweet Home Automation Contest. Continue reading “2024 Home Sweet Home Automation: A DIY SCADA Smart Home” →

Image of the presenter on the podium, in front of the projector screen with graphs shown on it

Supercon 2022: [Alex Whittemore] On Treating Your Sensor Data Well

September 15, 2023 by Arya Voronova 4 Comments

If you build your own devices or hack on devices that someone else has built, you know the feeling of opening a serial terminal and seeing a stream of sensor data coming from your device. However, looking at scrolling numbers gets old fast, and you will soon want to visualize them and store them – which is why experienced makers tend to have a few graph-drawing and data-collecting tools handy, ready to be plugged in and launched at a moment’s notice. Well, if you don’t yet have such a tool in your arsenal, listen to this 16-minute talk by [Alex Whittemore] to learn about a whole bunch of options you might not even know you had!

For a start, there’s the Arduino Serial Plotter that you get for free with your Arduino IDE install, but [Alex] also reminds us of the Mu editor’s serial plotter – about the same in terms of features, but indisputably an upgrade in terms of UX. It’s not the only plotter in town, either – Better Serial Plotter is a wonderful standalone option, with a few features that supercharge it, as [Alex] demonstrates! You don’t have to stop here, however – we can’t always be tethered to our devices’ debugging ports, after all. Continue reading “Supercon 2022: [Alex Whittemore] On Treating Your Sensor Data Well” →

Long-Range Thermocouple Sensor Sips Battery Power

July 20, 2022 by Lewin Day 4 Comments

Sometimes you need to know the temperature of something from a ways away. That might be a smoker, a barbecue, or even a rabbit hutch. This project from [Discreet Mayor] might just be what you’re looking for.

[Discreet Mayor] remotely keeps an eye on the meat, but doesn’t blab about it.

It consists of a MAX31855 thermocouple amplifier, designed for working with commonly-available K-type thermocouples. This is hooked up to a Texas Instruments CC1312 microcontroller, which sends the thermal measurements out over the 802.15.4 protocol, the same which underlies technologies like Zigbee and Thread. It’s able to send radio messages over long distances without using a lot of power, allowing the project to run off a CR2023 coin cell battery. Combined with firmware that sleeps the system when it’s not taking measurements, [Discreet Mayor] expects the project to run up to several years on a single battery.

The messages are picked up and logged in a Grafana setup, where they can readily be graphed. For extra utility, any temperatures outside a preset range will trigger a smartphone alert via IFTTT.

Keeping a close eye on temperatures is a key to making good food with a smoker, so this project should serve [Discreet Mayor] well. For anyone else looking to monitor temperatures remotely with a minimum of fuss, it should also do well!

More Software-Defined Radio Projects Using DragonOS

November 3, 2021 by Bryan Cockfield 14 Comments

DragonOS, a Debian-based Linux distribution specifically packaged for software-defined radio functionality, roared onto the wavelengths during the beginnings of the various pandemic lockdowns last year. Since then [Aaron], the creator of the OS, has been busy adding features to the distribution as well as creating plenty of videos which show off its capabilities and also function as how-tos for people who might want to learn about software-defined radio. The latest is a video about using this software to detect radio signals in certain specified spectrums.

This build uses two RTL-SDR devices paired with the DragonOS software suite to automatically detect active frequencies within a specified frequency range and that aslo exceed a threshold measured above the average noise floor. The video includes the setup of the software and its use in detecting these signals, but also includes setup of influxdb and Grafana which provide logging capabilities as well. Using this setup, multiple receivers either local or over the internet can then be configured to dump all the identified frequencies, powers, and time stamps into DragonOS.

[Aaron] has also been helping developers to build the SDR4space.lite application which includes GPS support, so he hopes that in a future video a user will be able to easily associate location to identified frequencies. Projects like these also serve as a reminder that getting into software-defined radio is as easy as buying a $10 USB radio receiver and configuring some free software to do anything that you can imagine like tracking ships and airplanes in real time.

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