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Fixing (And Improving!) An Annoying Apartment Entry System

December 11, 2022 by 7 Comments

[Zak]’s two-floor apartment has a typical door entry control system, but the setup is less than ideally convenient. The wall-mounted telephone-like intercom is downstairs, but [Zak] is usually upstairs. What’s an enterprising hacker to do? Obviously the most elegant solution is to simply do without visitors in the first place, but [Zak] opted for a more full-featured solution to the problem.

The layout of the typical wall-mounted door intercom is less than ideal.

He fixed things with a custom ESP8285-based board that, with the help of opto-isolation, allows him to detect visitors and grant entry without having to be physically present at the wall-mounted intercom. It’s even integrated into Telegram, and has a few neat new features. Let’s take a look.

The first interesting bit is how [Zak] rolled his own opto-isolation. The door entry system uses 14 VAC and is frankly — electromagnetically-speaking — a very noisy device. Attaching GPIO pins directly to this system from the ESP board for interfacing is not an option. The solution in situations like this is to use opto-isolation, so that interfaced devices can be electrically isolated from one another.

Rather than use off-the-shelf options, [Zak] opted to keep things small and economical by rolling his own solution using side-mounted IR LEDs on the small interface PCB. LEDs can also act as photodiodes, so by pointing two LEDs directly at one another and driving one LED from the door control system and measuring the small amount of resulting current on the other LED, [Zak] can detect states without having to directly connect a GPIO pin.

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Keeping An Eye On Heating Oil

November 2, 2022 by 70 Comments

Energy costs around the world are going up, whether it’s electricity, natural gas, or gasoline. This is leading to a lot of people looking for ways to decrease their energy use, especially heading into winter in the Northern Hemisphere. As the saying goes, you can’t manage what you can’t measure, so [Steve] has built this system around monitoring the fuel oil level for his home’s furnace.

Fuel oil is an antiquated way of heating, but it’s fairly common in certain parts of the world and involves a large storage tank typically in a home’s basement. Since the technology is so dated, it’s not straightforward to interact with these systems using anything modern. This fuel tank has a level gauge showing its current percentage full. A Raspberry Pi is set up nearby with a small camera module which monitors the gauge, and it runs OpenCV to determine the current fuel level and report its findings.

Since most fuel tanks are hidden in inconvenient locations, it makes checking in on the fuel level a breeze and helps avoid running out of fuel during cold snaps. [Steve] designed this project to be reproducible even if your fuel tank is different than his. You have other options beyond OpenCV as well; this fuel tank uses ultrasonic sensors to measure the fuel depth directly.

Automate Your Desk With The Upsy Desky

August 28, 2022 by 33 Comments

It might be surprising for some, but humans actually evolved to be long-distance runners. We aren’t very fast comparatively, but no other animal can run for as long or as far as a human can. Sitting at a desk, on the other hand, is definitely not something that we’re adapted to do, so it’s important to take some measures to avoid many of the problems that arise for those that sit at a desk or computer most of the day. This build takes it to the extreme, not only implementing a standing desk but also a ton of automation for that desk as well.

This project is an improvement on a prior build by [TJ Horner] called the WiFi Standing Desk Controller. This new version has a catchier name, and uses an ESP32 to run the show. The enclosure is 3D printed and the control board includes USB-C and a hardware UART to interface with the controller. The real perks of this device are the automation, though. The desk can automatically lift if the user has been sitting too long, and could also automatically lift if it detects no one is home (to help keep a cat off of the desk, for example). It also includes presets for different users, and can export data to other software to help analyze sitting and standing patterns.

The controller design is open source and could be adapted to work on a wide-array of powered desks. As we’ve seen in the past, with the addition of a motor, even hand-crank standing desks can be upgraded. If you haven’t gotten into the standing desk trend yet, we hope that you are at least occasionally going for a run.

Voice-Controlled Smart Home From The Foundation Up

August 16, 2021 by 20 Comments

Smart homes are becoming an increasingly popular way to automate one’s home, whether it’s turning on lights, closing blinds, or even feeding pets. But the commercial offerings often rely on an internet connection to reach servers in order to work, which invites a lot of privacy concerns for a large percentage of us as well as being inconvenient when the internet is down. Essentially the only way to have a privacy-respecting, self-sufficient smart home is to build one on your own from the ground up, which is exactly what [Xasin] has done with this project.

This build is based on ESP32 modules with a Raspberry Pi as a hub, but it’s not as simple as a MQTT implementation. Not only does the self-contained home automation setup not rely on any outside services, but a failure of the central Pi server will not impact the nodes either as they are configured to continue operating independently even without central control. This allows for a robust home automation implementation without a single point of failure, and also includes some other features that are helpful as well including voice control, all while retaining a core design philosophy that makes it relatively easy to build.

Not only is the build technologically impressive for its standalone capabilities and its elimination of privacy concerns, but [Xasin] also did an excellent job with the physical design as well, adding plenty of RGB and a hexagonal enclosure that gives it a unique look wherever its is placed. If you’re renting right now or otherwise unable to interface any automation with your current home, be sure to take a look at some projects that do home automation without making any permanent changes.

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Heating A Home With Sunlight… And Water

April 22, 2021 by 64 Comments

The sun is a tremendous source of energy, and while photovoltaic panels are an easy way to harvest some of that energy especially now that prices for them are incredibly low, there are plenty of other ways to tap into that free energy as well. [Engelbert] was looking for alternative ways to heat his house since traditional methods were prohibitively expensive, and ended up building a heat exchanger using solar-heated water to cover his home heating needs. (Google Translate from Dutch)

The system uses several large roof-mounted hot water heating panels. The heat captured by them is then pumped into an underground pipe network which is able to warm up a large area of earth in the summer. In the winter, that heat is able to be extracted back out of the earth and used to heat his home. The system includes almost three kilometers of pipe which are buried two meters below grade, so this will probably not be a weekend project, but it still cost much less than the €80,000 to install gas heating in his home.

[Engelbert] is able to use this self-built system to keep his home and another smaller building at a constant 23°C all year. He actually overbuilt the system slightly and has since disconnected almost half of the pipes, but we certainly understand the desire to over-engineer things around here. The only problem he has had is with various government entities that are slow to adopt energy-efficient systems like these. Perhaps the Dutch government can take some notes from the Swiss when it comes to installing geothermal systems like these.

Thanks to [Jero] for the tip!

The Ground Beneath Your Feet: SuperAdobe Construction

October 27, 2020 by 25 Comments

Homes in different parts of the world used to look different from each other out of necessity, built to optimize for the challenges and benefits of local climate. When residential climate control systems became commonplace that changed. Where a home in tropical south Florida once required very different building methods (and materials) compared to a home in the cold mountains of New England, essentially identical construction methods are now used for single-family homes in any climate. The result is inefficient and virtually indistinguishable housing from coast to coast, regardless of climate. As regions throughout the world are facing increasingly dire housing shortages, the race is on to find solutions that are economical and available to us right now.

The mission of CalEarth, one of the non-profits that Hackaday has teamed up with for this year’s Hackaday Prize, is to address that housing shortage by building energy-efficient homes out of materials already available in the areas that they will be built. CalEarth specializes in building adobe, or earth, homes that have a large thermal mass and an inexpensive bill of materials. Not only does this save on heating and cooling costs, but transportation costs for materials can be reduced as well. Some downside to this method of construction are increased labor costs and the necessity of geometric precision of the construction method, both of which are tackled in this two-month design challenge.

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Home Monitoring, Without All The Sensors

July 17, 2020 by 15 Comments

Smart homes come with a lot of perks, not least among which is the ability to monitor the goings-on in your home, track them, and make trends. Each piece of monitoring equipment, such as sensors or cameras, is another set of wires that needs to be run and another “thing” that needs to be maintained on your system. There are sometimes clever ways of avoiding sensors, though, while still retaining the usefulness of having them.

In this build, [squix] uses existing sensors for electricity metering that he already had in order to alert him when his oven is pre-heated. The sensor is a Shelly 3EM, and the way that it interfaces with his home automation is by realizing that his electric oven will stop delivering electricity to the heating elements once it has reached the desired temperature. He is able to monitor the sudden dramatic decrease in electricity demand at his house with the home controller, and use that decrease to alert him to the fact that his oven is ready without having to install something extra like a temperature sensor.

While this particular sensor may only be available in some parts of Europe, we presume the idea would hold out across many different sensors and even other devices. Even a small machine learning device should be able to tell what loads are coming on at what times, and then be programmed to perform functions based on that data.

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