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17 Articles

A Smart Power Distribution Unit For Home Automation

April 25, 2024 by 28 Comments

Power distribution units, as the name implies, are indispensable tools to have available in a server rack. They can handle a huge amount of power for demands of intensive computing and do it in a way that the wiring is managed fairly well. Plenty of off-the-shelf solutions have remote control or automation capabilities as well, but finding none that fit [fmarzocca]’s needs or price range, he ended up building his own essentially from scratch that powers his home automation system.

Because it is the power supply for a home automation system, each of the twelve outlets in this unit needed to be individually controllable. For that, three four-channel relay boards were used, each driven by an output on an ESP32. The ESP32 is running the Tasmota firmware to keep from having to reinvent the wheel, while MQTT was chosen as a protocol for controlling these outlets to allow for easy integration with the existing Node-RED-based home automation system. Not only is control built in to each channel, but the system can monitor the power consumption of each outlet individually as well. The entire system is housed in a custom-built sheet metal enclosure and painted to blend in well with any server rack.

Adding a system like this to a home automation system can simplify a lot of the design, and the scalable nature means that a system like this could easily be made much smaller or much larger without much additional effort. If you’d prefer to keep your hands away from mains voltage, though, we’ve seen similar builds based on USB power instead, with this one able to push around 2 kW.

Automating The Most Analog Of HVAC Equipment

February 20, 2023 by 35 Comments

Burning wood, while not a perfect heating solution, has a number of advantages over more modern heating appliances. It’s a renewable resource, doesn’t add carbon to the atmosphere over geologic time scales like fossil fuels do, can be harvested locally using simple tools, and it doesn’t require any modern infrastructure to support it. That being said, wood stoves aren’t something that are very high-tech and don’t lend themselves particularly well to automation as a result, at least with the exception of this wood stove from [jotulf45v2].

While this doesn’t automate the loading or direct control of a modern pellet stove, it does help [jotulf45v2] know when the best times are for loading more wood into the stove and helps keep the stove in the right temperature range to avoid the dangerous formation of creosote on the inside of his chimney caused by low temperature burns. Two temperature sensors, one on the stovetop and the other on the stove pipe, monitor the stove exhaust temperature. They feed data to a Node-RED system running on a Raspberry Pi which automatically notifies the user by text message when certain stove temperatures are reached.

For anyone heating with wood, tools like this are indispensable to help avoid spending an otherwise unnecessary amount of time getting a fire up to temperature quickly without over-firing the stove. Modern pellet stoves have some more modern conveniences like this built in, but many of the perks of using cord wood are lost with these devices. There are plenty of other ways to heat with wood too; take a look at this custom wood boiler which serves as a hot water heater.

Farm Data Relay System: Combine LoRa And 2.4 Ghz Networks Without WiFi Routers And Cloud Dependence

July 2, 2022 by 25 Comments

Setting up a wireless sensor network over a wide area can quickly become costly, and making everything communicate smoothly can be a massive headache, especially when you’re combining short range Wi-Fi with long range LoRa. To simplify this, [Timm Bogner] created Farm Data Relay System which simplifies the process of combining LoRa, 2.4Ghz modules and serial communications in various topologies over wide areas.

The FDRS uses a combination of ESP32/8266 sensor nodes for short range, and LoRa nodes for long range. The ESP nodes use Espressif’s connectionless ESP-NOW peer-to-peer protocol on which allow multiple ESP boards to communicate directly without the need for a Wi-Fi router. The ESP modules can have one of 3 roles, nodes, repeaters or gateways, and gateways and repeaters share the same code. Nodes take sensor inputs, and are configured to each have a unique READING_ID.

Relays just retransmit ESP-NOW packets to extend the network range, while gateways convert packets between ESP-NOW, MQTT over Wi-Fi, LoRa or serial messages as required. Repeaters and gateways each have a unique UNIT_MAC for addressing. The code that handles communication for the ESP devices is simple and well documented, so you only need to set a few configuration values, and then can focus your efforts on the code required for your specific application.

The hub of the system is a Raspberry Pi running Node-RED which acts as the final MQTT gateway and connects to the ESP MQTT gateways. This means that all the action happens in the local network, without being dependent on an internet connection and cloud service. However, it can still send and receive data over the internet using MQTT or any other protocol as required. Node-RED makes it particularly easy to build custom automations and interfaces.

In the video after the break, Andreas Spiess, the man with the Swiss accent, who also has a hand in the project, goes over all the features, setup and caveats.

Continue reading “Farm Data Relay System: Combine LoRa And 2.4 Ghz Networks Without WiFi Routers And Cloud Dependence” →

Remote MQTT Temperature Sensor Shows How It’s Done

March 13, 2022 by 7 Comments

First of all, there are definitely simpler ways to monitor remote temperatures, but [Mike]’s remote MQTT temperature sensor and display project is useful in a few ways. Not only does it lay out how to roll such a system from scratch, but it also showcases system features like solar power.

After all, if one simply wants to monitor temperature that’s easily done, but once one wishes to log those temperatures and use them to trigger other things, then rolling one’s own solution starts to get more attractive. That’s where using someone else’s project as a design reference can come in handy.

[Mike’s] solution uses two Wemos D1 boards: one with a DS18B20 temperature sensor for outdoors, and one with a small OLED screen for an interior display. The external sensor relies on a rechargeable 18650 cell and a solar panel for a hassle-free power supply, and the internal sensor (of which there can be many) has a cute enclosure and is powered by USB. On the back end, a Raspberry Pi running an MQTT gateway and Node Red takes care of the operational side of things. The whole system has been happily running for over two years.

What is MQTT? It is essentially a messaging protocol, and takes care of the whole business of reliably communicating data back and forth between IoT devices. It scales very well and doesn’t need to be hard or intimidating; our own [Elliot Williams] can tell you all about implementing it.

Scratch Built Tracked Robot Reporting For Duty

June 17, 2021 by 18 Comments

Inspired by battle-hardened military robots, [Engineering Juice] wanted to build his own remote controlled rover that could deliver live video from the front lines. But rather than use an off-the-shelf tracked robot chassis, he decided to design and 3D print the whole thing from scratch. While the final product might not be bullet proof, it certainly doesn’t seem to have any trouble traveling through sand and other rough terrain.

Certainly the most impressive aspect of this project is the roller chain track and suspension system, which consists of more than 200 individual printed parts, fasteners, bearings, and linkages. Initially, [Engineering Juice] came up with a less complex suspension system for the robot, but unfortunately it had a tendency to bind up during testing. However the new and improved design, which uses four articulated wheels on each side, provides an impressive balance between speed and off-road capability.