Fail of the Week – Steam Cleaner fix goes bad

[Sven337] was gifted a steam cleaner, and seemed pretty happy because it helped clean the floor better than a regular mop. Until it fell one day, and promptly stopped working. It would produce steam for a short while and then start spitting out cold water, flooding the floor.

Like any self-respecting hacker, he rolled up his sleeves and set about trying to fix it. The most-likely suspect looked like the thermostat — it would switch off and then wouldn’t switch on again until the water temperature fell way below the target, letting out liquid water instead of steam after the first switching cycle. A replacement thermostat was ordered out via eBay.

Meanwhile, he decided to try out his hypothesis by shorting out the thermostat contacts. That’s when things went south. The heater worked, and got over-heated due to the missing thermostat. The over-temperature fuse in the heater coil blew, so [Sven337] avoided burning down his house. But now, he had to replace the fuse as well as the thermostat.

[Sven337] bundled up all the parts and put them in cold storage. The thermostat arrived after almost 2 months. When it was time to put it all together, a piece of fibreglass tubing that slides over the heater coil was missing. Without the protective sleeve, the heater coil was shorting out with the grounded heater body, blowing out the fuses in his apartment.

That’s when [Sven337] called it a day and threw out the darn steam mop — a few dollars down the drain, a few hours lost, but at least he learnt a few things. Murphy’s Law being what it is, he found the missing insulation sleeve right after he’d thrown it away.

Controlling Central Heating Via Wi-Fi

If you’ve ever lived in a building with manually controlled central heating, you’ll probably understand [Martin]’s motivation for this hack. These heating systems often have old fashioned valves to control the radiator. No Nest support, no thermostat, just a knob you turn.

To solve this problem, [Martin] built a Wi-Fi enabled thermostat. This impressive build brings together a custom PCB based on the ESP8266 Wi-Fi microcontroller and a mobile-friendly web UI based on the Open Thermostat Scheduler. The project’s web server is fully self-contained on the ESP8266.

To replace that manual value, [Martin] used a thermoelectric actuator from a Swiss company called HERZ. This is driven by a relay, which is controlled by the ESP8266 microcontroller. Based on the schedule and the measured temperature, the actuator lets fluid flow through the radiator and heat the room.

As a bonus, the device supports NTP for getting the time, MQTT for publishing real-time data, and ThingSpeak for logging and graphing historic data. The source code and design files are available under a Creative Commons license.

Arduino Thermostat Includes Vacation Mode

When [William’s] thermostat died, he wanted an upgrade. He found a few off-the-shelf Internet enabled thermostats, but they were all very expensive. He knew he could build his own for a fraction of the cost.

The primary unit synchronizes it’s time using NTP. This automatically keeps things up to date and in sync with daylight savings time. There is also a backup real-time clock chip in case the Internet connection is lost. The unit can be controlled via the physical control panel, or via a web interface. The system includes a nifty “vacation mode” that will set the temperature to a cool 60 degrees Fahrenheit while you are away. It will then automatically adjust the temperature to something more comfortable before you return home.

[William’s] home is split into three heat zones. Each zone has its own control panel including an LCD display and simple controls. The zones can be individually configured from either their own control panel or from the central panel. The panels include a DHT22 temperature and humidity sensor, an LCD display, a keypad, and support electronics. This project was clearly well thought out, and includes a host of other small features to make it easy to use.

Raspberry PiPhone Thermostat Monitors Your Entire House — Or At Least That’s The Plan

[Jeff McGehee] or how he likes to be known, [The Nooganeer] just finished his first big tech project after finishing grad school. It’s a connected thermostat that makes use of his old iPhone 4, and a Raspberry Pi.

Ever since [The Nooganeer] bought his first home with his wife back in the spring of 2014, he’s had ever consuming dream of adding home automation to every appliance. As he puts it…

Home automation has always been a fascination of mine.  How much time and irritation would I save if I didn’t have to worry about turning things on and off, or wonder in which state they were left?  How much more efficient would my home be?  Wouldn’t it be cool to always know the state of every power consumer in my home, and then be able to record and analyze that data as well?

His first challenge was making a smart thermostat — after all, heating and cooling your house typically takes the most energy. Having used a Raspberry Pi before he figured it would be the best brain for his system. After researching a bit about HVAC wiring, [The Nooganeer] settled on a Makeatronics Solid State Relay board to control the HVAC. This allows him to use the GPIO’s on the Raspberry Pi in order to control the furnace and AC unit.  Continue reading “Raspberry PiPhone Thermostat Monitors Your Entire House — Or At Least That’s The Plan”

Chinese Temperature/Humidity Sensor is Easily Hacked

There’s a new piece of electronics from China on the market now: the USR-HTW Wireless Temperature and Humidity Sensor. The device connects over Wi-Fi and serves up a webpage where the user can view various climate statistics. [Tristan] obtained one of these devices and cracked open the data stream, revealing that this sensor is easily manipulated to do his bidding.

Once the device is connected, it sends an 11-byte data stream a few times a minute on port 8899 which can be easily intercepted. [Tristan] likes the device due to the relative ease at which he could decode information, and his project log is very detailed about how he went about doing this. He notes that the antenna could easily be replaced as well, just in case the device needs increased range.

There are many great reasons a device like this would be useful, such as using it as a remote sensor (or in an array of sensors) for a homemade thermostat, or a greenhouse, or in any number of other applications. The sky’s the limit!

Custom Raspberry Pi Thermostat Controller

Thermostats can be a pain. They often only look at one sensor in a multi-room home and then set the temperature based on that. The result is one room that’s comfortable and other rooms that are not. Plus, you generally have to get up off the couch to change the temperature. In this day and age, who wants to do that? You could buy an off-the-shelf solution, but sometimes hacking up your own custom hardware is just so much more fun.

[redditseph] did exactly that by modifying his home thermostat to be controlled by a Raspberry Pi. The temperature is controlled by a simple web interface that runs on the Pi. This way, [redditseph] can change the temperature from any room in his home using a computer or smart phone. He also built multi-sensor functionality into his design. This means that the Pi can take readings from multiple rooms in the home and use this data to make more intelligent decisions about how to change the temperature.

The Pi needed a way to actually talk to the thermostat. [redditseph] made this work with a relay module. The Pi flips one side of the relays, which then in turn switches the buttons that came built into the thermostat. The Pi is basically just emulating a human pressing buttons. His thermostat had terminal blocks inside, so [redditseph] didn’t have to risk damaging it by soldering anything to it. The end result is a functional design that has a sort of cyberpunk look to it.

[via Reddit]

Wax Motors Add Motion to Your Projects

[electronicsNmore] has uploaded a great teardown and tutorial video (YouTube link) about wax motors. Electric wax motors aren’t common in hobby electronics, but they are common in the appliance industry, which means the motors can be often be obtained cheaply or for free from discarded appliances. Non-electric wax motors have been used as automotive coolant thermostats for years.  Who knows, this may be just what the doctor ordered for your next project.

As [electronicsNmore] explains, wax motors are rather simple devices. A small block of wax is sealed in a metal container with a movable piston. When heated, the wax expands and pushes the piston out. Once the wax cools, a spring helps to pull the piston back in.

The real trick is creating a motor which will heat up without cooking itself. This is done with a Positive Temperature Coefficient (PTC) thermistor. As the name implies, a PTC thermistor’s resistance increases as it heats up. This is the exact opposite of the Negative Temperature Coefficient (NTC) thermistors we often use as temperature sensors. PTC’s are often found in places like power supplies to limit in rush current, or small heating systems, as we have in our wax motor.

As the PTC heats up, its resistance increases until it stops heating. At the same time, the wax is being warmed, which drives out the piston. As you might expect, wax motors aren’t exactly efficient devices. The motor in  [electronicsNmore’s] video runs on 120 volts AC. They do have some advantages over solenoid, though. Wax motors provide smooth, slow operation. Since they are resistive devices, they also don’t require flyback diodes, or create the RF noise that a solenoid would.

Continue reading “Wax Motors Add Motion to Your Projects”