PID Controlled Charcoal BBQ – Put an Arduino on it!

At Maker Faire Milwaukee this past weekend, [basement tech]  was showing off his latest build, a PID controlled charcoal grill. While it hasn’t QUITE been tested yet with real food, it does work in theory.

PID (a feedback loop with some fancy math used to adjust the input to get a consistent output) controlled cooking is commonly used for sous vide, where one heats up a water bath to a controlled temperature to cook food in plastic bags. Maintaining water temperature is fairly easy. Controlling a charcoal barbecue is much more difficult. [basement tech] accomplishes this with controlled venting and fans. With the charcoal hot and the lid on, there are two ways to control temperature; venting to let hot air out, and blowing air on the coals to make them hotter. A thermocouple sensor stuck through the grill gives the reading of the air inside, and an Arduino nearby reads that and adjusts the vents and fans accordingly.

The video goes into extensive detail on the project, and describes some of the challenges he had along the way, such as preventing the electronics and servos from melting.

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Brasilia Espresso Machine PID Upgrade Brews Prefect Cup of Energy

Coffee, making and hacking addictions are just bound to get out of control. So did [Rhys Goodwin’s] coffee maker hack. What started as a little restoration project of a second-hand coffee machine resulted in a complete upgrade to state of the art coffee brewing technology.

coffee_hack_arduinoThe Brasilia Lady comes with a 300 ml brass boiler, a pump and four buttons for power, coffee, hot water and steam. A 3-way AC solenoid valve, wired directly to the buttons, selects one of the three functions, while a temperamental bimetal switch keeps the boiler roughly between almost there and way too hot.

To reduce the temperature swing, [Rhys] decided to add a PID control loop, and on the way, an OLED display, too. He designed a little shield for the Arduino Nano, that interfaces with the present hardware through solid state relays. Two thermocouples measure the temperature of the boiler and group head while a thermal cut-off fuse protects the machine from overheating in case of a malfunction.

Also, the Lady’s makeup received a complete overhaul, starting with a fresh powder coating. A sealed enclosure along with a polished top panel for the OLED display were machined from aluminum. [Rhys] also added an external water tank that is connected to the machine through shiny, custom lathed tube fittings. Before the water enters the boiler, it passes through a custom preheater, to avoid cold water from entering the boiler directly. Not only does the result look fantastic, it also offers a lot more control over the temperature and the amount of water extracted, resulting in a perfect brew every time. Enjoy [Rhys’s] video where he explains his build:

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Cozy Heat Control with an Arduino

[George Dewar] and his wife live in a typical 1940’s house in New Zealand , which in case you didn’t know, have a little insulation in the ceiling… and nowhere else. Like most, they put up with the cold — but after having a baby, [George] decided it was time to start controlling the heat a bit better.

They have an electric oil radiator which works well, but isn’t very smart. It only has 6 settings — not very useful when you’re trying to stay at a certain temperature. First off, they looked into a plug-in thermostat controller, and found a cheap one called the HeaterMate. Unfortunately it left a lot to be desired. For example, it didn’t seem to have PID control at all — and for an oil radiator, when you turn it off… it’s still going to heat the room for a while. He also found that because of the high current load of a heater … the device would read a few degrees over room temperature when operating. Unperturbed, [George] took this opportunity to design and build his own PID thermostat controller instead.  Continue reading “Cozy Heat Control with an Arduino”