Replacement refrigerator controller

[Michael] got his hands on a refrigerator that he intended to store beer in but found that it ran constantly. Instead of buying a new thermostat he and his friend [Doug] set out to build an Arduino-based controller for the fridge.

The finished project will switch 240v so they’ve used a transformer to power the logic circuitry and a solid state relay to handle the load switching, with a Dallas 1820 for temperature data. Because the Arduino offers more capabilities than the average thermostat hack they also decided to tap into its potential by adding an Ethernet shield. We see the Arduino as a prototyping device and so do these folks. Once the bugs in their first PCB prototype are worked out the circuit will use the ATmega328 and do away with the Arduino.

[via @littlebirdceo]

X-mas Hack: 8-channel musical show

We’ve been seeing them appear one house at a time over the last few weeks as Christmas lights are making their annual appearance. Some folks just throw a set of net-style lights on the bushes and call it good but that wouldn’t suit [Noel]. He’s outfitted his house with a show that includes music, 8 controllable light channels, and an Internet interface.

He’s used a plastic toolbox as an enclosure to house everything. Affixed to the base of the enclosure are eight solid state relays for the strings of lights. An Arduino is used to control the SSR switching, playback music through an FM transmitter, and to interface with the wireless bridge.

Rubberneckers can tune their radio to the broadcast frequency and log into the web interface to request their favorite tune or track Santa’s current location. The device even implements VU monitoring to sync the light show with the music. If you want more, watch the video after the break or check out his step-by-step instructions. The Arduino library sure makes the code pulling this all together pretty simple!

[Read more...]

Grow box controls heater, fans, and water

grow_box_controller

The Cheap Vegetable Gardner wanted more automation than their previous PS2 controller based grow system. This time they set out to design a full featured, compact grow controller that can measure temperature and humidity as well as control a heat lamp, fan, and water pump. An Arduino provides USB connectivity and interfaces the solid state relays and sensors. The assembled project all fits in a box but we are left wondering how much heat the four SSRs generate and will it be a problem?

[Thanks shawn]

Beer brewer’s temperature controller

freezer_temperature_controller

Steady fermentation temperatures, usually at about 65 degrees Fahrenheit, are an important part of brewing beer. Because of this, the wort (unfermented beer) is often temperature controlled during fermentation. [android] needed a temperature controller for fermenting beer in a chest freezer. Much like the energy efficient fridge hack from last month, the chest freezer is switched on and off to achieve the desired temperature. Instead of buying a controller, [android] built around an existing design. His project uses a solid state relay to switch an outlet on and off.

The temperature is controlled by a home thermostat. He removed the thermistor from the unit and extended it with 24 gauge wire so that it can go inside of the chest freezer. Utilizing a junction box, the freezer is plugged into one switched outlet and controlled by the thermostat via the relay. The other outlet is unswitched and provides DC power for the relay using a wall wort transformer. Although this thermostat cannot be set cold enough for lagering, it is perfect for keeping kegs at the correct beer serving temperatures when not being used for fermentation.

How to build a life-sized electronic game

life_size_light_games

We’re very impressed with [Steve's] Electronic Snowball Fight game. It consists of two life-sized players standing opposite of each other. Each can throw a snowball or duck, the object is to hit the other person and not get hit yourself. He’s utilized a lot of good building techniques that could be easily adapted to other types of game play. [Read more...]

Giant bulb VU meter

bulb

The latest Inventgeek project is a 12 outlet control box. They decided to demo it using a giant bulb based VU meter. The control box has 12 individual outlets hooked up to two layers of six solid state relays. [Jared] notes that SSRs can be very expensive, but he purchased his on eBay for ~$10 each. Wiring and installation on this project is incredibly clean and they plan on using the control box for future how-tos. The simple audio circuit used for the VU is based on the LM3915. You’ll find full plans on the site or you can watch the overview video embedded below.

[Read more...]

PID SMD reflow hot plate

pid_hotplate

[mightyohm] put together a nice piece of lab kit. It’s a PID controlled hot plate. The plate is capable of reaching 500F, hot enough to do SMD reflow soldering. The large chunk of metal has a hole drilled through the center to contain a cartridge heater. A thermocouple is used to monitor the temperature of the plate. Ceramic standoffs separate the plate from the rest of the device, but he still needs to come up with a way to stop the radiant heating. The control box houses the surplus PID controller along with the power switch and solid state relay (SSR).