DIY Coffee Roaster uses Cordless Drills and a Camp Stove

We’re no stranger to coffee roasting hacks, but it’s been a while since we’ve seen a new DIY roaster design. Thankfully [Larry] has been hacking together a small-batch roaster with a bunch of off-the-shelf parts. He was originally trying to make a fully-automated roasting system, but after a bunch of failed prototypes, he settled on a simple roaster design that works great.

[Larry]’s roaster is designed for small batches of coffee (about 3oz). He has a small hopper with a motorized auger (cannibalized from a chocolate fountain) which drops coffee down into his roasting basket. The basket is mounted to a cordless screwdriver which rotates it to agitate the beans inside. A small camp stove provides the heat, which is placed right under the basket. The beans churn around in the roasting basket and heat up until they reach the desired roast level (typically between first and second crack).

Once the roasting is complete, another hand drill rotates the basket assembly to dump out the coffee. [Larry]’s build includes an assortment of knobs and switches which control the auger, basket speed, bean dumping, and even a “speedometer” gauge that shows how fast the basket is rotating. Want to build your own roaster? Check out the instructions for building [Larry]’s roaster or some other builds we’ve featured before.

Super Simple Cat Feeder

Sometimes, along comes a hack that is just that. A kludged collection of parts thrown together quickly to solve some problem. [mightysinetheta]’s Upcycled Cat Feeder is just that – no pretensions.

It’s a cat feeder built out of a drill, wall switch and mechanical clock timer for under $10. Pretty much the simplest electric cat feeder you can make. Survives power outages just fine, is single serving, but due to the noise and motion it makes, it is a perfect Pavlovian trainer for the cat. The best way to describe it is as a Rube Goldberg machine.

Set the timer for the planned feed time (up to 12 hours in advance). At the appointed time, the timer triggers, the drill rotates, the old, broken screwdriver chucked in the drill turns. The cord tied to the screwdriver winds up like a winch. This pulls up the lid covering the cat’s dinner plate. The noisy drill announces it’s dinner time. When fully raised, the lid pushes up a short piece of PCV pipe. This flips a switch, that shuts off the drill. If you need build instructions, fear not. [mightysinetheta] has detailed build instructions although the pictures are probably all you’ll need.

Check the video after the break.

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DIY AC for the Hot Shop

Working out in the shop is usually super fun but if it’s summertime, watch out, it can get hot! We’ve all been there and we’ve all wished we could do something about it. Well, woodworker and general DIYer [April] has stepped up to the plate and built a portable low-buck AC unit to cool her shop down to an acceptable temperature.

The unit is very simple and starts off with an old thrift store cooler. A hole is cut in the back of the cooler to make room for a fan that is directed to blow air inside the cooler and across blocks of ice. The air cools down as it passes over the ice and leaves out the top of the cooler through five 90-degree PVC elbows. After all the inlets and outlets were caulked, the entire unit was given a monochromatic black paint job.

[April] says you can feel the cool air blowing from about 5 feet away from the unit. She has measured the output air temperature to be 58-62ºF. If using loose ice cubes, the unit will work for 2-3 hours. Freezing milk jugs full of water gets about 5 hours of use.

RoomMote, a DIY Remote for Your Room Project

[Rohit] wrote in to tell us about a project he has created. Like most projects, his solves a problem. Sometimes while sleeping, a mosquito will infiltrate his room. He has a mosquito repellent machine but there are 2 problems, he has to get up to turn it on/off and it smells bad when in use. [Rohit] only needed a remote-controlled mosquito repelling machine but decided to make a 6 channel system he calls the RoomMote.

From the beginning, the plan was to use an old Sony TV remote to do the transmitting. The receiver unit was completely made from scratch. [Rohit] designed his own circuit around a surface mount MSP430 chip and made a really nice looking PCB to fit inside a project box he had kicking around. The MSP430 chip was programmed to turn relays on and off based on the signals received from the Sony remote.  These relays are inside an electrical box and control AC outlets. Just plug in your light, radio or mosquito repellent into the appropriate outlet for wireless control. Code for the MSP430 is made available on [Rohit’s] project page for anyone wanting to make something similar.

In addition to the relays, there is an RGB LED strip attached to the custom circuit board. By using more of the Sony remote’s buttons, the LED strip can output 6 pre-programmed colors, some mood lighting for the mosquitoes!

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Use A Lamp To See Into The Future

We’ve heard of magic lamps before, but this one is actually real. [Alex] has created a wall-mounted lamp that can tell you what the future will be like; at least as far as the weather is concerned. It is appropriately named “Project Aladdin” and allows you to tell a great deal about the weather at a glance as you walk out of the door.

The lamp consists of twelve LED strips arranged vertically. The bottom strip represents the current hour, and each strip above represents another hour in the future. The color of each strip indicates the temperature, and various animations of the LEDs within each strip indicate wind speed and precipitation.

The system uses a weather forecasting backend built-in Java, which is available on the project’s page. The LEDs are controlled by an application that is written in C, and the entire set of LEDs are enclosed in a translucent housing which gives it a very professional appearance. Be sure to check out the demo video after the break. Be sure to check out some other takes on weather lamps which use regular desk lamps instead of intricate scratch-made LED lamps.

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Indicator for Forgetful-Minded Garage Door Users

[Gareth] had a friend who regularly forgot to close his garage door after parking his car and heading inside. Since [Gareth] was familiar with basic electronics and an overall good pal, he offered to make a device that would indicate whether the garage door was open or not.

The project starts off simple with an Arduino and ultrasonic distance sensor. Both are mounted to the ceiling of the garage with the ultrasonic sensor pointed down. When the garage door is open, the sensor outputs a shorter distance measurement than when the garage door is closed.

Now that the system knows when the door is open or closed, the next part was sending a signal inside the house. He could have run a wire up through the house walls to an LED indicator but decided to go wireless with a 433mhz transmitter. There is a second Arduino inside equipped with a 433mhz receiver. When the garage door is open, the Arduino inside the house flashes an LED reminding the forgetful occupant to close the door.

[Gareth] made all his code for both the sensor/transmitter and the receiver available on his site for anyone interested in making something similar.

Chili-Gation With The MSP430

[Dave] used to grow chili peppers, but after moving to Texas he noticed his plants were drying up and dying off. This is understandable; Texas is freaking hot compared to his old home in the UK. These chilis needed a watering system, and with a pump, relay module, and an MSP430 launchpad, it was pretty easy to put together.

The core of the build is an MSP430 launchpad, a Sharp Memory LCD BoosterPack for the user interface, and a few bits and bobs for pumping water from a large soda bottle to the plant.

Before beginning his build, [Dave] took a look at commercial watering systems, but could only find huge irrigation systems for greenhouses or gardens. This was obviously overkill, but with a few parts – a six volt pump and a relay control board – [Dave] was able to make a simple system that keeps chilis watered for seven days between refilling the reservoir.