Joule Thief Battery Charger

A "Joule Thief" is a simple voltage booster circuit. It can increase the voltage of power source by changing the constant low voltage signal into a series of rapid pulses at a higher voltage. You most commonly see this kind of circuit used to power LEDs with a "dead" battery. But there are many more potential applications for this kind of circuit.

In this project, I am going to show you how you can use a Joule Thief to charge batteries with low voltage power sources. Because the Joule Thief is able to boost the voltage of a signal, you are able to charge a battery with a power source whose output voltage is actually lower than the battery itself.

This lets you take advantage of low voltage power sources such as thermoelectric generators, small turbines and individual solar cells.

For step by step instructions on how to make this project, check out the Instructable:
http://www.instructables.com/id/Joule-Thief-Low-Voltage-Battery-Charger/

Audio Treasure Hunt

Everyone loves treasure hunts. Running around on a quest to find your present makes any gift better. So just for fun, I designed my own variation of the game. I combined an Arduino microcontroller with an Adafruit Wave Shield to make an audio treasure hunt box.

The treasure hunters are given a code. When they enter the code into the box, it will play a short audio clip that gives them a clue as to where they should go next. When they arrive at this location, they will find another code, which they will enter and get another clue. This continues until eventually they arrive at the final location and find their present.

For step by step instructions on how to make this project, check out the Instructable:
http://www.instructables.com/id/Audio-Treasure-Hunt/

Hot Wire Ice Cutter

Have you ever wanted to sculpt something out of ice? Well here is an easy way to do it that doesn't require a chainsaw. In this project, I am going to show you how to make a "hot wire ice cutter."

The design for this project is very similar to other types of hot wire cutters. Electricity is sent through a piece of Nichrome wire. This heats the wire above the melting temperature of the material that you are working with. The wire can then be used to "cut" the material by melting it along a narrow line.

Because ice sculptures are often larger and more difficult to handle, I designed my cutter to be handheld rather than stationary on a table. I based my design largely on the "Hot Wire Foam Cutter" by Instructables user FlyWoodKB. I made a few modifications to make it safer and easier to use with ice.

For step by step instructions on how to  build this project, check out the Instructable:
http://www.instructables.com/id/Hot-Wire-Ice-Cutter/

3D Printing Pen Tutorial

In this project, I am going to give you a basic introduction to 3D printing pens and how to use them.

For a detailed walkthrough, check out the Instructable:
http://www.instructables.com/id/3D-Printing-Pen-Tutorial/

Wearable Temperature Sensor and Alarm

When working in extreme temperatures it is important to monitor your body temperature. In freezing weather, your fingers and toes get numb and you can develop frostbite without even noticing it. Likewise, if your core body temperature can drop too low and you can start to start to suffer the effects of hypothermia before you are aware of it.

So I designed an automatic temperature sensor that will monitor the temperature of your fingers, your toes, your torso as well as the outside temperature. This can help you to stay safe when working in extreme cold.

For step by step instructions on how to build this project, check out the Instructable:
http://www.instructables.com/id/Wearable-Temperature-Sensors-For-Working-in-Extrem/

Sound Activated Outet

The Clapper was a popular gadget in the 80's and 90's. It let you turn appliances on and off just by clapping. This can be pretty useful, but it has some limitations. First there is the problem of loud noises accidentally turning the lights off. Also, you can't control multiple outlets independently of each other.

So I decided to make programmable version of the Clapper using an Arduino microcontroller. The Arduino lets you set codes for each outlet. This eliminates false triggering and lets you control multiple outlets independently. Your lamp could be turned on and off with one clapping pattern and your fan could be controlled with another pattern.

The Arduino also lets you program how the outlets are turned on and off. For instance, if your internet router needs to be reset, you could program it to turn your internet router off for ten seconds and then turn it back on automatically. Or you could turn a heater on for a few minutes and automatically turn itself off.

For step by step instructions on how to build this project, check out the Instructable:

http://www.instructables.com/id/Sound-Activated-Outlet/

The Useless Candle (A Candle That Blows Itself Out)

A while back, I saw "The Most Useless Machine" by Instructables user Frivolous Engineering. This is a machine whose only function is to turn itself off. When you flip the power switch to turn it on, an arm pops out of the box and turns the power switch back off.

I love the hilarious absurdity of this project. So I decided to make some "useless" devices of my own. In this project, I am going to share with you how to make a "Useless Candle." Whenever you light this candle, it automatically blows itself out.

This is done with a simple light sensor and a small air pump. When the sensor detects the increased light from the candle being lit, it turns on an air pump. The air pump pushes air through a tube that is mounted to the candle holder and blows the candle out.

For step by step instructions on how build this project, check out the Instructable:
http://www.instructables.com/id/The-Useless-Candle-A-Candle-That-Blows-Itself-Out/