Home Power Monitoring

July 5, 2009 by Eliot 25 Comments

powermonitor

Reader [john] finished up his home power monitor over the holiday weekend. It uses a pair of current transducers clamped onto the mains. These output 0-3V and are read by the Arduino’s ADC. The Arduino averages samples over a 20 second period, calculates power used, and uploads it using an Ethernet Shield. The shield can’t do DNS lookups, so he uses a WRT54G to negotiate with the remote webserver. He admits that the system could be more accurate; it can’t detect small loads like wall warts. He also says that money could be saved by talking serial to the router instead of over ethernet. Here are the current usage charts.

You can find many power monitor projects like this in out Home Hacks category.

Capacitive Discharge Cutting

July 4, 2009 by Steve Watkins 25 Comments

capacitive discharge cutting

Capacitive discharge cutting provides more control than linear transformer versions. A very large capacitor is charged to a precise voltage and then discharged through the material to produce a controlled cut. The same device can also be used for spot and tab welding. A video of copper roof flashing being cut is embedded below. An example of a linear transformer can be found in our our How-to: build your own spot welder.

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Lego Modded Antenna Tuner

July 3, 2009 by Steve Watkins 15 Comments

legomoddedtunner

This antenna tuner is controlled remotely using geared motors and legos. The tuner needed to be closer to the antenna for performance reasons. This created a problem; most of the radio gear is inside while the tuner is outside. The gear motors and Legos combine to form a closed loop servo, operating two air core caps and an inductor switch. A control box placed near the radio is hard wired to the modded tuner outside. We would like to see something like this under gesture control using the Wii MotionPlus + Arduino.

Poor Man’s Thermographic Camera

July 1, 2009 by Steve Watkins 24 Comments

thermographic camera

Using an IR thermometer, there are two ways to go about building a thermographic camera. The first uses a pan and tilt head. Scan lines are emulated, as a computer controls panning from left to right, taking a temperature sample from each step. Vertical resolution is accomplished by tilting. Another method uses a web cam attached to the thermometer. The thermometer’s laser pointer is captured with temperature annotations, as the computer records the field of view. We think the best outcome can be found with a combination of both methods. The video embedded below demonstrates the results. This would be a good addition to the Autonomous paintball sentry.

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The Snow Clock

July 1, 2009 by Caleb Kraft 20 Comments

Snow days are great, but generally you still have to wake up to find out if it is a snow day. [insingertech] decided to make a system to solve this problem. He made an alarm clock that would automatically de activate if school is cancelled. What a pleasant surprise it would be to just wake up and find that you had been allowed to sleep in. It is using an Arduino and a python script to control the state of the alarm based off of an online school closing announcement. You can download the software from the instructable.

Custom Car Door Keypad

June 30, 2009 by Zach Banks 25 Comments

carkeypad

[Michael] has a keypad in his previous car’s door and he missed it enough to hack one into his Dodge Caliber. He bought a Ford keypad and mounted it inside his door with some custom electronics. He started with an Arduino nano to receive and authenticate button presses. This then splices into wires in the door that control the door lock. The program has a 5-digit code to unlock the door, but simply pressing 1 twice will lock the doors. He also implemented a lockout feature to prevent people from brute-forcing the combination. Although it isn’t wireless, it’s significantly simpler.

[thanks Michael]

Carnivorous Robots

June 26, 2009 by Caleb Kraft 30 Comments

flypaperup

Artists [James Auger] and [Jimmy Loizeau] have put out this display of carnivorous robots. Pictured above is a clock that is powered by a microbial fuel cell. The clock is equipped with a scroll of sticky paper for catching the flies which it then scrapes into it’s cell for digestion. The other pieces include a mouse eating coffee table, a strange mechanism for stealing spider’s meals, and a lamp shade inspired by pitcher plants.