With the impending digital switchover, many of you will find yourselves not only in need of a new converter box, but an antenna as well. Just like everything else, there are plans out there on how to build your own. [William] has gone through the effort of documenting his design and build of a very nicely made version. He used PVC for the frame and a wire mesh or chicken wire reflector. Good job [William]
This is a pretty useful device. It is an IR controlled light dimmer. It goes in line with the main power and controls how much gets through to your light. You can adjust the brightness with a TV remote control. Finally, we can retire our clapper! These are commercially available, but making your own is just so much more fun. You may have to dig a little on their site for the schematics and programming. There are tons of other projects there as well so have fun. You can see a video of it in action after the break.
[Alanson Sample] and [Joshua R. Smith] have been experimenting with wireless power transfer for their sensing platform. Their microcontroller of choice is the MSP430, which we used on our e-paper clock. They chose it specifically for its ability to work with low voltages and they discus its specific behavior at different voltages. The first portion of their paper uses a UHF RFID reader to transmit to the sensor’s four stage charge pump. They added a supercap to provide enough power for 24 hours of logging while the node isn’t near a reader. For the second half of the paper, they use a UHF antenna designed for digital TV with the same circuit and pointed it at a television tower ~4.1km away. It had an open circuit voltage of 5.0V and 0.7V across an 8KOhm load, which works out to be 60uW of power. They connected this to the AAA battery terminals of the thermometer/hygrometer pictured above. It worked without issue. The thermometer’s draw on a lab power supply was 25uA at 1.5V.
It’s an interesting approach to powering devices. Do you have an application that needs something like this? For more on wireless power, checkout this earlier post on scratch building RFID tags.
[via DVICE]
You probably saw [Phillip Torrone] and [Limor Fried]’s twittering Kill A Watt earlier this week. It was an entry in the Core77/Greener Gadgets Design Competition. We saw a little bit about how it was assembled, but now they’ve posted a full guide to assembling the hardware. Each Kill A Watt gets an XBee radio that transmits back to a receiver that logs the power usage. The difficult part when putting this design together was the XBee required 50mA when transmitting. This is well above the Kill A Watt’s internal power supply. They remedied this by adding a 10,000uF supercap to act as a rechargeable battery. The daily twittering is just a side-effect of the project. The Kill A Watts transmit every 2 seconds, so you’ll get a very accurate report of your power usage. This is a great project for renters who can’t permanently modify their power infrastructure. Each Kill A Watt can support quite a few appliances since they’re rated for 15A, ~1800W.
[youtube=http://www.youtube.com/watch?v=2Cj-morKHPQ]
We’ve covered a couple of different ways of doing choreographed Christmas lights. The most basic being sound activated ones made from speakers, then the parallax controlled ones. This one uses the parallax microcontroller as well, but [prabbit22m] seems to have put some more effort into the construction and enclosure. The lights are all LED this time around and there are 18 outlets that can be individually controlled in a nice, safe enclosure. The choreography was done well too. The capabilities video is pretty impressive, it looks like he has managed to do some fading in and out. You can see it after the break.
[youtube=http://www.youtube.com/watch?v=P0hBCdMJ96g]
If you are interested in trying out some home automation, but don’t want to get into the potentially dangerous area of hacking your house wiring, consider these servo switches. These allow you to flip a switch, using a servo. They are clean, temporary, and fairly compact. You can purchase them at oomlout.com or download the designs and build your own.
[jwad650] wanted a remote controlled power strip. These are fairly expensive, with a single outlet running roughly $15. He was able to build a 6 outlet version for about $50. He is using an SIS-7c to decode signals from a universal remote. Each plug is individually controlled by a 3Amp relay. Be careful making this, there’s lots of nasty shock potential in that mess of wires. We recommend that you confine it in an enclosure as well. [jwad650] plans on adding an enclosure, as well as LED indicators and fuses. You can see a video of it in action after the break. If you want more information about working with relays, check out the working with relays writeup.
