woensdag 25 juli 2012

Cat tweeter, order placed

Hi - your order is ready to ship!

SparkFun Electronics Order

Date Packed: 07/25/2012

Shipping Method: UPS Ground

Items shipping in this package:

Breakout Board for XBee Module x1
Logic Level Converter x1
Voltage Regulator - 3.3V x1
2mm 10pin XBee Socket x4
RFID Tag - 125kHz (retail pack of 5) x2
RFID Reader ID-12 (125 kHz) x1
RFID Reader Breakout x1
XBee 1mW Chip Antenna - Series 1 (802.15.4) x2
XBee Explorer USB x1

This is for my new tweeting cat project. The plan is to hook up the RFID Reader ID-12 to the XBee Series 1, and send data to the other XBee Series one which is hooked up using the XBee Explorer USB to my playstation 2, which will send tweets based on where the cat is. I'll put the RFID tags on the various places that the cat goes (drinks, litter box, other cat, cat toy, sleeping place, doorway, food bowl, et cetera). Biggest concern are the batteries, but I'll figure out what to do with that. Most likely it will need a harness to avoid the cat being entangled in wires, and to avoid the RFID chip getting into the water bowl.

dinsdag 10 juli 2012

High definition digital antenna

For some time I wanted to build an antenna for my high definition television. When the AT&T U-verse system stopped working, I decided now was the time. I was subscribed to Make magazine for a while, and they had a good description of a possible antenna. I had already bought the "75 to 300 ohm matching transformer with spade clips on one end and female F connector on other" so it was just a matter to put things together. I didn't want to waste clothes hangers, and I didn't have a nice piece of wood, so I went a step cheaper by using cardboard tape and European grounding wire. I connected the wires by twisting them together with pliers. The result is visible in the picture on the left.






On this picture you can see most of the back side, including the way I twisted the wires. I used black dots to mark the places where the screws would've been on the original, as you can tell, one of the wires slipped a little bit. I hooked the transformer up using European screw blocks, of which I removed the plastic to ensure better contact. The total price of this antenna was less than $5, although I hooked it up to the television using an expensive gold plated antenna cable that was over $50.

Making sure the television understood the input was from an antenna and not from cable and to scan for all the stations was slightly tricky to figure out, but after it had discovered two channels I knew it was working. In the end it found over 60 channels, all local, of which most are Asian for some reason.

Below a picture of the television screen using the antenna. As you can see it provides a flawless 720p high definition signal from KTVU-HD. My apologies for the camera flash.