[Rafael] built a system that uses radio frequency for communications. The code he was using with the inexpensive receiver/transmitter pairs already had some error correction but from time to time an entire message would be missed by the receiver. He set out to make these RF communications more robust.
A little more than a year ago we looked at using these same transmitters with an Arduino. [Rafael] has a similar setup but since they are unidirectional he chose to use two pairs for bidirectional communication (each operating at a different frequency to avoid interference). On one end, a computer transmits data to the Arduino which is in a remote location. His confirmation protocol relies on a randomly generated message identifier. The computer will continually transmit the same message. The Arduino continually receives these messages, comparing them with the last successfully received message. If they match, it is considered a successful data transfer and the Arduino transmits a confirmation back to the computer which then starts transmitting the next message.
This isn’t an application-specific protocol. For demonstration purposes [Rafael] built a quick home automation setup that uses it to operate a house lamp.
With 2400 LEGO bricks and a lot of patience, [Will Gorman] built a LEGO 3D printer. It’s similar to a RepRap or a Makerbot, but instead of extruding plastic, it uses pre-extruded building blocks (aka LEGO bricks). The grey wall extending far above the unit itself is a feed magazine which holds the raw material. A Java application takes an MLCad file and translates it into building instructions for the printer. Those instructions are then sent to the device via USB. See it happen after the break.
Now this just needs to be combined with the LEGO sorting machine for an inexhaustible supply of bricks.
Continue reading “3D printing with LEGO”
This setup helps to represent data in a meaningful way to for visually impaired people. It uses a combination of physical objects to represent data clusters, and audio feedback when manipulating those objects. In the video after the break you’ll see that the cubes can orient themselves to represent data clusters. The table top acts as a graphing field, with a textured border as a reference for the user. A camera mounted below the clear surface allows image processing software to calculate the locations for the cubes. Each cube is motorized and contains an Arduino and ZigBee module, listening for positioning information from the computer that is doing the video processing. Once in position, the user can move the cubes, with modulated noise as a measure of how near they are to the heart of each data cluster.
The team plans to conduct further study on the usefulness of this interactive data object. We certainly see potential for hacking as this uses off-the-shelf components that are both inexpensive, and easy to find. It certainly reminds us of a multitouch display with added physical tokens.
Continue reading “Data plotting for the visually impaired”
[Isaac] grabbed the motor from an old printer and used it to make a spider run up and down the wall for Halloween. A PIC 12F683 uses a MOSFET to drive the motor. The program loop has a little bit of dramatic flare to it, raising the arachnid with a bit of a jerky motion to give it some life, then wait for a time before quietly lowering the spider (hopefully onto an unsuspecting party-goer). The driver board is set up for two motors, making it easy to reuse in future projects. This is quite effective, and the only addition we might suggest is to add a couple of red LEDs as some glowing eyes.
Take a look at the finished product after the break.
Continue reading “Halloween props: Dancing spider”