Parts: 4×4 RGB Button Pad Controller SPI

March 9, 2009 by Ian 2 Comments

We covered SparkFun’s new RGB button pad controller a few weeks ago. This is a full-color clone of the monome interface; a 4×4 grid of buttons with tri-color LEDs underneath. Each LED has 24bits of color control, for more than 16million color combinations. Up to 10 panels can be chained together to create huge button grids, like SparkFun’s Tetris table. We previously used a smaller version in our RGB combination lock.

We asked SparkFun to send us the SPI version of the button controller to test. This is a new product developed in-house at SparkFun, with open source hardware and software. Read about our experience interfacing this board below.

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Motion Detecting Cat Toy

March 9, 2009 by Caleb Kraft 15 Comments

[youtube=http://www.youtube.com/watch?v=DFX8vSw42DY]

We love our pets, but sometimes we just can’t keep up with them all the time. Sometimes, we need some automated playmates for our furry pals. [Kateham] has built a motion detecting cat toy to keep their cat content and active. Their price list was roughly $5 for the whole project, but they did obtain things like microcontrollers from family members. Some places they did manage to cut costs were to harvest various parts from a VHS deck. Its great to see kids not only hacking, but recycling as well. Great job [Kateham]. This project is like a simpler version of the laser pup.

Model Rocket GPS And Data Logger

March 8, 2009 by Caleb Kraft 23 Comments

datalogger

Serious rocket hobbyists aren’t content with merely launching their rockets into the air. [wwgd] wants to have an on board computer to control his flights and log the data. He doesn’t quite know how to do it all yet, so he’s starting with the basics. He has built the basic GPS data logger using an accelerometer, a GPS unit, and a BS2P microcontroller. The overall weight is 62 grams and it can record for the whole 5 minute flight. At roughly $200 though, we’d be thinking twice before launching it into the stratosphere.

STK500 As An Arduino

March 8, 2009 by Eliot 5 Comments

stkarduino

The AVR STK500 has been Atmel’s standard AVR development platform for many years. Recently though, hobbyists have embraced the Arduino. [Alessandro] has decided to bring the two together so that you can use the Arduino environment with the STK500. Unlike the Arduino, it comes with 8 LEDs, 8 switches, a variable power supply, and variable analog reference. It’s a great way to get hardware you might already have back into service.

Remote Image Processing In JavaScript

March 7, 2009 by Eliot 2 Comments

[youtube=http://www.youtube.com/watch?v=u3_cFel26J8]

[Tom] wrote in to tell us about his JavaScript project for motion detection. It ties together two ideas we’ve talked about recently. The first is doing image processing in-browser using Canvas(), which we’ve seen employed in captcha breaking. The second is offloading heavy processing to browsers, which we saw recently in the MapReduce implementation. [Tom] is using JavaScript to compare consecutive images to determine if there’s any motion. He did this as part of MJPG-Streamer, a program for streaming images from webcams. It can run on very limited hardware, but image processing can be very intensive. Doing the image processing in-browser makes up for this limitation and means that a custom client program doesn’t have to be written. You can find the code here and a PDF about the proof of concept.

Tools: Saleae Logic, Logic Analyzer

March 6, 2009 by Ian 65 Comments

A logic analyzer records bus communications between two chips. If you’ve ever had a problem getting two chips to talk, or wanted to reverse engineer a protocol, a logic analyzer is the tool you need to spy on the bus.

The Logic is a USB logic analyzer with eight channels and sampling rates up to 24MHz. Among hobby-level logic analyzers, the Logic has a good mix of features and decent sampling rates. We’ve been following Joe Garrison’s work on the Logic for a long time. If you’ve ever considered bringing a product to market, you can learn a lot from Joe’s blog that documents his development process.

When it debuted, the Logic was so popular that it was hard to buy one. It’s now widely available, and Saleae gave us one to try. Read our review below.

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New Battery For An HP50G

March 6, 2009 by Caleb Kraft 14 Comments

calc1

According to the author, the HP 50G is an awesome calculator. But as awesome as it is, it is powered off of not-so-awesome AAA batteries. These little batteries don’t last long under the load of the calculators awesomeness, so a mod needed to be done. The battery chosen for installation was a replacement battery for a Sony PSP. He was able to find one, including the external charge regulator board for $10. Dropping it into the case and wiring it to charge off of the existing mini USB port looks fairly simple, very few actual modifications are necessary to the body. Unfortunately, they did end up with an LED protruding from the bottom that makes it wobble a bit, but they’re guessing that they get about 2x the battery life now.