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.
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.
[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.
posted Mar 6th 2009 1:58pm by Ian
filed under: reviews
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.
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.
[Contraptionmaker] ran into a problem when putting plastic insulation over his windows during the winter. When you cover the windows from the inside to prevent drafts, your access to the stick that opens the blinds is cut off. His solution was to build an automatic blind opener from a cordless drill. He started with some motors he had around the house, but none of them were strong enough. The final solution was a $10 Black & Decker drill. After removing the handle and trigger to extend it, he made a simple wall mount for it. You may notice him soldering some batteries into it, in his directions. Those are just for backup, in case the power goes out. You can see a video of it in action after the break. If you want something triggered by an alarm, or for a different type of blind, we may be able to help you out.
[Andrew] made this DVD dispenser for his senior project in high school. It is using an ATmega8515 for the brains, and a custom coded driver for the LCD. As you can see in the video, after the break, you can select a DVD by various identifiers such as genre or title. It then pushes that DVD out of the rack so you can grab it. Right now, all the DVDs have to be placed in predetermined positions, but it’s not a bad start at all. Thanks for sending this in [Andrew].
[James] sent in this project in which he built a tiny computer with text based OS and a 3Km wireless link. The details are a bit scarce, but he used an N8VEM, a Propeller Pocket Term, a 4 line LCD and an RF Transceiver to build it. It runs CP/M, the text based operating system and uses less than a half of a watt, without the vga monitor. With a total cost of 145 and 4 serial ports for sensors, this thing could come in handy. Especially since its low power consumption could allow it to be solar powered. You may recall the N8VEM from an earlier post we did.
