Tennis Ball Fetcher

tennisball

Reader [Julian von Mendel] and his team built this tennis ball fetching robot for a competition (translated). The first version used distance sensors to locate the tennis balls for pick-up, but they changed to a camera based approach. The robot has three omniwheels and is designed to calculate the shortest path to the ball despite orientation since it can rotate while traveling. The wheels are monitored using rotation sensors from PS/2 mice. The control is provided by 3 Atmel microcontrollers that communicate via SPI. The multiprocessor design is fairly generic and could be reused for a different style of robot. While their robot performed fairly well, there were some shortcomings. The limited storage space meant frequent trips to drop off balls. The tilting bucket kept them from picking up tennis balls that were against the wall. Also, the bot had to be disassembled for battery swaps. The project is very well documented and they’ve released all of their control code. You can see the robot retrieving a ball after the break. Continue reading “Tennis Ball Fetcher”

Flickering LED Circuit

Here’s a simple project for your Halloween celebration. The other day while looking through our box of Halloween decorations, we noticed that the incandescent lamp in one of the jack-o’-lanterns was burnt out. Instead of simply replacing the outdated bulb, we decided to build a small dark detecting circuit with 2 yellow LEDs based on this Evil Mad Scientist Laboratories design. After successfully building the circuit, we took the project one step further by incorporating an Atmel ATtiny13 microcontroller. The code switches the LEDs on and off randomly for a flickering effect and is based on this instructable. Below is the schematic we created in EAGLE and a parts list.

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Wireless Accelerometer Controlled RGB LED

[Andlier] sent us this cool little project.  He has built a wireless accelerometer controlled RGB LED lighting system. Based on what a mouth full that is, it sounds complicated right? The end result looks fairly intuitive. Simply pick up the controller and tilt your hand to change the color of the light.

The controller consists of an Atmel AVR168 microcontroller. He doesn’t specify what transceiver he is using, but if you look in the comments, he notes that he added an antenna to it to extend the range. The part that controls the LED is based off of an Atmel AVR169 microcontroller hooked to some shiftbright LED modules.

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Sanguino ATmega644P Board

The RepRap project, which is a printer that can make components using rapid prototyping technology, and it is designed so that it can eventually self replicate. Has released a new breakout board for the Sanguino that provides access to all the pins as screw terminals. The Sanguino is an Arduino compatible board based on the ATmega644P chip. You can populate the full board with all the components and have a fully functional single board. You could populate only the screw terminals and plug your Sanguino, and use it as a breakout board as well. The board design is released on Google Code.

Xbox 360 Battery Pack Teardown

Reader, [Fox9p3400], opened up an Xbox 360 controller battery pack so we could all see what goes into one. It contains two Sanyo 2100mAh NiMH AA rechargeables (Model HR-3U 1.2V). In addition to that, there is an Atmel microcontroller (not pictured) and the copper temperature probe you can see above. He has more pictures on Photobucket.

Amazingly Cheap Dual Channel Scope

[Jacques] sent us this little project he has been working on. It is an amazingly cheap USB 2 chanel scope. The total cost of the project was around 5 Euros.  It is based off of an Atmel Tiny45, has 2 analog inputs, and can supply 5 Volts to a breadboard. He has listed the bill of materials as well as downloads for the source code, plans, and display software.

ATmega88 Webserver

If you are an Atmel fan, you may enjoy this webserver built around the ATmega88. Since it has full TCP and HTTP support, communication can be done using a standard web browser on any system. We also noticed that the code uses AVR Libc and the processor can be replaced with an ATmega168, both used on the Arduino platform. Honestly, we think the most interesting part about this project is the firmware. The author has assumed that the webserver will only be sending one packet per request and the code is optimized for this setup. This leaves around 50% of the memory for the web application.

[via YourITronics]