Interfacing A Digital Rotary Switch

August 27, 2009 by Mike Szczys 19 Comments

digital_rotary_switch

[hw640] has put together a well written and detail packed explanation of how to interface with a digital rotary switch. These digital opto encoders have just two outputs with four possible logic levels (00, 10, 11, 01). The relative position of the switch is insignificant but the direction of rotation is what matters.

The short and dirty: Each of the switch’s 2 output pins is attached to a pin change interrupt on the microcontroller. Every time the switch moves it generates either a rising edge or a falling edge on one of the two pins; both edges cause an interrupt. By checking which pin caused the interrupt, then comparing the logic levels of the two pins after that interrupt, we can determine the direction the switch was rotated.

Although this explanation uses a PIC and code written in PicBasic Pro the concepts are discussed in the abstract and would easily be adapted to an AVR or another microcontroller of your choice.

Clever Stair Climbing Robot

July 2, 2009 by Gerrit Coetzee 22 Comments

[youtube=http://www.youtube.com/watch?v=QReb1hLfdbE]

Stairs are one of the most commonly faced mobility challenges for a robot. This robot’s design eliminates the need for a complex drive train or computer, and instead uses a clever mechanical design to climb stairs. Version three of the robot uses five servos modified for continuous rotation, a Picaxe28, sharp IR sensors, and bump sensors.

[via BotJunkie]

Ikea LED Matrix

June 28, 2009 by Zach Banks 9 Comments

8x8

[Spikenzie] has created an 8×8 LED array that fits inside an ikea frame. He multiplexed the 64 red LEDs on a PCB with connections on the back. He then used a MAX7129, an LED multiplexer and driver, driven by a PIC over SPI to do animations and play pong. He then encased the array in laser-cut cardboard and white acrylic to get large dots. This entire assembly was then placed inside an Ikea RIBBA picture frame. The result is an aesthetic homebrew display that is easy to control.

Related: 64pixels are enough

Automated Paintball Sentry

June 26, 2009 by Gerrit Coetzee 32 Comments

[youtube=http://www.youtube.com/watch?v=7vYKwih8Izk]

Reader, [Ben Godding], sends in the video for his senior design team’s automated paintball sentry. The frame is made of plasma cut aluminum. The paintball gun uses a custom hopper mounted remotely from the gun body. It has two webcams offering a 160 degree field of vision, and the image processing is done by a dual core pentium CPU booting windows xp off a compact flash card. The computer interfaces with the 1/4scale RC servos using a PIC24. The paintball sentry can either be configured via a computer GUI when a monitor is available or a baclkit keypad and 4×20 charachter display in the field.

Related: [Jared Bouck]’s paintball gun turret

Persistence Of Vision Propeller Clock

June 13, 2009 by Gerrit Coetzee 12 Comments

[Jon Stanley] has a nice write up on a POV propellor clock powered by a PIC microcontroller. He improved on the original design by [Bob Blick]. Jon tried a few different methods of powering the spinning circuit, some of which could be handy for other projects. As a double plus good bonus, schematics and code are all linked on the site. This clock would look nice and sinister sitting on any mad scientist’s dresser.

Playing With The PC-PIC II

June 8, 2009 by Caleb Kraft 10 Comments

[youtube=http://www.youtube.com/watch?v=f09tA7sUbF4]

[Asier] pointed us to this video of his PC-PIC II acting as a peripheral to his EEepc. You can see him playing pong, using it as a musical input, and even a video game controller. This project seems pretty nice, though we would like some more information. We tried digging around in the “projects” area and couldn’t find anything.

HVACMonitor: Web Enabled Monitoring

May 19, 2009 by Caleb Kraft 12 Comments

hvac

[Marc] submitted this project he’s been building. It’s a web enabled HVAC monitoring system. He’s using a pic-web development board with a custom I/O daughter board to control the HVAC system. The project allows for the system to be monitored and controlled via the web. It should be able to interface with most commercial and residential systems. As usual, schematics and source files are available on his site.