Hack a Day » parallaxpropeller

Robotic gardener takes its cue from bomb disposal bots

Brian Benchoff — Mon, 01 Aug 2011 17:01:42 +0000

[Dave] posted some pictures and videos of his ‘Nuntius’ robot on the Propeller forums. From the pictures it’s an impressive build, but to really appreciate [Dave]‘s skill, check out the Youtube demo.

The controller is a Propeller protoboard with bits of angle aluminum fastened together. Pots are positioned at the joints of the remote’s arm so the robot’s arm can mirror the shape of the remote. We usually see Armatron bots controlled via computer, or in the rare case of human control, a mouse. [Dave]‘s build just might be one of the first remote manipulator builds we’ve seen on Hack A Day.

On the robot side of the equation, another Propeller board, motors, and servos are all powered by a 12 V motorcycle battery. Attached to the end of the manipulator is a cheap 2.4 Ghz wireless camera that [Dave] says makes you feel like you’re in the movie The Abyss. While we doubt this robot would be very good for underwater exploration, it does look like some of the Bomb Disposal robots we’ve seen.

Filed under: robots hacks, wireless hacks

Digital Audio on the Parallax Propeller

Brian Benchoff — Fri, 06 May 2011 11:05:41 +0000

[Beth] had the idea for transmitting digital audio over S/PDIF on a Propeller a few years ago, but only just got around to a writeup. For that, we thank her.

The writeup has a marvelous walkthrough of the S/PDIF protocol and the problems associated with with generating the signal. S/PDIF is a relatively resource-intensive protocol – the signal is clocked at 64x the audio sample rate. That signal is doubled for biphase mark code, keeping everything in sync. [Beth] says the microcontroller would neet at least 24 MIPS of processing power just to generate the S/PDIF signal – processing audio would be another task altogether. Because of the processing power needed, and the weird clock rates needed, [Beth] decided to go with the Propeller. The implementation uses only one core of the Propeller, leaving another seven cores available for sound synthesis or even a visualization over VGA.

[Beth] admits this could be done with just about any microcontroller (although it would need to be clocked at a multiple of 4.096 MHz for a 32kHz audio stream), but we really appreciate the work that went into bit-banging this signal.

Video of [Nick] at Gadget Gangster playing around with digital audio on a Propeller after the break.

Filed under: digital audio hacks, Microcontrollers

Coyote-1 guitar pedal available now

Eliot — Tue, 26 Aug 2008 23:45:00 +0000

OpenStomp’s Coyote-1 is now available for $349. The guitar effects pedal lets users design and upload their own effects to the device. It has two stomp switches with LEDs, an LCD display, and four user assignable knobs. The back has 1/4″ in/out and one selectable 1/4″. It also features NTSC composite out, a headphone jack, mini-USB for uploading, and an RJ11 I2C bus for expansion. The processor is a Parallax Propeller Chip. While the OS on the pedal is open source, the hardware design and effect design software are not. You can check out the source and product manual on their forum. If you’re more interested in breadboarding hardware, you might like the Beavis Board we covered earlier.

[via Create Digital Music]

Wii style controls for the Commodore 64

Eliot — Sun, 06 Jul 2008 04:00:00 +0000

[Jeff] has been playing around with Parallax’s Propeller chip. He’s used it to adapt an NES controller to the to the Commodore 64. In this latest iteration though, he’s added a Memsic 2125 dual axis accelerometer to the end of a whiffle ball bat and used that to provide Wii style controller input. The video above shows his son playing Street Sports Baseball with it.