Posts with «jitter» label

Arduino SPI Library Gains Transaction Support

Transaction SPI Timing

To prevent data corruption when using multiple SPI devices on the same bus, care must be taken to ensure that they are only accessed from within the main loop, or from the interrupt routine, never both. Data corruption can happen when one device is chip selected in the main loop, and then during that transfer an interrupt occurs, chip selecting another device. The original device now gets incorrect data.

For the last several weeks, [Paul] has been working on a new Arduino SPI library, to solve these types of conflicts. In the above scenario, the new library will generate a blocking SPI transaction, thus allowing the first main loop SPI transfer to complete, before attempting the second transfer. This is illustrated in the picture above, the blue trace rising edge is when the interrupt occurred, during the green trace chip select. The best part, it only affects SPI, your other interrupts will still happen on time. No servo jitter!

This is just one of the new library features, check out the link above for the rest. [Paul] sums it up best: “protects your SPI access from other interrupt-based libraries, and guarantees correct setting while you use the SPI bus”.

Filed under: Arduino Hacks
Hack a Day 01 Aug 21:01

Skube, a tangible radio

Skube is a music player that allows you to discover and share music.

There are two modes, Playlist and Discovery. Playlist plays the tracks on your Skube, while Discovery looks for tracks similar to the ones on your Skube so you can discover new music that still fits your taste. When Skubes are connected together, they act as one player that shuffles between all the playlists. You can control the system as a whole using any Skube.

The interface is designed to be intuitive and tangible. Flipping the Skube changes the modes, tapping will play or skip songs and flipping a Skube on its front face will turn it off.

The Skube is a fully functional device, not just a concept. It use a combination of Arduino, Max/MSP and an XBee wireless network.

This project was made by Andrew Nip, Ruben van der Vleuten, Malthe Borch, and Andrew Spitz. It was part of the Tangible User Interface module at CIID ran by Vinay Venkatraman, David Cuartielles, Richard Shed, and Tomek Ness.

You can read the details and see the inner workings of the Skube here.

Via:[Create Digital Music]


Arduino Blog 20 Sep 10:21