Designing, Simulating and Testing a Simple Radio Duty-Cycling Protocol for Contiki

A few days ago we featured [Marcus]’ Contiki port to the TI Launchpad, Contiki being an open source operating system dedicated to the Internet of Things created by [Adam Dunkels] at the SICS in Sweden. Part of [Marcus]’ work involved designing a simple radio duty-cycling protocol that achieves 3% idle listening duty cycle while allowing for an average 65ms latency with no prior contact or synchronization.

As a few readers may already know, it takes quite a lot of power for a wireless device to listen/send data. A platform therefore needs to have an algorithm that minimizes power consumption while allowing a (regular) planned data transfer. After creating his protocol named SimpleRDC, [Marcus] first simulated it using the Cooja simulator in order to check that it could perform as desired. He then implemented a real life test and checked the protocol’s performance by sniffing the SPI lines connecting his MSP430 to the wireless module and by monitoring the platform power consumption with his oscilloscope and a shunt resistor.

Slot loading Xbox 360

slot360

File this one under: “Wow, that’s even possible?” xbox-scene hacker [RDC] has been hard at work converting his Xbox 360 to slot loading. To start, He removed the slot loading drive from a blueberry iMac G3. The loading mechanism is the top half of the drive. He split this off and married it to the reading mechanism in the Xbox’s Hitachi drive. The difficult part came with getting the drive to properly signal when it had a disc. He put together a custom circuit to do the detection and has a thorough description of how he solved the problem.

[Thanks, bic]