OC-protocol was written to include intelligent sensors to smart fabrics, in collaboration with UdK. The protocol is a simple bi-directional asynchronous protocol using one signal-wire, with a focus on time-scale compensation. Due to the increase in the prototyping using simple UART-less microprocessors, such as ATTINY, a protocol for communicating using minimal pin-count and time-scale independency was required.
The protocol uses open collector-hardware, as it is the most simple allowing for collision detection. It can be done with or without external components, making it also cost-effective. The protocol focuses on the time-scale differences of the master-processor (such as when using Arduino Uno or Lilypad, which have more precise clocks), and the sensor-processor, such as ATTINY85. Since the small processors are used with internal clocks, they tend to be imprecise. To compensate for this, the communication is initiated using a timed pulse, duration of which is known to both processors. Resulting communication is scaled to this time-frame.
OC-protocol has been used together with CANNON-protocol, and has been used with a few prototypes.