A Python and Arduino library bridging between Open Sound Control (OSC) messages and devices on an I2C bus, easing the use of pythonosc.
The library allows software which can use the OSC protocol for real-time control of devices, which is commonly used in music and sound applications, to control hardware devices on an I2C bus, which typically wouldn't be network-enabled. It provides the building block for a Python server to listen for OSC messages arriving over UDP on topics and route them to the corresponding devices on an I2C bus, according to the topic set in the OSC header.
The I2CDevice in i2c_device.py allows both sides of the mapping to be defined. The arguments passed to its constructor determine the OSC topic on one hand, and the bus address and memory address on the device on the other hand.
The I2COscDispatcher class in i2c_osc_dispatcher.py acts as a wrapper around the Dispatcher class in the pythonosc package.
The Arduino library is in the arduino subdirectory. It provides a C++ class for receiving messages sent from the Python code.
See below examples/blocking_gateway.py for simple usage of both classes.
The OSC topics are in the format devices/Device class/Device number/Function Device class, Device number, and Function are specified by the user.
I2C Bus addressed comprise the address to which the device responds on the bus, and a base address in its logical memory space.
Every write will be of 8 bytes:
Messages are 8 bytes long in total.
- bytes for the value, as a signed little-endian integer.
- 4 bytes for time, which is used to indicate a future time for execution, in a format compatible with SMPTE. The format
[0h:2m:23s:12f]where the hour is in the MSB, and the LSB gives teh SMPTE frame in the range 0 .. 30. Each byte will be an unsigned integer. The time bytes are treated as unsigned.
The I2CDevice in i2c_device.py allows both sides of the mapping to be defined. All the examples are built to run together, with compatible settings:
- OSC topic "/devices/light/1/rgb"
- I2C device address 0x08
- Address 0x100 in the device's address-space.
The examples provided:
- blocking_gateway.py: A simple blocking server, making use of the I2CDevice and I2COscDispatcher classes.
- arduino_i2c_slave_example: Arduino programme that implements the device side of the protocol
- chuck_sample.ck: A programme in the language Chuck, which sends OSC messages to blocking_gateway.py