If the command you need is not in python-OBDs tables, you can create a new OBDCommand object. The constructor accepts the following arguments (each will become a property).
| Argument | Type | Description |
|---|---|---|
| name | string | (human readability only) |
| desc | string | (human readability only) |
| mode | string | OBD mode (hex) |
| pid | string | OBD PID (hex) |
| bytes | int | Number of bytes expected in response |
| decoder | callable | Function used for decoding the hex response |
| supported (optional) | bool | Flag to prevent the sending of unsupported commands (False by default) |
When the command is sent, the mode and pid properties are simply concatenated. For unusual codes that don't follow the mode + pid structure, feel free to use just one, while setting the other to an empty string.
The decoder argument is a function of following form.
def <name>(_hex):
...
return (<value>, <unit>)The _hex argument is the data recieved from the car, and is guaranteed to be the size of the bytes property specified in the OBDCommand.
For example:
from obd import OBDCommand
from obd.utils import unhex
def rpm(_hex):
v = unhex(_hex) # helper function to convert hex to int
v = v / 4.0
return (v, obd.Unit.RPM)
c = OBDCommand("RPM", "Engine RPM", "01", "0C", 2, rpm)