You can access everything under /proc/sys through the sysctl interface. This
is mostly useful for C programs, which can use the sysctl function. Try
'man 2 sysctl' for more information.

As each chip gets its own directory under /proc/sys/dev/sensors, you must
somehow know the sysctl id of these directories to access the sensor data.
This is done through the file /proc/sys/dev/sensors/chips (see sensors.h
for the corresponding SYSCTL ids). You can only read this file; it 
returns an array of struct sensors_chips_data, as defined in sensors.h.
Each chip will have its own entry here, with both its sysctl id and
the corresponding /proc name.