pyFMRadio and auto-scanning

PyFMRadio, the N800 FM radio module for Python now supports automatic scanning for radio stations in the new release 0.20. The new version now also powers down the radio chip on close(), so it won't drain battery when the radio is not used.

Here's some example code for callback-based station scanning:

# import radio stuff
from FMRadio import FMRadio, FMRadioUnavailableError


stations = []


def scan_cb(freq, is_station):
    """
    Callback for scanning for stations. This callback is called for every
    frequency and tells you if a radio station was found.
    """

    print "scanning @ %0.2f MHz" % (freq / 1000.0),
    if (is_station):
        print "STATION FOUND"
        stations.append(freq)
    else:
        print ""
        
        

# open the radio
try:
    radio = FMRadio()
except FMRadioUnavailableError:
    # radio not available
    print "Your device doesn't seem to have a FM radio..."
    import sys; sys.exit(1)
    
# get frequency range; currently only the US/Europe frequency band is supported
# by the driver
low, high = radio.get_frequency_range()
print "Frequency range: %0.2f - %0.2f MHz" % (low / 1000.0, high / 1000.0)

# scan for radio stations
radio.scan(scan_cb)

# if we have found some stations, start playing
if (stations):
    radio.set_volume(50)
        
    print "Now listen to the radio."
    for freq in stations:
        print "Tuning in %0.2f MHz." % (freq / 1000.0)
        radio.set_frequency(freq)                
        import time; time.sleep(3)

else:
    print "No radio stations found. The signal is too weak."

# don't forget to shutdown the radio; this will also power down the radio chip
print "Switching off the radio."
radio.close()