BuzzerFreq:

Author/Contact: miklos.maroti@vanderbilt.edu (Miklos Maroti, ISIS, Vanderbilt)

The BuzzerFreq component measures the buzzer frequency and sampling frequency
and the overall noise level of the microphone and ADC. Many digital filters
are tuned to specific sampling (and sound) frequencies, and different micro-
controllers work at different speeds (MICA and MICA2), so it is essential to
verify the observable frequencies for correct operation. Using this utility you
can also filter out obviously bad sensor boards with high noise level.

OPERATION:

1. Program one mote with the BuzzerFreqC component. Attach a sensor board with
   a buzzer and microphone
2. Program another mote with the GenericBase application, with node id 1973.
3. Turn them on, connect the base station to a PC. Please be silent while
   the motes are running.
4. On the PC run the following program:

	java isis.nest.printmsgs.PrintDiagMsgs

   The format of each line printed is

	<node id> "buzzer" <buzzer freq> <buzzer ampl> "sampling" <sampling freq> <noise>

   where

	<node id> is the node id of the testing mote
	<buzzer freq> is the frequency of the buzzer. Our sensor boards were
		between 4200 and 4700, most of them were between 4400 and 4500.
	<buzzer ampl> is the amplitude of the buzzer. 
		In close range it should be over 100.
	<samling freq> is the sampling frequency in continuous mode. On the MICA
		this should be around 15300. On the MICA2 it should be (around) 17727.
	<noise> the energy level when the buzzer is turned off. This value should
		be less than or equal to 3.
