We used a Radio Shack condensor microphone element (part no. 270-090C) in the circuit from Tom's Sound In example.

For those who may want to build this circuit, it's important to procure an appropriate audio op amp (we used an LM386).

Had a bit of trouble getting serial data in to Processing from the PIC with Spencer's mac, but the PC worked fine. (Not sure if it was the way I setup up serial in Processing or my Keyspan serial cable/software - sk1800).

The sensitivity of the mic wasn't as high as desired, and I tried different resistors on the pot to see if I could get better results, to no avail. Original intent was to track the loudness of a room (Firmware lab) over time, but we ended up only getting good readings when making sounds directly into the mic.

Marta and I also struggled for a while debugging the php script to populate a mySQL database, but we never could get it to work. We were able to get Processing to write data to a text file online with PHP. Attached below is the resulting datalog.txt (created by sending sensor values to a php file) after speaking into the mic:

I would like to take this further by having multiple mics in various locations send audio information (amplitude, frequency) wirelessly to a central repository.sk1800

datalog.txt

 
2005-12-05 03:12:16	1
2005-12-05 03:12:21	19
2005-12-05 03:12:26	19
2005-12-05 03:12:31	19
2005-12-05 03:12:35	19
2005-12-05 03:12:40	31
2005-12-05 03:12:45	1
2005-12-05 03:12:49	64
2005-12-05 03:12:54	350
2005-12-05 03:12:59	36
2005-12-05 03:12:03	36
2005-12-05 03:12:08	23
2005-12-05 03:12:12	19
2005-12-05 03:12:17	15
2005-12-05 03:12:21	14
2005-12-05 03:12:26	7
2005-12-05 03:12:30	11
2005-12-05 03:12:35	8
2005-12-05 03:12:39	8
2005-12-05 03:12:44	8
2005-12-05 03:12:49	8
2005-12-05 03:12:53	8
2005-12-05 03:12:58	8
2005-12-05 03:12:02	8
2005-12-05 03:12:07	8
2005-12-05 03:12:12	8
2005-12-05 03:12:16	8
2005-12-05 03:12:21	8
2005-12-05 03:12:25	8
2005-12-05 03:12:30	8
2005-12-05 03:12:34	8
2005-12-05 03:12:39	8
2005-12-05 03:12:43	8
2005-12-05 03:12:47	8
2005-12-05 03:12:52	8
2005-12-05 03:12:56	8
2005-12-05 03:12:01	8
2005-12-05 03:12:05	8
2005-12-05 03:12:10	54
2005-12-05 03:12:14	54
2005-12-05 03:12:19	54
2005-12-05 03:12:23	54
2005-12-05 03:12:28	54
2005-12-05 03:12:32	54
2005-12-05 03:12:37	54
2005-12-05 03:12:41	54
2005-12-05 03:12:46	54
2005-12-05 03:12:50	54
2005-12-05 03:12:54	54
2005-12-05 03:12:59	54
2005-12-05 03:12:03	54
2005-12-05 03:12:08	54
2005-12-05 03:12:12	54
2005-12-05 03:12:17	54
2005-12-05 03:12:21	54
2005-12-05 03:12:26	54
2005-12-05 03:12:30	0
2005-12-05 03:12:35	23
2005-12-05 03:12:39	23
2005-12-05 03:12:44	4
2005-12-05 03:12:48	25
2005-12-05 03:12:52	2
2005-12-05 03:12:57	2
2005-12-05 03:12:01	270
2005-12-05 03:12:06	270
2005-12-05 03:12:10	270
2005-12-05 03:12:15	270
2005-12-05 03:12:19	270
2005-12-05 03:12:24	3
2005-12-05 03:12:28	4
2005-12-05 03:12:33	7
2005-12-05 03:12:37	8
2005-12-05 03:12:42	3
2005-12-05 03:12:46	3
2005-12-05 03:12:51	4
2005-12-05 03:12:55	4
2005-12-05 03:12:59	4
2005-12-05 03:12:04	4
2005-12-05 03:12:08	4
2005-12-05 03:12:13	4
2005-12-05 03:12:17	3
2005-12-05 03:12:22	3
2005-12-05 03:12:26	4
2005-12-05 03:12:31	4
2005-12-05 03:12:35	4
2005-12-05 03:12:40	7
2005-12-05 03:12:44	7
2005-12-05 03:12:49	7
2005-12-05 03:12:53	2