NOTE: This project is has been discontinued, and is provided only for historical reference. Please see multichannel audio player 2 instead.

• Introduction
• Details

• Related Pages

Please see our intro to DTMF for important background information on DTMF.

For information about what this chip does, please see SSI202 DTMF Decoder Chip.

We assign each digital output from the SSI202 chip to control the voice of one performer:

digital output				for just this one voice
bit position	SSI202 pin	voice	performer	touch-tone key	tones
D1	1	V1	Star singer	1	697, 1209
D2	8	V2	Costar	2	697, 1336
D4	17	V3	Male chorus	4	770, 1209
D8	16	V4	Female chorus	8	852, 1336
none	none	none	none	D	941, 1633

Then, you can make the star and costar sing by turning on D1 and D2, which you get by hitting "3" on your telephone keypad, which generates tones 697 Hz and 1477 Hz. A moment later, you hit the "C" key, and the male chorus and female chorus join in.

Please note that the binary output of the SSI202 DTMF decoder is latched. When you send a burst of tones to make characters sing, they continue to sing until you send a burst of DTMF tones to change who is singing. In order to make everybody shut up, you must hit the "D" key, sending the 941 Hz and 1633 Hz tones, which causes the SSI202 to output all zeroes, turning off everything.

• multichannel audio player 1
• overall design
• tone control design [this page]
• schematic diagrams
• making the recording

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