Ned Konz / billy_bass

Program to record speech audio into RAM and then play it back, moving Billy Bass's mouth in sync with the speech.

Dependencies:   mbed

Remember Big Mouth Billy Bass?

I've made a simple demo program for him using the Freescale FRDM-KL25Z board. I've hooked up the digital I/O to his motor driver transistors and pushbutton switch.

This program records 1.8 seconds of speech audio from ADC input when the pushbutton is pressed, then plays the audio back with Billy Bass's mouth controlled so that it opens during vowel sounds.

The ADC input is driven from a microphone and preamplifier, via a capacitor and into a resistor divider connected to the +3.3V supply pin to provide mid-range biasing for the ADC signals.

The DAC output is connected to his audio amplifier input (to the trace that was connected to pin 10 of the controller IC). I had to provide a DC bias using the DAC to get the single transistor amplifier biased into proper operation.

For more on the method of vowel recognition, please see the paper: http://www.mirlab.org/conference_papers/International_Conference/ICASSP%201999/PDF/AUTHOR/IC991957.PDF

Y. Nishida, Y. Nakadai, Y. Suzuki, T. Sakurai, T. Kurokawa, and H. Sato. 1999.

Voice recognition focusing on vowel strings on a fixed-point 20-MIPS DSP board.

In Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 01 (ICASSP '99), Vol. 1. IEEE Computer Society, Washington, DC, USA, 137-140. DOI=10.1109/ICASSP.1999.758081 http://dx.doi.org/10.1109/ICASSP.1999.758081

Diff: main.cpp

Revision:
6:0217f58bff36
Parent:
5:9f4ffb2b0e6b
Child:
7:f0e5450449cb
--- a/main.cpp	Wed May 15 18:01:51 2013 +0000
+++ b/main.cpp	Wed May 15 23:23:55 2013 +0000
@@ -65,9 +65,11 @@
 
 void playAudioSample()
 {
+    static uint16_t dcBias = 0x4000;
     if (samplesRemaining) {
         int8_t val = *nextSample++;
-        speaker.write_u16((val + 128) << 8);
+        uint16_t val16 = dcBias + (val * 256);
+        speaker.write_u16(val16);
         samplesRemaining--;
     } else {
         sampleTicker.detach();
@@ -172,6 +174,8 @@
 void playWithBilly()
 {
     int8_t  *chunkStart = sampleBuffer;
+    head = true;
+    wait(0.2);
     for (uint16_t chunk = 0; chunk < NUM_CHUNKS; chunk++) {
         if (vowels[chunk]) {
             greenLED = 0.0;
@@ -183,6 +187,11 @@
         playAudio(CHUNK_DURATION_MS, chunkStart, CHUNK_SIZE);
         chunkStart += CHUNK_SIZE;
     }
+    tail = true;
+    wait(0.2);
+    tail = false;
+    wait(0.1);
+    head = false;
 }
 
 void dumpAudio(int8_t *start=sampleBuffer, uint16_t nsamples=SAMPLE_BUFFER_SIZE)
@@ -196,22 +205,27 @@
 {
     pc.baud(115200);
     pc.printf("\r\n\r\nSample buffer = %u samples; rate = %u Hz; period = %u usec\r\n", SAMPLE_BUFFER_SIZE, SAMPLE_RATE_HZ, SAMPLE_PERIOD_US);
-
+    pushbutton.mode(PullUp);
+   
     for (;;) {
         redLED = 1.0;
         greenLED = 1.0;
         blueLED = 1.0;
 
+#if 0
         pc.puts("ENTER when ready:");
         pc.getc();
         pc.puts("\r\n");
-
+#endif
 #if 0
         audioTest();
         playAudio(1000);
         analyze();
 #endif
 
+        while (pushbutton.read())
+            wait(0.1);
+
         recordAudio();
         float duration = timer.read();
         // playAudio(duration * 1000);