voice amplifier

[boooleen]

Hello !
My project is to make a voice amplifier with a mic INMP441 and a speaker on a esp32 card.
So I use the i2s protocol to collect the data from the mic and I convert the data to a 8-bits integer to send it to the DAC and then send it to the speaker (with a PAM8403 between).
The problem is that I can't transmit the sound from my microphone correctly to the speaker, there is only an unpleasant noise coming out of it.
If you have any suggestion, it would really help me.
I join my code there :

Code: [Select all] [Expand/Collapse]

1. #include <driver/i2s.h>
2. #include<cmath>
3. #include <driver/dac.h>
4.  
5. #define I2S_WS 15        
6. #define I2S_SD 32
7. #define I2S_SCK 14
8.  
9. #define I2S_PORT I2S_NUM_0
10.  
11. void setup() {
12.   Serial.begin(115200);
13.   Serial.println("Setup I2S ...");
14.  
15.   delay(1000);
16.   i2s_install();
17.   i2s_setpin();
18.   i2s_start(I2S_PORT);
19.   delay(500);
20. }
21.  
22. void loop() {
23.   int16_t sample = 0;
24.   int bytes = i2s_pop_sample(I2S_PORT, (char*)&sample, portMAX_DELAY);
25.   if(bytes > 0){
26.     int partieEntiere =(int)floor((sample+3276-1)/256);  // convert to a 8-bit integer
27.     Serial.println(partieEntiere);
28.     dacWrite(25,partieEntiere);  //send to the DAC
29.   }
30. }
31. // config the i2s protocol
32. void i2s_install(){
33.   const i2s_config_t i2s_config = {
34.     .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX),
35.     .sample_rate = 44100,
36.     .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
37.     .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
38.     .communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
39.     .intr_alloc_flags = 0, // default interrupt priority
40.     .dma_buf_count = 8,
41.     .dma_buf_len = 64,
42.     .use_apll = false
43.   };
44.  
45.   i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
46. }
47.  
48. void i2s_setpin(){
49.   const i2s_pin_config_t pin_config = {
50.     .bck_io_num = I2S_SCK,
51.     .ws_io_num = I2S_WS,
52.     .data_out_num = -1,
53.     .data_in_num = I2S_SD
54.   };
55.  
56.   i2s_set_pin(I2S_PORT, &pin_config);
57. }

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[rpiloverbd]

I think your problem has nothing to do with your code. It is related to the hardware. I think you'd better post your schematic. If you have created a PCB, you can post your layout to the following forum:

https://www.pcbway.com/project/shareproject/

There are many expert designers hanging around that forum who may guide you in the right direction regarding your design.

[boooleen]

There is my shematic [/img]