I'm trying to implement audio output using R2R 8bit DAC and Arduino UNO.
This is my hardware:
This is the sound i want to hear:
This is a wav file, 16Khz, mono, 8 bit pcm.
I used matlab to retrieve the binary data from the wav file, and then wrote this code:
http://csharppad.com/gist/0f39da965e31fc838c6de73ff50e5669
I connected the output to some speaker and what i hear is some strange sound..do you think i miss something in my hardware/software?
Thanks!
OP's Circuit
Part of the code
#include <avr/pgmspace.h>
int ledPins[8] = {0,1, 2, 3, 4, 5, 6, 7};
const byte sound[] PROGMEM = {128,
128, 128, 128, 127, 128, 127, 128, 127, 128, 127, 128, 128};
int pin, i;
void setup() {
for(pin=0; pin<=7; pin++)
pinMode(ledPins[pin], OUTPUT);
}
void loop() {
for (i=0; i<sizeof(sound); i++)
{
PORTD=sound[i];
delay(0.0625);
}
delay(2000);
}
Why are you have delay(0.0625); delay function only accept integer number.
You can use delayMicroseconds() function if you need less than millisecond delay.
R2RDAC.ino (54.1 KB)
billhowl:
OP's Circuit
Part of the code
#include <avr/pgmspace.h>
int ledPins[8] = {0,1, 2, 3, 4, 5, 6, 7};
const byte sound[] PROGMEM = {128,
128, 128, 128, 127, 128, 127, 128, 127, 128, 127, 128, 128};
int pin, i;
void setup() {
for(pin=0; pin<=7; pin++)
pinMode(ledPins[pin], OUTPUT);
}
void loop() {
for (i=0; i<sizeof(sound); i++)
{
PORTD=sound[i];
delay(0.0625);
}
delay(2000);
}
Why are you have delay(0.0625); delay function only accept integer number. You can use delayMicroseconds() function if you need less than millisecond delay.
Ok i didn't know it... I will check it with delay microsecond.
Does the LM358's input common mode range include ground?
That's the only thing I can see that might be an issue- might need to ac couple the ladder to the amp and add a voltage div.
Mark S.
markba633csi:
Does the LM358's input common mode range include ground?
That's the only thing I can see that might be an issue- might need to ac couple the ladder to the amp and add a voltage div.
Mark S.
Ok now i hear something that close to the sound in the rate of it but it still a kind of noise/humming and not something close to voice...
I also noticed that if i remove the 220uf cap, 10nf cap and 10k resistor there is no difference in the sound i get..maybe the problem is in the op amp?