Hello, everyone! Hope everything is ok!
I’m having a problem with prototyping: i want to use a standalone atmega328 to power a HC-SR04 to give me the distance from some objects when i press a button, then show the distance in a 16X2 LCD. However, whenever i power the atmega, there’s nothing on the serial monitor and nothing on the LCD (the letters appeared one time, but when i unplugged and plugged it again they never appeared again).
Things to keep in mind:
- I do use a USB to TTL converter
- I se an external bootloader that works, as i tested the “blink” example on the standalone atmega and the led blinked normally
- I have the atmega setup with the 16MHz crystal, capacitors etc
- I’ll send the code and images here, but pinning is as follows:
USB/TTL: - RX on 0 (pin 2 of atmega) - TX on 1 (3)
HC-SR04: - trig on 2 (4) -echo on 3 (5)
LCD with I2C (skech dosen’t have I2C but real one does): - SDA on A4 (27) - SCL on A5 (28)
Here’s the code:
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
int trig = 2;
int echo = 3;
int botao = 4; // botão no pino 4
void setup() {
Serial.begin(9600);
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);
pinMode(botao, INPUT_PULLUP); // botão com resistor interno de pull-up
// Inicializa o LCD
lcd.begin();
lcd.backlight();
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Pressione o botao");
}
void loop() {
// Espera o botão ser pressionado (nível LOW porque tem pull-up)
if (digitalRead(botao) == LOW) {
long duration;
float mm, soma = 0;
// Mensagem de medindo
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Medindo...");
// Faz 100 medições
for (int i = 0; i < 100; i++) {
digitalWrite(trig, LOW);
delayMicroseconds(2);
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);
duration = pulseIn(echo, HIGH);
mm = (duration / 29.0 / 2.0) * 10.0; // agora em milímetros
soma += mm;
delay(20); // intervalo entre medições
}
// Média das 100 medições
float media = soma / 100.0;
// Mostra no Serial Monitor
Serial.print(media, 1);
Serial.println(" mm");
// Mostra no LCD
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Distancia media:");
lcd.setCursor(0, 1);
lcd.print(media, 1);
lcd.print(" mm");
delay(1000); // evita repetir rápido se botão ficar pressionado
}
}
Could you guys help me figure it out what i’m doing wrong? I’m a novice in this.
Thanks in advance!
