// Sensor test bench on the Arduino Uno (the board you already own).
// Use it to check every module ALONE before it goes into the robot or drone:
// scans I2C and names what it finds, and prints the analog inputs once a second.
// Wiring: module SDA -> A4, SCL -> A5, VCC -> 5V (or 3.3V for 3.3 V-only boards), GND -> GND.
// Analog sensors (LM35, MQ-3, MQ-4, water, LDR, phototransistor) -> A0..A3.
// Serial Monitor at 115200. Type 'b' to beep a buzzer on pin 8, 'r' to toggle a relay on pin 7.
#include <Wire.h>

struct Known {
  uint8_t addr;
  const char *name;
};
static const Known KNOWN[] = {
    {0x20, "MCP23017"}, {0x29, "VL53L1X"}, {0x44, "SHT31"}, {0x48, "ADS1115 (ADDR=GND)"},
    {0x49, "ADS1115 (ADDR=VDD)"}, {0x57, "MAX30102"}, {0x5A, "MLX90614"}, {0x62, "SCD40"},
    {0x68, "MPU6050"}, {0x76, "BME680 (SDO=GND)"}, {0x77, "BME680 (SDO=VDD)"},
};

static void scan() {
  Serial.println(F("--- I2C scan ---"));
  int found = 0;
  for (uint8_t a = 1; a < 127; a++) {
    Wire.beginTransmission(a);
    if (Wire.endTransmission() != 0) continue;
    found++;
    const char *name = "unknown";
    for (const Known &k : KNOWN)
      if (k.addr == a) name = k.name;
    Serial.print(F("0x"));
    if (a < 16) Serial.print('0');
    Serial.print(a, HEX);
    Serial.print(F("  "));
    Serial.println(name);
  }
  if (!found) Serial.println(F("nothing found: check SDA/SCL, power and pull-ups"));
}

void setup() {
  Serial.begin(115200);
  Wire.begin();
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  scan();
}

void loop() {
  static uint32_t at = 0;
  if (millis() - at > 1000) {
    at = millis();
    for (int ch = 0; ch < 4; ch++) {
      float v = analogRead(A0 + ch) * 5.0 / 1023.0;
      Serial.print(F("A"));
      Serial.print(ch);
      Serial.print(F("="));
      Serial.print(v, 2);
      Serial.print(F("V  "));
    }
    Serial.print(F("| LM35 on A0 = "));
    Serial.print(analogRead(A0) * 500.0 / 1023.0, 1);
    Serial.println(F(" C"));
  }
  if (Serial.available()) {
    char c = Serial.read();
    if (c == 'b') tone(8, 2000, 200);
    if (c == 'r') digitalWrite(7, !digitalRead(7));
    if (c == 's') scan();
  }
}