ESP32とLDRモジュールで光の強さを読み取る

1// ─────────────────────────────────────────
2//   BlueGrays · bluegrays.com
3//   Reading Light Intensity with the ESP32 LDR Module
4// ─────────────────────────────────────────
5// Reads the analog output (AO) of the LDR module with the 12-bit ADC and
6// converts it to a 0-100 light percentage using the calibration values.
7// The result is printed to the Serial Monitor (115200 baud) every 0.5 s.
8//
9// Pins:
10//   GPIO 34 (classic ESP32) / GPIO 1 (ESP32-S2/S3) -> LDR module AO
11//   LDR module VCC -> 3V3, GND -> GND
12
13#if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32S3)
14  const int LDR_PIN = 1;   // ESP32-S2/S3: ADC1_CH0
15#else
16  // Classic ESP32 DevKit V1: ADC1_CH6, input-only. GPIO 1 clashes with Serial TX here
17  const int LDR_PIN = 34;
18#endif
19
20// Calibration: measure in your own room and enter the values here. On the LDR module the AO voltage
21// (and raw) DROPS as the light gets brighter.
22const int RAW_DARK  = 4000;  // Dark raw
23const int RAW_LIGHT = 100;   // Light raw
24
25void setup() {
26  Serial.begin(115200);
27  analogReadResolution(12);  // Force 12-bit
28  Serial.println("LDR Okuma / LDR Reading");
29  Serial.println("-----------------------------");
30}
31
32void loop() {
33  int raw = analogRead(LDR_PIN);
34  // Clip to the calibration range, dark = 0%
35  int clipped = constrain(raw, RAW_LIGHT, RAW_DARK);
36  int percent = map(clipped, RAW_DARK, RAW_LIGHT, 0, 100);
37
38  Serial.print("Raw: ");
39  Serial.print(raw);
40  Serial.print(" | Light: %");
41  Serial.println(percent);
42
43  delay(500);
44}
45