从具有相同地址的i2c传感器读取值

3 回答

• 0

  您应该阅读此设备的手册，可用here . 它在界面描述中说

  多个传感器接口可以连接到单个I2C总线 . 可以通过I2C接口写入所需的地址值（4到127）来配置各个传感器接口的总线地址，以通过I2C写操作注册地址0 . PC和Arduino示例支持更改单个传感器I2C地址 .

  所以你必须这样做

  • 插上第一个传感器

  • 将地址（例如0x41）写入该器件的寄存器0

  • 拔下传感器

  • 对所有使用不同地址的传感器重复1-2-3

  然后每个传感器将回复您设置的地址 .

  请注意

  由于接口板将始终响应地址0x04，因此必须将此地址视为为SingleTact保留 . 如果要将多个SingleTact接口连接到同一I2C总线，则必须将地址0x04视为无效

  所以，即使在这种情况下，RTFM建议是最重要的建议......

  回复于 2024-05-08T14:03:01+08:00
• 5

  您也可以使用I2C多路复用器 . 它们有自己的I2C地址，可以在自己的总线（广播域）上枚举四个传感器，以便可以在它们之间切换 . 您的编程需要依次明确选择每个传感器并跟踪它正在读取的传感器 . 切换后，I2C流量只会传递到选定的设备 . 当您运行额外布线时，这最适用于星型拓扑中的一组传感器 .

  我要走得更远，并说你甚至可以使用继电器来切换这些进出，或者是OR / NAND门 .

  回复于 2024-05-08T14:03:01+08:00
• -2

  你需要使用 Kalman Filter

  #include "Wire.h"                      // i2c library
      #include "BMP085.h"                   // bmp085 library, download from url link (1)
      #include "Tone.h"                      // tone library, download from url link (3)
      #include "stdlib.h"                    // we need that to use dtostrf() and convert float to string
      #include "stdarg.h"
  
      #define UART_SPEED  9600
      short SPEAKER_PIN1 = 11;               // Speaker output -
      short SPEAKER_PIN2 = 12;               // Speaker output +
      short LED_PIN = 13;
  
      Tone speaker1, speaker2;
      BMP085   bmp085 = BMP085();            // BMP085 sensor
  
      const float SEA_LEVEL_PRESSURE = 101325;    // Pressure at sea level (Pa)
      const float KF_VAR_MEASUREMENT = 0.1;       // Variance of pressure measurement noise.
      const float KF_VAR_ACCEL = 0.75;             // Variance of pressure acceleration noise input.
  
      float CLIMB_TONE2_MULT;
      float SINK_TONE2_MULT;
  
      float   kf_x_abs,
              kf_x_vel,
              kf_p_abs_abs,
              kf_p_abs_vel,
              kf_p_vel_vel,
              kf_var_accel;
  
      #define VARIOS_LEN  5
      int varios[VARIOS_LEN];
      int varios_pos = 0, varios_sum = 0;
  
      void p(char *fmt, ... ){
          char tmp[128]; // resulting string limited to 128 chars
          va_list args;
          va_start (args, fmt );
          vsnprintf(tmp, 128, fmt, args);
          va_end (args);
          Serial.print(tmp);
      }
  
      void kf_reset(float abs_value, float vel_value) {
          kf_x_abs = abs_value;
          kf_x_vel = vel_value;
          kf_p_abs_abs = 1000000000;
          kf_p_abs_vel = 0;
          kf_p_vel_vel = KF_VAR_ACCEL;
          kf_var_accel = KF_VAR_ACCEL;
  
          varios_sum = 0;
          for (int i = 0; i < VARIOS_LEN; i++) varios[i] = 0;
          varios_pos = 0;
      }
  
      void setup() {
          Serial.begin(UART_SPEED);            // set up arduino serial port
          Wire.begin();                        // lets init i2c protocol
          speaker1.begin(SPEAKER_PIN1);        // piezo speaker output -
          speaker2.begin(SPEAKER_PIN2);        // piezo speaker output +
          digitalWrite(SPEAKER_PIN2, LOW);
  
          bmp085.init(MODE_ULTRA_HIGHRES, SEA_LEVEL_PRESSURE, false);
  
          kf_reset(SEA_LEVEL_PRESSURE, 0);
  
          CLIMB_TONE2_MULT = pow(2, 9/12);
          SINK_TONE2_MULT = pow(2, 1/12);
  
          welcome();      //everything is ready, play "welcome" sound
      }
  
      void welcome() {
          speaker1.play(300, 50);     // (note, duration)
          delay(100);
          speaker2.play(300, 50);     // (note, duration)
          delay(100);
          Serial.println("Vario is ready");
      }
  
      float pressure2altitude(float pressure) {
          return (float)44330 * (1 - pow(((float)(pressure)/SEA_LEVEL_PRESSURE), 0.190295));
      }
  
      float last_time = 0;
      void update_pressure() {
          long pressure;
          bmp085.calcTruePressure(&pressure);
  
          float time = millis();
          float dt = (time - last_time) / 1000;
          last_time = time;
  
          /* Kalman Filter code */
          kf_x_abs += kf_x_vel * dt;
  
          kf_p_abs_abs += (float)2 * dt * kf_p_abs_vel  +  dt * dt * kf_p_vel_vel  +  kf_var_accel * dt * dt * dt * dt / (float)4;
          kf_p_abs_vel +=                                       dt * kf_p_vel_vel  +  kf_var_accel * dt * dt * dt / (float)2;
          kf_p_vel_vel +=                                                          +  kf_var_accel * dt * dt;
  
          // Update state covariance. The last term mixes in acceleration noise.
          float y = pressure - kf_x_abs;                              // Innovation.
          float s_inv = 1.0 / (kf_p_abs_abs + KF_VAR_MEASUREMENT);    // Innovation precision.
          float k_abs = kf_p_abs_abs * s_inv;                         // Kalman gain
          float k_vel = kf_p_abs_vel * s_inv;
  
          // Update state estimate.
          kf_x_abs += k_abs * y;
          kf_x_vel += k_vel * y;
  
          // Update state covariance.
          kf_p_vel_vel -= kf_p_abs_vel * k_vel;
          kf_p_abs_vel -= kf_p_abs_vel * k_abs;
          kf_p_abs_abs -= kf_p_abs_abs * k_abs;
      }
  
      int avg_vario() {
          float altitude = pressure2altitude(kf_x_abs);
          int vario = (int)((altitude - pressure2altitude(kf_x_abs - kf_x_vel)) * 100);
  
          varios_sum += vario;
          varios_sum -= varios[varios_pos];
          varios[varios_pos] = vario;
  
          if (++varios_pos == VARIOS_LEN) varios_pos = 0;
          return varios_sum / VARIOS_LEN;
      }
  
  
      int CLIMB_RATE_START = 25,
          SINK_RATE_START  = -80;
  
      int loop_id = 0;
      unsigned long next_signal_time = 0;
      void loop() {
          update_pressure();
          int vario = avg_vario();
  
          unsigned long time = millis();
          if (time >= next_signal_time) {
              if (vario > CLIMB_RATE_START) {
                  long beep_period = 350 - vario / 2;
                  if (beep_period < 20) beep_period = 20;
  
                  int silence_period = beep_period / 16;
                  int tone = 1300 + vario;
                  if (tone > 2300) tone = 2300;
  
                  next_signal_time = time + beep_period + silence_period;
                  speaker1.play(tone, beep_period);
  
                  Serial.print("CLIMB  beep:");
                  Serial.print(beep_period);
                  Serial.print("    silence:");
                  Serial.print(silence_period);
                  Serial.print("    vario: ");
                  Serial.println(vario);
              } else if (vario < SINK_RATE_START) {
      //            int beep_period = 350 * 50 / (-vario);
      //            int silence_period = beep_period / 5;
                  int beep_period = 350 + vario / 2;
                  if (beep_period < 20) beep_period = 20;
                  int silence_period = beep_period / 16;
                  int tone = 1000 + vario;
                  if (tone < 300) tone = 300;
  
                  next_signal_time = time + beep_period + silence_period;
                  speaker1.play(tone, beep_period);     // (note, duration)
  
                  Serial.print("SINK  beep:");
                  Serial.print(beep_period);
                  Serial.print("    silence:");
                  Serial.print(silence_period);
                  Serial.print("    vario: ");
                  Serial.println(vario);
              }
          }
  
          loop_id++;
          if ((loop_id % 10) == 0) {
              Serial.print("vario: ");
              Serial.println(vario);
          }
  
          if ((loop_id % 10) == 0) {
              digitalWrite(LED_PIN, LOW);
          }
          if ((loop_id % 10) == 5) {
              digitalWrite(LED_PIN, HIGH);
          }
      }
  

  回复于 2024-05-08T14:03:01+08:00