雪寄せ時間を記録するためのM5StickCのプログラム

main.c

#include <Arduino.h>
#include <M5Unified.h>

static  float velocity = 0;


static void imu_task(void*)
{
  float offset = 0.09;
  int tap_size = 9;
  int b_ptr = 0;
  float z_buf[tap_size] = {0};
  float val[3];
  float vel = 0;
  float sum = 0;

  while(true) {
    M5.Imu.getAccel(&val[0], &val[1], &val[2]);
    vel = sqrt(val[0] * val[0] + val[1] * val[1] + val[2] * val[2]) - offset;

    sum -= z_buf[b_ptr];
    z_buf[b_ptr] = vel;
    sum += z_buf[b_ptr];
    b_ptr = (b_ptr + 1) % tap_size;
    
    velocity = sum / tap_size;

    delay(10);
  }
}

void setup() {
  auto cfg = M5.config();

  cfg.clear_display = true;  // default=true. clear the screen when begin.
  cfg.output_power  = false;  // default=true. use external port 5V output.
  cfg.internal_imu  = true;  // default=true. use internal IMU.
  cfg.internal_rtc  = false;  // default=true. use internal RTC.
  cfg.internal_spk  = false;  // default=true. use internal speaker.
  cfg.internal_mic  = false;  // default=true. use internal microphone.
  cfg.external_imu  = false;  // default=false. use Unit Accel & Gyro.
  cfg.external_rtc  = false;  // default=false. use Unit RTC.
  cfg.external_spk  = false; // default=false. use SPK_HAT / ATOMIC_SPK
//cfg.external_spk_detail.omit_atomic_spk = true; // omit ATOMIC SPK
//cfg.external_spk_detail.omit_spk_hat    = true; // omit SPK HAT
  cfg.led_brightness = 50;   // default= 0. system LED brightness (0=off / 255=max) (※ not NeoPixel)

  M5.begin(cfg);

  // Rotate LCD origin
  M5.Lcd.setRotation(1);
  M5.Lcd.setTextSize(2);

  // LED OFF
  pinMode(GPIO_NUM_10, OUTPUT);
  digitalWrite(GPIO_NUM_10, HIGH);

  // IMU task
  xTaskCreatePinnedToCore(imu_task, "imu_task", 1024, NULL, 25, NULL, APP_CPU_NUM);
}

static void display() {
  int bar_height = 20;
  int h = M5.Lcd.height();
  int w = M5.Lcd.width();
  int y = h - bar_height;
  int value = 0;

  M5.Lcd.setCursor(1, 1);
  M5.Lcd.printf("V: %.4f", velocity);

  value = map((int)(velocity * 10000), 0, 20000, 0, w);
  Serial.println(value);
  value = constrain(value, 0, w);
  Serial.println(value);

  M5.Lcd.fillRect(0, y, w, bar_height, TFT_BLACK);
  M5.Lcd.fillRect(0, y, value, bar_height, TFT_GREEN);
  M5.Lcd.fillRect(0, y, 3, bar_height, TFT_WHITE);
}

void loop() {
  Serial.print(".");
  display();
  delay(200);
}

platformio.ini

[env:m5stick-c]
platform = espressif32
board = m5stick-c
framework = arduino
lib_deps = m5stack/M5Unified@^0.0.7
monitor_speed = 115200