High Precision Barometric Pressure sensor using the Wio terminal

Overview

The demo shows that the Grove- high precision pressure sensor DPS310 is fully compatible with the Wio terminal, and its measurement has high precision.
Features

The range of normal atmospheric pressure values can be display by the dial colour
with the time to display the temperature degrees
High precision barometric pressure and temperature detection
Hardware

Hardware Connection

software

if you do not have The Arduino IDE, please view The Get Started with Wio Terminal
Install the LCD screen Library Seeed_Arduino_LCD, please visit Wio Terminal LCD.
Install the DPS310-Pressure-Sensor Library #include <Dps310.h>, please visit DPS310-Pressure-Sensor.
Code

#include <Dps310.h>
#include <SPI.h>
#include <TFT_eSPI.h>       // Hardware-specific library
TFT_eSPI tft = TFT_eSPI(); 

#define TFT_GREY 0x5AEB
#define LOOP_PERIOD 35 // Display updates every 35 ms

Dps310 Dps310PressureSensor = Dps310();

#define M_SIZE 1.4

TFT_eSprite spr = TFT_eSprite(&tft);  // Sprite

float ltx = 0;    // Saved x coord of bottom of needle
uint16_t osx = M_SIZE * 120, osy = M_SIZE * 120; // Saved x & y coords
uint32_t updateTime = 0;       // time for next update

int old_analog =  -999; // Value last displayed

int value[6] = {0, 0, 0, 0, 0, 0};
int d = 0;

void setup(void) {
    tft.begin();
    tft.init();
    tft.setRotation(3);
    Serial.begin(57600); // For debug
    tft.fillScreen(TFT_WHITE);
    spr.createSprite(TFT_HEIGHT,TFT_WIDTH);
    spr.setRotation(3);

    Dps310PressureSensor.begin(Wire);
    analogMeter(); // Draw analogue meter

    updateTime = millis(); // Next update time
}


void loop() {
  float temperature;
  float pressure;
  uint8_t oversampling = 7;
  int16_t ret;

  ret = Dps310PressureSensor.measureTempOnce(temperature, oversampling);
  ret = Dps310PressureSensor.measurePressureOnce(pressure, oversampling);
  Serial.println(pressure);

    if (updateTime <= millis()) {
        updateTime = millis() + 35; // Update emter every 35 milliseconds

        // Create a Sine wave for testing
        d += 4;
        if (d >= 360) {
            d = 0;
        }
        ////////////////////////////////////////////////////////
        // this is a excmple, you just need to del '- 100050'
        ////////////////////////////////////////////////////////
        plotNeedle(pressure-100050, 0); // It takes between 2 and 12ms to replot the needle with zero delay
    }

delay(100);
    spr.fillSprite(TFT_WHITE);
    spr.createSprite(250, 40);
    spr.fillSprite(TFT_WHITE);
    spr.setTextColor(TFT_BLACK, TFT_WHITE);
    spr.setFreeFont(&FreeSansBoldOblique12pt7b);
    spr.drawNumber(temperature, 0, 0);
    spr.drawString(" °C", 30, 0);
    spr.drawNumber(pressure, 120,0);
    spr.drawString("Pa", 210,0); 
    spr.pushSprite(30, 190); 
    spr.deleteSprite();

}


// #########################################################################
//  Draw the analogue meter on the screen
// #########################################################################
void analogMeter() {

    // Meter outline
    tft.fillRect(0, 0, M_SIZE * 239, M_SIZE * 126, TFT_GREY);
    tft.fillRect(5, 3, M_SIZE * 230, M_SIZE * 119, TFT_WHITE);

    tft.setTextColor(TFT_BLACK);  // Text colour

    // Draw ticks every 5 degrees from -50 to +50 degrees (100 deg. FSD swing)
    for (int i = -50; i < 51; i += 5) {
        // Long scale tick length
        int tl = 15;

        // Coodinates of tick to draw
        float sx = cos((i - 90) * 0.0174532925);
        float sy = sin((i - 90) * 0.0174532925);
        uint16_t x0 = sx * (M_SIZE * 100 + tl) + M_SIZE * 120;
        uint16_t y0 = sy * (M_SIZE * 100 + tl) + M_SIZE * 140;
        uint16_t x1 = sx * M_SIZE * 100 + M_SIZE * 120;
        uint16_t y1 = sy * M_SIZE * 100 + M_SIZE * 140;

        // Coordinates of next tick for zone fill
        float sx2 = cos((i + 5 - 90) * 0.0174532925);
        float sy2 = sin((i + 5 - 90) * 0.0174532925);
        int x2 = sx2 * (M_SIZE * 100 + tl) + M_SIZE * 120;
        int y2 = sy2 * (M_SIZE * 100 + tl) + M_SIZE * 140;
        int x3 = sx2 * M_SIZE * 100 + M_SIZE * 120;
        int y3 = sy2 * M_SIZE * 100 + M_SIZE * 140;

        // Yellow zone limits
        if (i >= -50 && i < -25) {
          tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_GREEN);
          tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_GREEN);
        }
        
        if (i >= -25 && i < 0) {
          tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_YELLOW);
          tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_YELLOW);
        }

        // Green zone limits
        if (i >= 0 && i < 25) {
            tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_RED);
            tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_RED);
        }

        // Orange zone limits
        if (i >= 25 && i < 50) {
            tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_RED);
            tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_RED);
        }

        // Short scale tick length
        if (i % 25 != 0) {
            tl = 8;
        }

        // Recalculate coords incase tick lenght changed
        x0 = sx * (M_SIZE * 100 + tl) + M_SIZE * 120;
        y0 = sy * (M_SIZE * 100 + tl) + M_SIZE * 140;
        x1 = sx * M_SIZE * 100 + M_SIZE * 120;
        y1 = sy * M_SIZE * 100 + M_SIZE * 140;

        // Draw tick
        tft.drawLine(x0, y0, x1, y1, TFT_BLACK);

        // Check if labels should be drawn, with position tweaks
        if (i % 25 == 0) {
            // Calculate label positions
            x0 = sx * (M_SIZE * 100 + tl + 10) + M_SIZE * 120;
            y0 = sy * (M_SIZE * 100 + tl + 10) + M_SIZE * 140;

            ////////////////////////////////////////////////////////////
            //  In here, you can change the dial plate 
            ////////////////////////////////////////////////////////////
            switch (i / 25) {
                case -2: tft.drawCentreString("100000", x0, y0 - 12, 2); break;
                case -1: tft.drawCentreString("100025", x0, y0 - 9, 2); break;
                case 0: tft.drawCentreString("100050", x0, y0 - 7, 2); break;
                case 1: tft.drawCentreString("100075", x0, y0 - 9, 2); break;
                case 2: tft.drawCentreString("100100", x0, y0 - 12, 2); break;
            }
        }

        // Now draw the arc of the scale
        sx = cos((i + 5 - 90) * 0.0174532925);
        sy = sin((i + 5 - 90) * 0.0174532925);
        x0 = sx * M_SIZE * 100 + M_SIZE * 120;
        y0 = sy * M_SIZE * 100 + M_SIZE * 140;
        // Draw scale arc, don't draw the last part
        if (i < 50) {
            tft.drawLine(x0, y0, x1, y1, TFT_BLACK);
        }
    }

    //tft.drawString("%RH", M_SIZE * (5 + 230 - 40), M_SIZE * (119 - 20), 2); // Units at bottom right
    tft.drawCentreString("K/Pa", M_SIZE * 120, M_SIZE * 80, 4); // Comment out to avoid font 4
    tft.drawRect(5, 3, M_SIZE * 230, M_SIZE * 119, TFT_BLACK); // Draw bezel line

    plotNeedle(0, 0); // Put meter needle at 0
}

// #########################################################################
// Update needle position
// This function is blocking while needle moves, time depends on ms_delay
// 10ms minimises needle flicker if text is drawn within needle sweep area
// Smaller values OK if text not in sweep area, zero for instant movement but
// does not look realistic... (note: 100 increments for full scale deflection)
// #########################################################################
void plotNeedle(int value, byte ms_delay) {

    if (value < -10) {
        value = -10;    // Limit value to emulate needle end stops
    }
    if (value > 110) {
        value = 110;
    }

    // Move the needle until new value reached
    while (!(value == old_analog)) {
        if (old_analog < value) {
            old_analog++;
        } else {
            old_analog--;
        }

        if (ms_delay == 0) {
            old_analog = value;    // Update immediately if delay is 0
        }

        float sdeg = map(old_analog, -10, 110, -150, -30); // Map value to angle
        // Calcualte tip of needle coords
        float sx = cos(sdeg * 0.0174532925);
        float sy = sin(sdeg * 0.0174532925);

        // Calculate x delta of needle start (does not start at pivot point)
        float tx = tan((sdeg + 90) * 0.0174532925);

        // Erase old needle image
        tft.drawLine(M_SIZE * (120 + 20 * ltx - 1), M_SIZE * (140 - 20), osx - 1, osy, TFT_WHITE);
        tft.drawLine(M_SIZE * (120 + 20 * ltx), M_SIZE * (140 - 20), osx, osy, TFT_WHITE);
        tft.drawLine(M_SIZE * (120 + 20 * ltx + 1), M_SIZE * (140 - 20), osx + 1, osy, TFT_WHITE);

        // Re-plot text under needle
        tft.setTextColor(TFT_BLACK);
        tft.drawCentreString("K/Pa", M_SIZE * 120, M_SIZE * 80, 4); // // Comment out to avoid font 4
        
        // Store new needle end coords for next erase
        ltx = tx;
        osx = M_SIZE * (sx * 98 + 120);
        osy = M_SIZE * (sy * 98 + 140);

        // Draw the needle in the new postion, magenta makes needle a bit bolder
        // draws 3 lines to thicken needle
        tft.drawLine(M_SIZE * (120 + 20 * ltx - 1), M_SIZE * (140 - 20), osx - 1, osy, TFT_RED);
        tft.drawLine(M_SIZE * (120 + 20 * ltx), M_SIZE * (140 - 20), osx, osy, TFT_MAGENTA);
        tft.drawLine(M_SIZE * (120 + 20 * ltx + 1), M_SIZE * (140 - 20), osx + 1, osy, TFT_RED);

        // Slow needle down slightly as it approaches new postion
        if (abs(old_analog - value) < 10) {
            ms_delay += ms_delay / 5;
        }

        // Wait before next update
        delay(ms_delay);
    }
}
High Precision Barometric Pressure sensor using the Wio terminal

Overview​

Features​

Hardware​

Hardware Connection​

software​

Code​
