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Barometric pressure and temperature are part of the weather forecast, so I made high-precision air pressure and temperature sensor and used the Wio terminal to display the pressure on the dial plate, meanwhile, the under of the screen displays the temperature and pressure values.
The value of pressure gets lower and lower as the height increases
- The barometric pressure situation can be represented by the dial colour.
- Each period can record 15 points of temperature degrees.
- High precision barometric pressure and temperature detection.
Hardware required
Hardware connection
Software Required
You can follow below the link to download the Arduino IDE and learn more about Wio Terminal.
Wio Terminal Firmware
Before you upload the code, you need to download the library to support the code. please check here.
- Install the DPS310-Pressure-Sensor library, please visit DPS310.
- Install the LCD screen Library Seeed_Arduino_LCD, please visit Wio Terminal LCD for more information.
Barometric Pressure sensor code
C/C++Barometric pressure sensor using Wio terminal to present the data
#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);
}
}
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