Merge pull request #2 from ladyada-piclaw/main

Add TFT bar graph demo for Feather ESP32-S2 TFT

Author: ladyada

examples/AS7331_TFT_demo/.none.test.only

@@ -0,0 +1,221 @@
+/*!
+ * @file AS7331_TFT_demo.ino
+ *
+ * TFT demo for AS7331 UV Spectral Sensor on Feather ESP32-S2 TFT
+ * Displays UVA, UVB, UVC readings as bar graphs with temperature
+ *
+ * Hardware:
+ *  - Adafruit Feather ESP32-S2 TFT
+ *  - AS7331 UV Sensor breakout (I2C)
+ *
+ * Written by Limor Fried/Ladyada for Adafruit Industries.
+ * BSD license, all text above must be included in any redistribution
+ */
+
+#include <Adafruit_AS7331.h>
+#include <Adafruit_GFX.h>
+#include <Adafruit_ST7789.h>
+#include <Fonts/FreeSansBold9pt7b.h>
+#include <Fonts/FreeSans9pt7b.h>
+#include <Wire.h>
+
+// Feather ESP32-S2 TFT built-in display
+Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);
+
+// AS7331 UV sensor
+Adafruit_AS7331 as7331;
+
+// Display layout constants (240x135 landscape)
+#define SCREEN_WIDTH 240
+#define SCREEN_HEIGHT 135
+
+// Bar graph layout
+#define BAR_X 48       // Left edge of bars (after labels)
+#define BAR_WIDTH 120  // Maximum bar width
+#define BAR_HEIGHT 22  // Height of each bar
+#define BAR_SPACING 6  // Space between bars
+
+// Y positions
+#define TITLE_Y 18
+#define UVA_BAR_Y 32
+#define UVB_BAR_Y (UVA_BAR_Y + BAR_HEIGHT + BAR_SPACING)
+#define UVC_BAR_Y (UVB_BAR_Y + BAR_HEIGHT + BAR_SPACING)
+#define TEMP_Y 128
+
+// Colors
+#define COLOR_UVA 0x780F    // Purple/violet
+#define COLOR_UVB 0x339F    // Bright blue
+#define COLOR_UVC 0x07FF    // Cyan
+#define COLOR_BAR_BG 0x2104 // Dark gray
+#define COLOR_TITLE 0xFFFF  // White
+
+// Fixed scale maximums (uW/cm2)
+#define UVA_MAX 500.0
+#define UVB_MAX 100.0
+#define UVC_MAX 50.0
+
+// Previous values for flicker-free updates
+float prevUVA = -1, prevUVB = -1, prevUVC = -1;
+float prevTemp = -999;
+
+void setup() {
+  Serial.begin(115200);
+  unsigned long start = millis();
+  while (!Serial && (millis() - start < 3000)) {
+    delay(10);
+  }
+
+  Serial.println(F("AS7331 UV Sensor TFT Demo"));
+
+  // Enable TFT power
+  pinMode(TFT_BACKLITE, OUTPUT);
+  digitalWrite(TFT_BACKLITE, HIGH);
+  pinMode(TFT_I2C_POWER, OUTPUT);
+  digitalWrite(TFT_I2C_POWER, HIGH);
+  delay(10);
+
+  // Initialize TFT
+  tft.init(135, 240);
+  tft.setRotation(3);
+  tft.fillScreen(ST77XX_BLACK);
+
+  // Draw title with nice font
+  tft.setFont(&FreeSansBold9pt7b);
+  tft.setTextColor(COLOR_TITLE);
+  tft.setCursor(0, TITLE_Y);
+  tft.print(F("Adafruit AS7331 UV Sensor"));
+
+  // Initialize I2C and sensor
+  Wire.begin();
+
+  if (!as7331.begin(&Wire)) {
+    Serial.println(F("Failed to find AS7331 sensor!"));
+    tft.setFont(&FreeSansBold9pt7b);
+    tft.setTextColor(ST77XX_RED);
+    tft.setCursor(20, 70);
+    tft.print(F("Sensor Error!"));
+    tft.setFont(&FreeSans9pt7b);
+    tft.setCursor(10, 95);
+    tft.print(F("Check wiring"));
+    while (1) {
+      delay(100);
+    }
+  }
+
+  Serial.println(F("AS7331 found!"));
+
+  // Configure sensor
+  as7331.setMeasurementMode(AS7331_MODE_CMD);
+  as7331.setGain(AS7331_GAIN_64X);
+  as7331.setIntegrationTime(AS7331_TIME_64MS);
+
+  drawStaticUI();
+}
+
+void drawStaticUI() {
+  tft.setFont(&FreeSansBold9pt7b);
+
+  // Bar labels
+  tft.setTextColor(COLOR_UVA);
+  tft.setCursor(2, UVA_BAR_Y + 16);
+  tft.print(F("UVA"));
+
+  tft.setTextColor(COLOR_UVB);
+  tft.setCursor(2, UVB_BAR_Y + 16);
+  tft.print(F("UVB"));
+
+  tft.setTextColor(COLOR_UVC);
+  tft.setCursor(2, UVC_BAR_Y + 16);
+  tft.print(F("UVC"));
+
+  // Bar backgrounds and outlines
+  tft.fillRect(BAR_X, UVA_BAR_Y, BAR_WIDTH, BAR_HEIGHT, COLOR_BAR_BG);
+  tft.fillRect(BAR_X, UVB_BAR_Y, BAR_WIDTH, BAR_HEIGHT, COLOR_BAR_BG);
+  tft.fillRect(BAR_X, UVC_BAR_Y, BAR_WIDTH, BAR_HEIGHT, COLOR_BAR_BG);
+
+  tft.drawRect(BAR_X - 1, UVA_BAR_Y - 1, BAR_WIDTH + 2, BAR_HEIGHT + 2,
+               COLOR_UVA);
+  tft.drawRect(BAR_X - 1, UVB_BAR_Y - 1, BAR_WIDTH + 2, BAR_HEIGHT + 2,
+               COLOR_UVB);
+  tft.drawRect(BAR_X - 1, UVC_BAR_Y - 1, BAR_WIDTH + 2, BAR_HEIGHT + 2,
+               COLOR_UVC);
+}
+
+void updateBar(int y, float value, float maxVal, uint16_t color,
+               float *prevValue) {
+  int fillWidth = (int)((value / maxVal) * BAR_WIDTH);
+  if (fillWidth > BAR_WIDTH)
+    fillWidth = BAR_WIDTH;
+  if (fillWidth < 0)
+    fillWidth = 0;
+
+  int prevFillWidth = 0;
+  if (*prevValue >= 0) {
+    prevFillWidth = (int)((*prevValue / maxVal) * BAR_WIDTH);
+    if (prevFillWidth > BAR_WIDTH)
+      prevFillWidth = BAR_WIDTH;
+    if (prevFillWidth < 0)
+      prevFillWidth = 0;
+  }
+
+  if (fillWidth != prevFillWidth) {
+    tft.fillRect(BAR_X, y, BAR_WIDTH, BAR_HEIGHT, COLOR_BAR_BG);
+    if (fillWidth > 0) {
+      tft.fillRect(BAR_X, y, fillWidth, BAR_HEIGHT, color);
+    }
+  }
+
+  // Numeric value to the right of bar
+  tft.fillRect(BAR_X + BAR_WIDTH + 4, y, 68, BAR_HEIGHT, ST77XX_BLACK);
+  tft.setFont(&FreeSans9pt7b);
+  tft.setTextColor(color);
+  tft.setCursor(BAR_X + BAR_WIDTH + 6, y + 16);
+  if (value < 10.0) {
+    tft.print(value, 2);
+  } else if (value < 100.0) {
+    tft.print(value, 1);
+  } else {
+    tft.print(value, 0);
+  }
+
+  *prevValue = value;
+}
+
+void updateTemperature(float temp) {
+  if (abs(temp - prevTemp) > 0.1) {
+    tft.fillRect(0, TEMP_Y - 14, SCREEN_WIDTH, 18, ST77XX_BLACK);
+    tft.setFont(&FreeSans9pt7b);
+    tft.setTextColor(ST77XX_YELLOW);
+    tft.setCursor(30, TEMP_Y);
+    tft.print(F("Temp: ")); tft.print(temp, 1);
+    tft.print(F(" C"));
+    prevTemp = temp;
+  }
+}
+
+void loop() {
+  float uva, uvb, uvc;
+
+  if (as7331.oneShot_uWcm2(&uva, &uvb, &uvc)) {
+    float temp = as7331.readTemperature();
+
+    Serial.print(F("UVA: "));
+    Serial.print(uva, 2);
+    Serial.print(F(" | UVB: "));
+    Serial.print(uvb, 2);
+    Serial.print(F(" | UVC: "));
+    Serial.print(uvc, 2);
+    Serial.print(F(" | Temp: "));
+    Serial.print(temp, 1);
+    Serial.println(F(" C"));
+
+    updateBar(UVA_BAR_Y, uva, UVA_MAX, COLOR_UVA, &prevUVA);
+    updateBar(UVB_BAR_Y, uvb, UVB_MAX, COLOR_UVB, &prevUVB);
+    updateBar(UVC_BAR_Y, uvc, UVC_MAX, COLOR_UVC, &prevUVC);
+    updateTemperature(temp);
+  } else {
+    Serial.println(F("Failed to read UV sensor!"));
+  }
+
+  delay(200);
+}