/* An example analogue meter using a ST7735 TFT LCD screen This example uses the hardware SPI only Needs Font 2 (also Font 4 if using large scale label) Updated by Bodmer for variable meter size */ // Define meter size #define M_SIZE 0.667 #include // Hardware-specific library #include TFT_eSPI tft = TFT_eSPI(); // Invoke custom library #define TFT_GREY 0x5AEB #define TFT_ORANGE 0xFD20 /* 255, 165, 0 */ 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 old_value[6] = { -1, -1, -1, -1, -1, -1}; int d = 0; void setup(void) { Serial.begin(57600); // For debug tft.init(); tft.setRotation(3); tft.fillScreen(TFT_BLACK); analogMeter(); // Draw analogue meter updateTime = millis(); // Next update time } void loop() { if (updateTime <= millis()) { updateTime = millis() + 35; // Update meter every 35 milliseconds // Create a Sine wave for testing d += 4; if (d >= 360) d = 0; value[0] = 50 + 50 * sin((d + 0) * 0.0174532925); //value[0] = random(0,100); //unsigned long tt = millis(); plotNeedle(value[0], 0); // It takes between 2 and 14ms to replot the needle with zero delay //Serial.println(millis()-tt); } } // ######################################################################### // Draw the analogue meter on the screen // ######################################################################### void analogMeter() { // Meter outline tft.fillRect(0, 0, M_SIZE*239, M_SIZE*131, TFT_GREY); tft.fillRect(1, M_SIZE*3, M_SIZE*234, M_SIZE*125, 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*150; uint16_t x1 = sx * M_SIZE*100 + M_SIZE*120; uint16_t y1 = sy * M_SIZE*100 + M_SIZE*150; // 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*150; int x3 = sx2 * M_SIZE*100 + M_SIZE*120; int y3 = sy2 * M_SIZE*100 + M_SIZE*150; // Yellow zone limits //if (i >= -50 && 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_GREEN); tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_GREEN); } // Orange zone limits if (i >= 25 && i < 50) { tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_ORANGE); tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_ORANGE); } // 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*150; x1 = sx * M_SIZE*100 + M_SIZE*120; y1 = sy * M_SIZE*100 + M_SIZE*150; // 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*150; switch (i / 25) { case -2: tft.drawCentreString("0", x0+4, y0-4, 1); break; case -1: tft.drawCentreString("25", x0+2, y0, 1); break; case 0: tft.drawCentreString("50", x0, y0, 1); break; case 1: tft.drawCentreString("75", x0, y0, 1); break; case 2: tft.drawCentreString("100", x0-2, y0-4, 1); 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*150; // 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*(3 + 230 - 40), M_SIZE*(119 - 20), 2); // Units at bottom right tft.drawCentreString("%RH", M_SIZE*120, M_SIZE*75, 4); // Comment out to avoid font 4 tft.drawRect(1, M_SIZE*3, M_SIZE*236, M_SIZE*126, 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) { tft.setTextColor(TFT_BLACK, TFT_WHITE); char buf[8]; dtostrf(value, 4, 0, buf); tft.drawRightString(buf, 33, M_SIZE*(119 - 20), 2); 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 // Calculate 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 + 24 * ltx) - 1, M_SIZE*(150 - 24), osx - 1, osy, TFT_WHITE); tft.drawLine(M_SIZE*(120 + 24 * ltx), M_SIZE*(150 - 24), osx, osy, TFT_WHITE); tft.drawLine(M_SIZE*(120 + 24 * ltx) + 1, M_SIZE*(150 - 24), osx + 1, osy, TFT_WHITE); // Re-plot text under needle tft.setTextColor(TFT_BLACK, TFT_WHITE); tft.drawCentreString("%RH", M_SIZE*120, M_SIZE*75, 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 + 150); // Draw the needle in the new postion, magenta makes needle a bit bolder // draws 3 lines to thicken needle tft.drawLine(M_SIZE*(120 + 24 * ltx) - 1, M_SIZE*(150 - 24), osx - 1, osy, TFT_RED); tft.drawLine(M_SIZE*(120 + 24 * ltx), M_SIZE*(150 - 24), osx, osy, TFT_MAGENTA); tft.drawLine(M_SIZE*(120 + 24 * ltx) + 1, M_SIZE*(150 - 24), 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); } }