Hello,
this is my first post in this forum. I am pretty new to this product and not very experienced in Arduino programing. So I need your help in order to finalize my project. I do need several gauges for my boat. So I decided to try the M5Stack which allows me to display 3 different gauges on one display by simply pressing one of the three buttons. As a start I used the example "TFT_Meter_linear". So far the functionality is given. However, I would like to rotate the scale and the pointer. The command "tft.setRotation()" doesn't do it. I would appreciate if someone could give me a hint on which values I have to manipulate in order to get the desired result. I have attached a picture of the current and the required display as well as the code
Best regards
image url)
An example analogue meter using a ILI9341 TFT LCD screen
Needs Font 2 (also Font 4 if using large scale label)
Make sure all the display driver and pin comnenctions are correct by
editting the User_Setup.h file in the TFT_eSPI library folder.
#########################################################################
###### DON'T FORGET TO UPDATE THE User_Setup.h FILE IN THE LIBRARY ######
#########################################################################
Updated by Bodmer for variable meter size
*/
// Define meter size as 1 for M5.Lcd.rotation(0) or 1.3333 for M5.Lcd.rotation(1)
#define M_SIZE 1.3333
#include <M5Stack.h>
#define ADC_Calibration_Value1 250.0 // For resistor measure 5 Volt and 180 Ohm equals 100% plus 1K resistor.
#define ADCpin1 35 // Potentiometer is connected to GPIO 35 (Analog ADC1_CH7)
// add a 1k Resistor from pin 35 to +5V and a Diode from GND to pin 35 (Cathode)
// a 10µf cap from GND to pin 35 may reduce a noisy needle
#define TFT_GREY 0x5AEB
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;
// variable for storing the potentiometer value
int potValue = 0;
void setup(void) {
M5.begin();
M5.Power.begin();
// M5.Lcd.setRotation(1);
// Serial.begin(57600); // For debug
M5.Lcd.fillScreen(TFT_BLACK);
analogMeter(); // Draw analogue meter
updateTime = millis(); // Next update time
}
//*****************************************************************************
// ReadADC is used to improve the linearity of the ESP32 ADC see: https://github.com/G6EJD/ESP32-ADC-Accuracy-Improvement-function
double ReadADC(byte pin) {
double reading = analogRead(pin); // Reference voltage is 3v3 so maximum reading is 3v3 = 4095 in range 0 to 4095
if (reading < 1 || reading > 4095) return 0;
// return -0.000000000009824 * pow(reading,3) + 0.000000016557283 * pow(reading,2) + 0.000854596860691 * reading + 0.065440348345433;
return (-0.000000000000016 * pow(reading, 4) + 0.000000000118171 * pow(reading, 3) - 0.000000301211691 * pow(reading, 2) + 0.001109019271794 * reading + 0.034143524634089) * 1000;
}
// Added an improved polynomial, use either, comment out as required
void loop() {
potValue = ReadADC(ADCpin1) * ADC_Calibration_Value1 / 4096;
Serial.print(ReadADC(ADCpin1)); // print raw value
Serial.print(" "); // tab
Serial.println(potValue); // print final value
delay(200); // to smoothen the pointer
plotNeedle(potValue, 0);
}
// #########################################################################
// Draw the analogue meter on the screen
// #########################################################################
void analogMeter()
{
// Meter outline
M5.Lcd.fillRect(0, 0, M_SIZE*239, M_SIZE*126, TFT_GREY);
M5.Lcd.fillRect(5, 3, M_SIZE*230, M_SIZE*119, TFT_WHITE);
M5.Lcd.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;
// Green zone limits
if (i >= -50 && i < 0) {
M5.Lcd.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_GREEN);
M5.Lcd.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_GREEN);
}
// Red zone limits
if (i >= 0 && i <50) {
M5.Lcd.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_RED);
M5.Lcd.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
M5.Lcd.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;
switch (i / 25) {
case -2: M5.Lcd.drawCentreString("40", x0, y0 - 12, 2); break;
case -1: M5.Lcd.drawCentreString("20", x0, y0 - 9, 2); break;
case 0: M5.Lcd.drawCentreString("CTR", x0, y0 - 7, 2); break;
case 1: M5.Lcd.drawCentreString("20", x0, y0 - 9, 2); break;
case 2: M5.Lcd.drawCentreString("40", 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) M5.Lcd.drawLine(x0, y0, x1, y1, TFT_BLACK);
}
M5.Lcd.drawString("Port", M_SIZE*(5 + 230 - 40), M_SIZE*(119 - 20), 2); // Label at bottom right
M5.Lcd.drawString("STBD", M_SIZE*(5 + 60 - 40), M_SIZE*(119 - 20), 2); // Label at bottom left
M5.Lcd.drawCentreString("Rudder", M_SIZE*120, M_SIZE*70, 4); // Comment out to avoid font 4
M5.Lcd.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
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx - 1), M_SIZE*(140 - 20), osx - 1, osy, TFT_WHITE);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx), M_SIZE*(140 - 20), osx, osy, TFT_WHITE);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx + 1), M_SIZE*(140 - 20), osx + 1, osy, TFT_WHITE);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx), M_SIZE*(140 - 20), osx, osy, TFT_WHITE);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx + 1), M_SIZE*(140 - 20), osx + 1, osy, TFT_WHITE);
// Re-plot text under needle
M5.Lcd.setTextColor(TFT_BLACK);
M5.Lcd.drawCentreString("Rudder", M_SIZE*120, M_SIZE*70, 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 5 lines to thicken needle
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx - 1), M_SIZE*(140 - 20), osx - 1, osy, TFT_RED);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx), M_SIZE*(140 - 20), osx, osy, TFT_MAGENTA);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx + 1), M_SIZE*(140 - 20), osx + 1, osy, TFT_RED);
M5.Lcd.drawLine(M_SIZE*(120 + 20 * ltx), M_SIZE*(140 - 20), osx, osy, TFT_MAGENTA);
M5.Lcd.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);
}
}
``