The alternative example sketch for six different boat gauges came about due to an issue with original code.

Which I also came across and reported it under original project here.

The solution boils down to removing reliance on the needle bounding box coordinates which are pre-populate in the setup() method:

  while (a != 44) {
    x[i] = r * cos(rad * a) + sx;
    y[i] = r * sin(rad * a) + sy;
    x2[i] = (r - 20) * cos(rad * a) + sx;
    y2[i] = (r - 20) * sin(rad * a) + sy;

    i++;
    a++;

    // reset "a" on overflow
    if (a == 360) {
      a = 0;
  }

• For live demonstration visit [https://www.youtube.com/watch?v=y_H7HM0oyoo]
• For original code visit VolosR/BoatGauges
• For original code with comments visit iiminov/BoatGauges

1. Install ESP32 boards library guide from randomnerdtutorials
2. Install TFT_eSPI library by Bodmer through Library Manager (Sketch > Include Library > Manage Libraries or Ctrl+Shift+l)

Open ..\Documents\Arduino\libraries\TFT_eSPI\User_Setup.h and comment out line 44:

//#define ILI9341_DRIVER

On line 64 uncomment GC9A01 driver:

#define GC9A01_DRIVER

Open ..\Documents\Arduino\libraries\TFT_eSPI\User_Setup_Select.h and comment out line 24:

//#include <User_Setups/Setup1_ILI9341.h>

On line 105 uncomment GC9A01 setup:

#include <User_Setups/Setup200_GC9A01.h>

Open ..\Documents\Arduino\libraries\TFT_eSPI\User_Setups\Setup200_GC9A01.h and update pin assignments:

#define TFT_MISO 5
#define TFT_MOSI 2
#define TFT_SCLK 15  // Clock pin
#define TFT_CS   17  // Chip select control pin
#define TFT_DC   16  // Data Command control pin
#define TFT_RST  4   // Reset pin (could connect to Arduino RESET pin)

Image is courtesy of WOKWI.com and some MS Paint work

ESP32     GC9A01
3V3       VCC
GND       GND
D15       SCL
D2        SDA
D4        RES
RX2       DC
TX2       CS
D5        BLK