Build Instructions

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• 1

  WIRING PROCESS

  

  

  

  The first step in the entire process is to connect our power source, which is a 14500 3.7V 600mAh Li-ion cell with a PCM.

  The PCM has a DW01 Circuit that gives the cell low and high cut features, which are necessary for charging and discharging the cell correctly without causing a blast.

  • First, we connected the lithium cell's positive and negative terminals to the TTGO Board's positive and negative battery terminals.
  • Next, we attached a switch between the TTGo board and the battery connections. We soldered one end of the positive wire from the battery to the switch's NO terminal, and the switch's NC terminal is linked to the TTGO battery terminal's positive terminal. To break power between the battery and the TTGO board, we installed this switch between them.
• 2

  MAIN CODE

  

  This was the code we used in this project, and it’s definitely not the simplest one. First, I want to give a shout-out to the absolute legend nikthefix—thanks to the repository he made for this display, we were able to work with it without relying on the code provided by TTGO.

  We mostly followed the code structure from nikthefix’s repo and kept the AXS15231B header and implementation files, which handle communication with the display hardware, including sending pixels, drawing shapes, and initializing the screen.

  #include "AXS15231B.h" #include "pins_config.h" #include <WiFi.h> #include <NTPClient.h> #include <WiFiUdp.h> #define SCREEN_W 640 #define SCREEN_H 180 uint16_t frameBuffer[SCREEN_W * SCREEN_H]; #define RECT_WIDTH (SCREEN_W / 3) #define RECT_HEIGHT SCREEN_H int scale = 6; // bigger numbers #define GREEN 0xE007 #define BLACK 0x0000 const uint8_t font5x7[][5] = { {0x3E,0x51,0x49,0x45,0x3E}, // 0 {0x00,0x42,0x7F,0x40,0x00}, // 1 {0x42,0x61,0x51,0x49,0x46}, // 2 {0x21,0x41,0x45,0x4B,0x31}, // 3 {0x18,0x14,0x12,0x7F,0x10}, // 4 {0x27,0x45,0x45,0x45,0x39}, // 5 {0x3C,0x4A,0x49,0x49,0x30}, // 6 {0x01,0x71,0x09,0x05,0x03}, // 7 {0x36,0x49,0x49,0x49,0x36}, // 8 {0x06,0x49,0x49,0x29,0x1E}, // 9 }; // WiFi credentials const char* ssid = "add your SSID"; const char* password = "add your PASSWORD"; // NTP Client WiFiUDP ntpUDP; NTPClient timeClient(ntpUDP, "pool.ntp.org", 19800); // IST void drawCharScaled(uint16_t *buf, int w, int x, int y, char c, uint16_t color, uint16_t bg, int s){ if(c<'0' || c>'9') return; int idx = c - '0'; for(int col=0; col<5; col++){ uint8_t line = font5x7[idx][col]; for(int row=0; row<7; row++){ uint16_t px_color = (line & (1<<row)) ? color : bg; for(int dx=0; dx<s; dx++){ for(int dy=0; dy<s; dy++){ int px = x + col*s + dx; int py = y + row*s + dy; if(px<w && py<SCREEN_H) buf[py*w + px] = px_color; } } } } } void drawTextScaled(uint16_t *buf, int w, int x, int y, const char* text, uint16_t color, uint16_t bg, int s){ while(*text){ drawCharScaled(buf, w, x, y, *text, color, bg, s); x += (5+1)*s; text++; } } void fillRectBuffer(uint16_t *buf, int w, int x, int y, int rect_w, int rect_h, uint16_t color){ for(int j=0;j<rect_h;j++) for(int i=0;i<rect_w;i++) buf[(y+j)*w + (x+i)] = color; } void drawRectBuffer(uint16_t *buf, int w, int x, int y, int rect_w, int rect_h, uint16_t color){ for(int i=0;i<rect_w;i++){ buf[y*w + x + i] = color; buf[(y+rect_h-1)*w + x + i] = color; } for(int j=0;j<rect_h;j++){ buf[(y+j)*w + x] = color; buf[(y+j)*w + x + rect_w-1] = color; } } void setup() { pinMode(TFT_BL, OUTPUT); digitalWrite(TFT_BL, HIGH); axs15231_init(); Serial.begin(115200); WiFi.begin(ssid, password); Serial.print("Connecting to WiFi"); while(WiFi.status() != WL_CONNECTED){ delay(500); Serial.print("."); } Serial.println("\nWiFi connected"); timeClient.begin(); // Draw static rectangles once fillRectBuffer(frameBuffer, SCREEN_W, 0, 0, SCREEN_W, SCREEN_H, BLACK); drawRectBuffer(frameBuffer, SCREEN_W, 0, 0, RECT_WIDTH, RECT_HEIGHT, GREEN); drawRectBuffer(frameBuffer, SCREEN_W, RECT_WIDTH, 0, RECT_WIDTH, RECT_HEIGHT, GREEN); drawRectBuffer(frameBuffer, SCREEN_W, RECT_WIDTH*2, 0, RECT_WIDTH, RECT_HEIGHT, GREEN); lcd_PushColors_rotated_90(0,0,SCREEN_W,SCREEN_H, frameBuffer); } int prevHours=-1, prevMinutes=-1, prevSeconds=-1; void loop(){ if(timeClient.update()){ int hours = timeClient.getHours(); int minutes = timeClient.getMinutes(); int seconds = timeClient.getSeconds(); char buf[3]; int y_center = (SCREEN_H - 7*scale) / 2; // Only update digits that changed if(hours != prevHours){ sprintf(buf,"%02d", hours); fillRectBuffer(frameBuffer, SCREEN_W, 0, y_center, RECT_WIDTH, 7*scale, BLACK); drawTextScaled(frameBuffer, SCREEN_W, RECT_WIDTH/2 - scale*6, y_center, buf, GREEN, BLACK, scale); prevHours = hours; } if(minutes != prevMinutes){ sprintf(buf,"%02d", minutes); fillRectBuffer(frameBuffer, SCREEN_W, RECT_WIDTH, y_center, RECT_WIDTH, 7*scale, BLACK); drawTextScaled(frameBuffer, SCREEN_W, RECT_WIDTH + RECT_WIDTH/2 - scale*6, y_center, buf, GREEN, BLACK, scale); prevMinutes = minutes; } if(seconds != prevSeconds){ sprintf(buf,"%02d", seconds); fillRectBuffer(frameBuffer, SCREEN_W, RECT_WIDTH*2, y_center, RECT_WIDTH, 7*scale, BLACK); drawTextScaled(frameBuffer, SCREEN_W, RECT_WIDTH*2 + RECT_WIDTH/2 - scale*6, y_center, buf, GREEN, BLACK, scale); prevSeconds = seconds; } lcd_PushColors_rotated_90(0,0,SCREEN_W,SCREEN_H, frameBuffer); } }

  The code begins by adding Libraries and the custom header files that are required for Wi-Fi, NTP Server, pin definitions and Display initialization.

  The AXS15231B library handles the AXS15231 display, including initialization and drawing functions.

  pins_config Contains your pin definitions for the display, backlight, and other hardware connections.

  Wifi.h is the ESP32 Wi-Fi library for connecting to a wireless network.

  NTPClient is used for getting the current time from an NTP server over the internet.

  the WiFiUdp is the UDP protocol library required by NTPClient to fetch time.

  Display and Graphics Setup

   #define SCREEN_W 640#define SCREEN_H 180uint16_t frameBuffer[SCREEN_W * SCREEN_H];#define RECT_WIDTH (SCREEN_W / 3)#define RECT_HEIGHT SCREEN_Hint scale = 6; // scaling factor for bigger digits#define GREEN 0xE007#define BLACK 0x0000

  This section specifies the height and width of the screen, the rectangle width, the pixel buffer, and the digit scaling. Frame Pixel colors are saved in a buffer before being sent to the LCD. The RGB565 16-bit format is used to define colors.

  Font Definition

   const uint8_t font5x7[][5] = { {0x3E,0x51,0x49,0x45,0x3E}, // 0 {0x00,0x42,0x7F,0x40,0x00}, // 1 {0x42,0x61,0x51,0x49,0x46}, // 2 {0x21,0x41,0x45,0x4B,0x31}, // 3 {0x18,0x14,0x12,0x7F,0x10}, // 4 {0x27,0x45,0x45,0x45,0x39}, // 5 {0x3C,0x4A,0x49,0x49,0x30}, // 6 {0x01,0x71,0x09,0x05,0x03}, // 7 {0x36,0x49,0x49,0x49,0x36}, // 8 {0x06,0x49,0x49,0x29,0x1E}, // 9};

  The numbers 0–9 are represented by this 5x7 pixel representation, which was used to manually draw the digits on the framebuffer.

  WiFi & NTP Setup

   const char* ssid = "ADD YOUR SSID";const char* password = "ADD YOUR PASS";WiFiUDP ntpUDP;NTPClient timeClient(ntpUDP, "pool.ntp.org", 19800); // IST (UTC+5:30)

  This part connects to WiFi and sets up an NTP client to fetch time in Indian Standard Time.

  Drawing Functions

   void drawCharScaled(...) {...}void drawTextScaled(...) {...}void fillRectBuffer(...) {...}void drawRectBuffer(...) {...}

  A single character scaled by scale is drawn using the drawCharScaled function.

  A string of characters is drawn using the drawTextScaled method.

  A rectangular region in the framebuffer is filled using the fillRectBuffer function.

  A rectangular border is drawn using the drawRectBuffer function.

  Setup Function

   void setup() { pinMode(TFT_BL, OUTPUT); digitalWrite(TFT_BL, HIGH); // Turn on backlight axs15231_init(); // Initialize LCD Serial.begin(115200); WiFi.begin(ssid, password); // Connect to WiFi while(WiFi.status() != WL_CONNECTED){ delay(500); } timeClient.begin(); // Start NTP client fillRectBuffer(frameBuffer, SCREEN_W, 0, 0, SCREEN_W, SCREEN_H, BLACK); drawRectBuffer(...) // Draw 3 green rectangle borders for HH:MM:SS lcd_PushColors_rotated_90(0,0,SCREEN_W,SCREEN_H, frameBuffer); // Send framebuffer to LCD}

  This section sets up the NTP, WiFi, and display. After that, it sends the first framebuffer to the screen and draws static green rectangular boundaries for the hours, minutes, and seconds.

  Loop Function

   void loop(){ if(timeClient.update()){ // Update time from NTP int hours = timeClient.getHours(); int minutes = timeClient.getMinutes(); int seconds = timeClient.getSeconds(); ... // Only redraw digits if they have changed lcd_PushColors_rotated_90(0,0,SCREEN_W,SCREEN_H, frameBuffer); // Refresh display }}

  This part sends the new framebuffer to the display after continuously updating the time via NTP and verifying that each digit (hours, minutes, and seconds) has changed. It then only redraws the altered digits to minimize flicker.

  The main code file must be saved in a folder and the included header files, such as AXS15231B.h, pins_config.h, and AXS15231B.cpp, must be added to set up the sketch.

• 3

  BASE FRAME ASSEMBLY PROCESS

  

  

  

  

  

  

  

  • We now start the project's Body build, which starts with setting up the project's Base. We fasten the main body with the lower clamp part using M2.5 bolts.
  • The extension part is then positioned over one side of the main body, its mounting hole is aligned with the main body, and an M2 screw is used to fasten them together.
  • The nameplate, which essentially holds the main body and extension section together with four screws positioned in corners, is installed in place once the extension part has been placed.
  • Next, we add tiny magnets with a diameter of 5 mm to the main body and clamp part. Our first step is to apply a drop of super glue to the magnet's clamp mounting place. This will ensure that the magnet remains in place permanently.
  • Similar to this, we add magnets to the main body by following the same process, but we make sure to face them in the correct direction since this section employs two magnets to create a magnetic lock, and magnetism is crucial in this situation; utilizing the same poles on the same side will break the entire system.

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