LED Running Text: Single Line Scrolling Marquee

The scrolling LED marquee is one of the most commercially useful display projects — shops, restaurants, offices, and event venues use them to attract attention and convey information. A cascaded MAX7219 dot matrix display with ESP32 WiFi creates a professional scrolling text sign that can be updated from any smartphone.

Applications for Scrolling Marquee Displays

• Retail shops: Promotions, offers, new arrivals
• Restaurants: Daily specials, today’s menu
• Offices: Welcome messages, meeting room status
• Events: Schedule, announcements, sponsor messages
• Factories: Safety messages, production updates

Hardware Options: Dot Matrix vs LED Panel

• MAX7219 4-in-1 cascaded: 8-16 modules for a clear, bright single-line display. Rs.200-500 per 4 modules. Best value.
• P10 LED panel: Larger, brighter, outdoor-rated. 32×16 pixels per panel. Rs.500-1000 per panel. Best for outdoor signage.
• HUB75 panel: Full colour RGB. Rs.800-1500. Best for premium indoor displays.

Building with MAX7219 Cascaded Modules

#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#define MAX_DEVICES 8 // 8 modules = 64x8 pixels
#define CS_PIN 5
MD_Parola display = MD_Parola(MD_MAX72XX::FC16_HW, CS_PIN, MAX_DEVICES);

void setup() {
  display.begin();
  display.setIntensity(5);
  display.displayText("Welcome to Zbotic!",
    PA_CENTER, 50, 0, PA_SCROLL_LEFT);
}
void loop() {
  if (display.displayAnimate()) display.displayReset();
}

WiFi Message Update System

With ESP32, create a web interface for wireless message updates:

• Connect to the ESP32’s WiFi network from any phone
• Open the web page, type your message, hit send
• Message appears on the display within seconds
• Store multiple messages and cycle through them
• Schedule messages for specific times of day

Font Size and Readability

• Standard MAX7219 font is 5 pixels wide — readable from 3-5 metres
• For larger text, use 2 rows of modules (16 pixels high) for double-height characters
• Scroll speed: 50-100ms per pixel step is comfortable for reading
• Too slow = boring, too fast = unreadable. Let users adjust via the web interface.

Mounting for Shops and Events

• Mount at eye level (1.5-1.8m) for maximum visibility
• Above the shop entrance for passersby to see
• Use aluminium channel housing for a clean, professional look
• For temporary events, use a portable stand

Power and Longevity Considerations

• 8x MAX7219 modules at medium brightness: approximately 400 mA at 5V (2W)
• Running 24/7 costs about Rs.15-20 per month in electricity
• LED lifespan: 50,000+ hours (5+ years continuous)
• No moving parts, no bulbs to replace

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