Serial 7-segment LED display module (4 digits)

This serial LED display module allows you to interface a 4-digit 7-segment LED display with only three I/O pins of a microcontroller, and gives you full control of all digits and decimal points.

4-digit serial seven segment LED display


  • based on MAX7219 display driver
  • SPI interface (3 pins)
  • operates at +5V supply
  • individual control of all digits and decimal points
  • display brightness control through software
  • dimensions 1.95″ x 1.4″ (50mm x 36mm)
  • 0.56″ LED display

Here’s an example that shows how to interface this display module with PIC microcontrollers.

Assembling the board

The kit consists of:
  • printed circuit board (1)
  • MAX7219 (1)
  • 0.56″ four-digit seven segment LED display (1)
  • 1N4148 diode (1)
  • 18K resistor (1)
  • 100nF capacitor (1)
  • 5-pin straight male header

Serial 7-segment LED display kit

The following pictures describes the assembling procedure.

Step 1: Hold the PCB with soldering helping hands

Step 2: Next solder low profile components such as the capacitor, diode and resistor, as shown above

Step 3: Next solder the MAX7219 chip

Step 4: Place the LED display on the top of MAX7219 and solder its pins

Step 5: Finally, solder the connecting header pins

Revision 1 (12/15/2012)

The PCB has slightly been revised recently. Everything remains the same except there are two header connectors available now. One for interfacing the display with a microcontroller and other for cascading multiple displays. New PCB is shown below.

Revised PCB (Rev. 1)

Revision 2 (2/20/2013)

This has been revised second time and the new board will have following features:

  • High quality 0.40″ display (LTC-4727JS) with bright yellow light emitting diodes
  • Four digits, decimal and colon segments
  • Round PCB corners 

Rev. 2: Four digit SPI seven segment LED display

Price: $11.50 for kit, and $14.50 for assembled board. The payment will be through Paypal. If you want the kit or the assembled board, email me first at admin (at), and I will send you my Paypal information. Or you can also buy it directly on Tindie.