These 7-segment displays normally require 13 pins (5 characters and 8 total segments each).<br> Solves the annoyance of using 13 pins or a bunch of chips by having an I2C constant-current matrix controller sit neatly on the back of the PCB.<br> The controller chip takes care of everything, drawing all the LEDs in the background.<br> All you have to do is write data to it using the 2-pin I2C interface.<br> There are three address select pins so you can select one of 8 addresses to control up to 8 of these on a single 2-pin I2C bus (as well as whatever other I2C chips or sensors you like).<br> The driver chip can the entire display from 1/16 brightness up to full brightness in 1/16th steps.<br> It can't individual LEDs, only the entire display at once.<br> Specification:<br> Size: Approx. 5.03 x 2.68 x 1.2 cm/2 x 1.1 x 0.5 inch<br> Package Includes:<br> 2 Pieces 0.56" 4 Digit LED Display Modules<br> Note:<br> Color might be slightly different due to the color calibration of each individual monitor.<br> Please allow slightly measuring deviation due to manual measurement.<br> These 7-segment displays normally require 13 pins (5 characters and 8 total segments each).<br> Solves the annoyance of using 13 pins or a bunch of chips by having an I2C constant-current matrix controller sit neatly on the back of the PCB.<br> The controller chip takes care of everything, drawing all the LEDs in the background.<br> All you have to do is write data to it using the 2-pin I2C interface.<br> There are three address select pins so you can select one of 8 addresses to control up to 8 of these on a single 2-pin I2C bus (as well as whatever other I2C chips or sensors you like).<br> The driver chip can the entire display from 1/16 brightness up to full brightness in 1/16th steps.<br> It can't individual LEDs, only the entire display at once.<br> Specification:<br> Size: Approx. 5.03 x 2.68 x 1.2 cm/2 x 1.1 x 0.5 inch<br> Package Includes:<br> 2 Pieces 0.56" 4 Digit LED Display Modules<br> Note:<br> Color might be slightly different due to the color calibration of each individual monitor.<br> Please allow slightly measuring deviation due to manual measurement.<br> Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-DIMEANI official store