It is a combination of 8 LEDs (the decimal point -DP- is the 8th), which can be arranged so that different combinations can be used to make numerical digits. Just follow the schematic circuit diagram ...

PANIC ALARM - ARDUINO // // by T.K.Hareendran // int rlyPin = 12; // Relay Output Pin int sensPin = 2; // Switch Input Pin int ledPin = 13; // LED output Pin int pzSpeaker = 10; //Piezo-speaker Output ...