Int COUNT=0 //count integer for 0-9 increment #define segG 8// connecting segment G to PIN8 #define segF 7// connecting segment F to PIN7 #define segE 6// connecting segment E to PIN6 #define segD 5// connecting segment D to PIN5 #define segC 4// connecting segment C to PIN4 #define segB 3// connecting segment B to PIN3 #define segA 2//connecting segment A to PIN2

Here we are going to write a program turning each segment ON and OFF for a count 0-9. The working of 0-9 counter is best explained step by step in C code given below: With both the pins high we get “1” on display. So as seen above we are going to power pins corresponding to the digit that to be shown on display. We need to power segments “B, C”, for segment B, C to turn ON we need to power PIN1, PIN2. So every time we need a “0”, we need to power all the pins mentioned. We need to turn the LEDs of segments “A, B, C, D, E F”, so we need to power PIN0, PIN1, PIN2, PIN3, PIN4 and PIN5. Now, if we want to display a “0” in this display as shown in below figure. For avoiding this a common resistor can be provider at common terminal, as shown in circuit diagram. Each segment should not be power with a voltage greater than 4v, if did the display will be damaged permanently. One can check each segment of display by using multimeter in diode mode. Here the common ground has to be connected to ground for the display to work.

And is common ground type as shown in figure.

Now to understand the working, consider a seven segment display is connected to a port, so say we have connected “A segment of display to PIN0”, “B segment of display to PIN1”, “A segment of display to PIN3”, “A segment of display to PIN4”, “A segment of display to PIN5”, “A segment of display to PIN6”. PIN3 or PIN8 or CC to ground through 100Ω resistor. PIN5 or H or DP to PIN 9 ///not needed as we are not using decimal point The connections which are done for 7 segment display are given below: Hardware: ARDUINO UNO, power supply (5v), HDSP5503 seven segment display (two pieces) (any common cathode will do ), 47uF capacitor (connected across power supply). These CC and CA come in very handy while multiplexing several cells together. In CA the positive of every LED is connected together and brought out as VCC. The circuit connection of LEDs in common cathode and common anode is shown in above figure. Here one can observe that, in CC the negative terminals of every LED is connected together and brought out as GND.

Seven segment display arduino code