Arduino and Seven Segment

This is to give a small idea of controlling many seven segments using only one Arduino-UNO.

Simply put.... The basic idea is usage of "Transistor Switching".
SSDs==Seven Segment Displays


Steps:
1. Get one Arduino and the required number of SSDs, for controlling n SSDs one needs (7+n) arduino pins, So for arduino uno max. limit of SSDs that can be controlled will be 5.
But its preferable to use only three of them.
2. I used Common Cathode one.
3. Connect all the display signal pins (all pins except the 3 and 8 i.e. ground pins) of all the three SSDs together accordingly and interconnect them to the Arduino ports 2-8.
(interconnect together means the first pin of all the 3 SSDs are connected togther/ parallely connected to pin 2 of Arduino and so on....)
4. The Ground pins from each SSDs is selected (one from 3 or 8) and is connected to the Collector of Transistor (preferably BC548, as i used that one and it worked perfectly), base is connected to the Arduino pins 9-11 via a 1K resistor, and emitter is grounded.
5. The program is written in such a way that each number that has to be feeded to each SSD is simultaneously changed while changing the trigger in pins 9, 10 & 11.
6. With continuous switching between HIGH and LOW..... Any 3 digit number can be represented in the displays (from 999-000).


If you need Arduino code, Contact me via email.