Simple Stick User Guide - Building a 3-Bit Binary Counter

Simple Stick User Guide - Building a 3-Bit Binary Counter

Ensure you have gone through our Simple Stick Overview Page before you go ahead with the Programming Tutorials.

A Binary Counter is an interesting project for the beginner to get started right after blinking an LED. A Binary counter is a simple counter that displays the current counter value in binary format. we have 3 On-board LEDs connected to Pins 5,10 &13 on the Simple Stick, we can use these to build a 3-bit binary counter that will automati cally increment every second and reset once it reaches 7.

We can assume the LED connected to PIN 13 to be the LSB [Least Significant Bit] and the LED connected to PIN 5 as the MSB [Most Significant Bit] . We can have a counter variable that we can increment till 7 and reset to 0 on reaching 7.

Now Lets take a look at the logic

Heres how a Binary counter will work
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
0 0 0
...... and on

If you notice, the LSB is toggling every cycle, the Middle Bit is toggling every 2 cycles and the MSB is toggling every cycle, To achieve this effect, we can use the MOD operator (%)

Counter % 2 will produce an alternating output of '1' & '0' that changes every cycle

(Counter/2) % 2 will produce an alternating output of '1' & '0' that changes every 2 cycles(whatever you divide by!)

(Counter/4) % 2 will produce an alternating output of '1' & '0' that changes every 4 cycles

Heres a Demo Video of the same

Heres the code for this... 
Binary_Counter.ino

 /*   
 This sketch automatically increases a 3 bit number every second  
 and shows the output on 3 LEDs   
 */  
 void setup()  
 {  
  pinMode(5,OUTPUT);   // declare LED pins as output pins  
  pinMode(10,OUTPUT);  
  pinMode(13,OUTPUT);  
 }  
 void loop()  
 {  
  for(int i=0;i<8;i++)  // increment automatically from 0 to 7  
  {  
   int a=i%2;      // calculate LSB   
   int b=i/2 %2;     // calculate middle bit  
   int c=i/4 %2;     // calculate MSB   
   digitalWrite(5,c);  // write MSB  
   digitalWrite(10,b);  // write middle bit  
   digitalWrite(13,a);  // write LSB  
   delay(1000);     // wait for a second  
  }  
 }  

Enjoy... and feel free to drop us an email with questions you might have -> info@simplelabs.co.in