Arduino - Binary Counter

Binary Counter

Introduction

• For part four of my arduino tutorial we will be building a binary counter.
• Binary is a way of representing numbers using base powers of 2.
  • each number in binary is represented by a series of 1 and 0.
  • each 1 or 0 represents a power of two.
    • starting at the rightmost digit, this is 2^0. the digits immediatly to the left is 2^1, then the next digit is 2^2, etc.
    • to convert to base 10, simply add up all the powers of 2 for which there is a 1 in the binary number.
  • for example, the binary number 0101 in base 10 is 5.
    • the 1 at the right most digit repesents 2^0
    • the digit to the left is 0, so it is skipped over.
    • the digit to the left of the first 0 is a 1 which represents 2^2
    • finally, the left most digit is a 0, so it is skipped.
    • so the final number is 2^0 + 2^2 which equals 5
• for more information on binary numbers, please see wikipedia

Parts needed

• for this project, you will need the following parts:
  • Arduino
  • BreadBoard
  • (four) LED
  • (four) 220 ohm resistors
  • (one) push button
  • (one) 2k ohm resistor
  • wires

Circuit

here is the circuit diagram for the Binary Counter

• things to note:
  • each LED is connected to its own 220 ohm resistor to ground
  • each LED is connected to its own seperate pin on the arduino
  • the push button has a pull down resistor connected to ground.

here is the circuit i built for this project.

Code

here is the code for this project. the complete code can be found here

• the new parts of the code for this project are:
  • counter++
    • the ++ on the end of counter is a post fix increment
    • this is simply a short hand way to update the value of counter by 1.
  • if(counter & 0b01)
    • this code is checking if the binary number for counter has a 1 in the 2^0 place. if so, it executes the code in brackets.
    • & is the bitwise AND operator
    • for information on bitwise AND, please check wikipedia
    • 0b01
      • 0b indicates a binary number. everything after the b is intepreted as a binary number
        • in this case, 0b01 is binary 1
  • delay(150)
    • delay isnt new, but debouncing is.
      • debouncing is a way to prevent the arduino from reading multiple button presses which happen in quick succession.
        • it is quite easy to get multiple quick buton presses when you just intended to press it once. this is a characteristic of buttons and relays

Results, Conclusions, and Final Remarks

• If all went well, your circuit should count up with each button press.you should see the LEDs count up in binary.
  • since we only have four LEDs the highest number we can count to is 15.
  • when count reaches 16 and higher, we have a situation known as overflow.

going further

further things to do with this project.

• you can add more LEDs to count to an even higher number
• using what you've learned about if statments, can you make counter reset back to 0 after it reaches 16?
• try making it count backwards. start at 15 and go down to zero, decreasing counter by 1 with each button press.
  • hint: you might want to replace the postfix increment ++ with the postfix decrement --
• once you've got it working correctly, try removing the delay(150). you will see first hand how debouncing improves the performance of this circuit.
• try having it count up/down only using code, try eliminating the button altogether.

thank you for checking out my tutorial. check back soon for the next part of this tutorial.