buy hot The Fixer cool video Year One download Kasabian album nice Terminator Salvation hit cool track Jordin Sparks USA Whatever Works video download Check My Brain melodies nice video Finding Nemo nice Pop - Various Artists hit cheap DIVX Year One

digital-diy.com

Swordfish Tutorial - ADC (Control LED Blink Speed) Print E-mail
( 2 Votes )
  
Saturday, 04 April 2009 08:22

This tutorial/example covers another quick guide on how to use Analogue to Digital conversions with a PIC micro. It's achieved by interfacing with a 1K potentiometer to determine how fast the LED will blink. Some other aspects covered in this example include the use of the 18F4550 with the internal oscillator and basic function use.

 

LED20Blink20via20ADC1

Simulation video of circuit

 

Basically the PIC micro will sample AN0 (PORTA.0) and get a reading from 0 to 1023 (0V to 5V). From there, I use the DelaymS command to alter the time that the LED is on and off for. Its very basic, but does cover a couple of underlying features such as the use of a function;

 

Device = 18F2550                    // Setup the device/clock information
Clock = 8
Config FOSC = INTOSCIO_EC
 
Include "ADC.bas"                   // Include the ADC.bas library
 
Dim LED as PORTC.0                  // Declare the LED pin
 
 
function Get_ADC_Sample() as word   // Function to grab the ADC sample
 
   result = ADC.Read(0)             // Grab an ADC sample from channel 0
   result = result * 2              // Scale the answer up by a factor of 2
 
end function
 
 
OSCCON = %01110110                 // Setup the internal OSC for 8Mhz
 
Input(PORTA.0)                     // Make AN0 an input
 
While True                         // Create an infinate loop
 
    High(LED)                      // Make the LED pin High
    Delayms(100 + Get_ADC_Sample)  // Delay for 0.1 seconds + the ADC result
 
    Low(LED)                       // Make the LED pin Low
    Delayms(100 + Get_ADC_Sample)  // Delay for 0.1 seconds + the ADC result
 
Wend 

 


Simulation;

 

Comments (2)
  • MrDEB  - nice demo of ADC

    I plan to build a Therminine?? (musical instrument using photo transistors)
    using this ADC several resistors instead of cDS (tooo slow to respond)in an array thus making numerious voltage dividers.
    saw similar on HACK A DAY site

  • digital-diy

    I think I've seen something similar too - it could play music from images printed on paper

Write comment
Your Contact Details:
Comment:
[b] [i] [u] [url] [quote] [code] [img]   
Security
Please input the anti-spam code that you can read in the image.
Last Updated ( Tuesday, 13 October 2009 09:32 )