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Viewing changes to test/receiver/pulse-freq/main.ino

  • Committer: Tim Marston
  • Date: 2012-11-28 23:18:38 UTC
  • Revision ID: tim@ed.am-20121128231838-r2t1dyawkzb6nxhe
initial commit, and a couple of receiver test programs

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test/receiver/pulse-freq/main.ino
 
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//
 
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// main.ino
 
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//
 
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// Testing reading from the receiver.  We're expecting a PWM signal, on
 
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// interrupt 0 (which is pin 2 on an Arduino Uno).
 
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//
 
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// This program tries to measure the frequency of the signal pulses in
 
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// microseconds.  It takes several measurements and prints out the average over
 
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// serial.
 
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//
 
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// number of signal pulses to average
 
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#define SIGNAL_SAMPLES 10
 
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// set to the time that the last signal pulse was at
 
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static volatile unsigned long _new_pulse_at = 0;
 
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// ISR to handle the PWM signal
 
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void signal_handler()
 
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{
 
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        // record time
 
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        _new_pulse_at = micros();
 
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}
 
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void setup()
 
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{
 
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        Serial.begin( 9600 );
 
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        // set up an interrupt handler on pin 2
 
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        attachInterrupt( 0, signal_handler, RISING );
 
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}
 
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void loop()
 
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{
 
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        unsigned long last_pulse = 0;
 
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        unsigned long intervals[ SIGNAL_SAMPLES ] = {0};
 
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        int interval_idx = 0;
 
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        while( true )
 
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        {
 
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                // detect pulse
 
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                unsigned long new_pulse = _new_pulse_at;
 
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                bool got_pulse = false;
 
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                if( new_pulse < last_pulse )
 
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                        last_pulse = new_pulse;
 
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                if( new_pulse > last_pulse )
 
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                {
 
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                        // check interval
 
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                        unsigned long interval = new_pulse - last_pulse;
 
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                        if( interval < 300 )
 
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                        {
 
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                                Serial.print( "[" );
 
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                                Serial.print( last_pulse );
 
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                                Serial.print( "," );
 
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                                Serial.print( new_pulse );
 
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                                Serial.print( "]" );
 
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                        }
 
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//                      if( interval > 19000 && interval < 20500 )
 
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//                      {
 
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                                // update interval buffer
 
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                                intervals[ interval_idx ] = interval;
 
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                                if( ++interval_idx >= SIGNAL_SAMPLES )
 
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                                        interval_idx = 0;
 
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                                got_pulse = true;
 
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//                      }
 
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                        last_pulse = new_pulse;
 
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                }
 
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                // display average?
 
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                if( interval_idx == 0 && got_pulse )
 
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                {
 
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                        // calculate average
 
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                        for( int a = 0; a < SIGNAL_SAMPLES; a++ ) {
 
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                                Serial.print( intervals[ a ] );
 
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                                if( a == SIGNAL_SAMPLES - 1 )
 
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                                        Serial.println();
 
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                                else
 
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                                        Serial.print( " " );
 
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                        }
 
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                }               
 
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        }
 
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}