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

  • Committer: Tim Marston
  • Date: 2013-10-30 22:41:50 UTC
  • Revision ID: tim@ed.am-20131030224150-t6xs1l783m2yg6rd
updated comments in receiver test programs

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test/receiver/pulse-width/main.ino
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// microseconds.  It takes several measurements and prints it the average over
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// serial.
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//
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// number of signal pulses to average (for damping)
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#define DAMPING_SAMPLES 1
 
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// NOTES: Due to the way our receiver works (by varying the position of the
 
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// rising edge of the pulse and keeping the falling edge fixed), it is
 
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// sufficient for us to measure the pule width to determine the channel value
 
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// (e.g., throttle position).  But it should be noted that this relies on a
 
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// quirk of our receiver/transmitter and it is not truly measuring PPM.  Our
 
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// next experiment is measuring PPM (../ppm-read).
 
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// number of signal pulses to average
 
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#define AVERAGE_SAMPLES 1
 
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// should average be result, or damping?
 
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#define AVERAGE_DAMP 1
 
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// graphic display
 
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#define GRAPH 1
 
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#define GRAPH_MIN 1000
 
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#define GRAPH_MAX 2000
 
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#define GRAPH_SIZE 30
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// set to the time that the last signal pulse was at
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        Serial.begin( 9600 );
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}
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void loop()
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{
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        unsigned long last_pulse_off = 0;
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        unsigned long intervals[ DAMPING_SAMPLES ] = {0};
 
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        unsigned long intervals[ AVERAGE_SAMPLES ];     
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        int interval_idx = 0;
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        // reset intervals
 
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        for( int a = 0; a < AVERAGE_SAMPLES; a++ )
 
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                intervals[ a ] = 0;
 
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#ifdef GRAPH
 
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        // init graph
 
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        char graph[ GRAPH_SIZE + 3 ];
 
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        for( int a = 1; a < GRAPH_SIZE + 1; a++ )
 
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                graph[ a ] = '-';
 
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        graph[ 0 ] = '[';
 
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        graph[ GRAPH_SIZE + 1 ] = ']';
 
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        graph[ GRAPH_SIZE + 2 ] = 0;
 
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#endif // GRAPH
 
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        while( true )
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        {
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                // detect pulse falling-edge
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                        {
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                                // update interval buffer
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                                intervals[ interval_idx ] = pulse_off - pulse_on;
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                                if( ++interval_idx >= DAMPING_SAMPLES )
 
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                                if( ++interval_idx >= AVERAGE_SAMPLES )
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                                        interval_idx = 0;
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                                got_pulse = true;
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                }
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                // display average?
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                if( got_pulse )
 
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                if( got_pulse &&
 
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                        ( AVERAGE_DAMP || interval_idx == 0 ) )
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                {
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                        // calculate average
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                        unsigned long ave = 0;
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                        for( int a = 0; a < DAMPING_SAMPLES; a++ )
 
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                        for( int a = 0; a < AVERAGE_SAMPLES; a++ )
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                                ave += intervals[ a ];
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                        ave /= DAMPING_SAMPLES;
 
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                        ave /= AVERAGE_SAMPLES;
 
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#ifdef GRAPH
 
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                        // draw graph
 
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                        int pos = ( GRAPH_SIZE ) *
 
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                                ( ave - GRAPH_MIN ) / ( GRAPH_MAX - GRAPH_MIN );
 
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                        graph[ pos + 1 ] = '|';
 
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                        Serial.println( graph );
 
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                        graph[ pos + 1 ] = '-';
 
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#else // GRAPH
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                        // tell it like it is
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                        Serial.print( ave );
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                        Serial.print( "\r\n" );
 
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                        Serial.println( ave );
 
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#endif // GRAPH
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                }               
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        }
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}