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// This program tries to measure the width of the signal pulses in
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// microseconds. It takes several measurements and prints it the average over
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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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#define GRAPH_MIN 1000
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#define GRAPH_MAX 2000
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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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Serial.begin( 9600 );
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unsigned long last_pulse_off = 0;
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unsigned long intervals[ AVERAGE_SAMPLES ];
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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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for( int a = 0; a < AVERAGE_SAMPLES; a++ )
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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[ GRAPH_SIZE + 1 ] = ']';
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graph[ GRAPH_SIZE + 2 ] = 0;
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// detect pulse falling-edge
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unsigned long pulse_on = _new_pulse_on;
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unsigned long pulse_off = _new_pulse_off;
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unsigned long new_pulse_on = _new_pulse_on;
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unsigned long new_pulse_off = _new_pulse_off;
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bool got_pulse = false;
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if( pulse_off > last_pulse_off )
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if( new_pulse_off > last_pulse )
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unsigned long interval = pulse_off - pulse_on;
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if( interval > 800 && interval < 3000 )
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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 >= AVERAGE_SAMPLES )
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last_pulse_off = pulse_off;
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// update interval buffer
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intervals[ interval_idx ] = new_pulse_off - new_pulse_on;
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if( ++interval_idx >= SIGNAL_SAMPLES )
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last_pulse = new_pulse_off;
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// display average?
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( AVERAGE_DAMP || interval_idx == 0 ) )
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if( interval_idx == 0 && got_pulse )
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// calculate average
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unsigned long ave = 0;
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for( int a = 0; a < AVERAGE_SAMPLES; a++ )
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for( int a = 0; a < SIGNAL_SAMPLES; a++ )
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ave += intervals[ a ];
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ave /= AVERAGE_SAMPLES;
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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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ave /= SIGNAL_SAMPLES;
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// tell it like it is
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Serial.println( ave );
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Serial.println( round( ave ) );