/elec/quadcopter

//

// main.ino

//

// This software is intended to be run on a small Arduino (e.g., a Pro Mini),

// whose purpose is dedicated to talking to the RC system.  That is to say, it

// listens to the PPM signal from the RC receiver and produces a compatible

// single for the ESCs to control the motors.  It additionally talks to the main

// board via a trivial serial protocol.  In so doing, this software relieves the

// main board (and software running on it) of the task of interfacing with any

// of the RC system.

//

// The 8 channels (from the RC receiver) need to be combined and fed to two

// interrupts on the Arduino.  They need to be combined in such a way as to

// alternate pulses between the two interrupts (which are alternately used to

// read the pulses).  Like this:

//

//                  ch1  ch3  ch5  ch7  ch2  ch4  ch6  ch8

//                   |    |    |    |    |    |    |    |

//                   ▼    ▼    ▼    ▼    ▼    ▼    ▼    ▼

//                   ¯    ¯    ¯    ¯    ¯    ¯    ¯    ¯

//            ___    |    |    |    |    |    |    |    |     ___

//    GND ---|___|---+----+----+----+    +----+----+----+----|___|--- GND

//             R                    |    |                     R

//             ____________________ | __ | _____________________

//                                  |    |

//                           pin 2  o    o  pin 3

//                    (interrupt 0)        (interrupt 1)

//

// The two resistors in the circuit are pull-down resistors (so, say 100kΩ).

// Without them, the Arduino is unable to read the pulse wave at all.

//

// Note that your receiver may not send pulses sequentially, in "channel order".

// If this turns out to be the case, you will need to arrange for the pulses to

// wire up the channels in an order whereby the pulses alternatively alternately

// between the two interrupts and adjust the channel order below.

#include "config.h"

#include "receiver.h"

// the width of the display of a single channel (in chars)

#define GRAPH_SIZE 7

// the channel's expected range for use in drawing (should be similar to

// {MAX,MIN}_PULSE_WIDTH values)

#define GRAPH_MIN 1000

#define GRAPH_MAX 2000

void setup()

{

	Receiver::setup();

	Serial.begin( 9600 );

}

void draw_graph( unsigned long channel_values[] )

{

	// init graph

	static char graph[ GRAPH_SIZE + 2 ];

	static char inited_graph = false;

	if( !inited_graph ) {

		for( int a = 1; a < GRAPH_SIZE + 1; a++ )

			graph[ a ] = '_';

		graph[ 0 ] = '|';

		graph[ GRAPH_SIZE + 1 ] = 0;

		inited_graph = true;

	}

	// draw channels

	for( int a = 0; a < NUM_CHANNELS; a++ ) {

		unsigned long value = max( 0,

			min( channel_values[ a ], GRAPH_MAX ) - GRAPH_MIN );

		int pos = ( GRAPH_SIZE ) * value / ( GRAPH_MAX - GRAPH_MIN );

		graph[ pos + 1 ] = '^';

		Serial.print( graph );

		graph[ pos + 1 ] = '_';

	}

	Serial.println( "|" );

}

void loop()

{

	unsigned long channel_values[ NUM_CHANNELS ];

	while( true )

	{

		if( Receiver::read_channels( channel_values ) )

			draw_graph( channel_values );

	}

}