source: code/branches/wiimote/src/external/wiicpp/wiic/balanceboard.c @ 10256

/*
 *      balanceboard.c
 *
 *      Written By:
 *              Gabriele Randelli       
 *              Email: < randelli (--AT--) dis [--DOT--] uniroma1 [--DOT--] it >
 *
 *      Copyright 2010
 *
 *      This file is part of wiiC.
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 3 of the License, or
 *      (at your option) any later version.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License
 *      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *      $Header$
 *
 */
#include "balanceboard.h"
#include "events.h"

/**
 *      @brief Handle the handshake data from the balance board.
 *
 *      @param bb               A pointer to a balance_board_t structure.
 *      @param data             The data read in from the device.
 *      @param len              The length of the data block, in bytes.
 *
 *      @return Returns 1 if handshake was successful, 0 if not.
 */
int balance_board_handshake(struct wiimote_t* wm, struct balance_board_t* bb, byte* data, unsigned short len) 
{
        int offset = 4;
        
        bb->cal_low_weight.top_left = 0;
        bb->cal_low_weight.top_right = 0;       
        bb->cal_low_weight.bottom_left = 0;
        bb->cal_low_weight.bottom_right = 0;
        bb->cal_medium_weight.top_left = 0;
        bb->cal_medium_weight.top_right = 0;    
        bb->cal_medium_weight.bottom_left = 0;
        bb->cal_medium_weight.bottom_right = 0;
        bb->cal_high_weight.top_left = 0;
        bb->cal_high_weight.top_right = 0;      
        bb->cal_high_weight.bottom_left = 0;
        bb->cal_high_weight.bottom_right = 0;
        bb->pressure_raw_data.top_left = 0;
        bb->pressure_raw_data.top_right = 0;    
        bb->pressure_raw_data.bottom_left = 0;
        bb->pressure_raw_data.bottom_right = 0; 
        bb->pressure_weight.top_left = 0.0;
        bb->pressure_weight.top_right = 0.0;    
        bb->pressure_weight.bottom_left = 0.0;
        bb->pressure_weight.bottom_right = 0.0; 
        bb->pressure_weight.weight = 0.0;
        
        /*
         *      Sometimes the data returned here is not correct (all bytes are 0xFF).
         *      This might happen because the wiimote is lagging
         *      behind our initialization sequence.
         *      To fix this just request the handshake again.    
         */
        if (data[offset+offset] == 0xFF && data[offset+offset+16] == 0xFF) {
                /* get the calibration data */
                byte* handshake_buf = malloc(EXP_HANDSHAKE_LEN * sizeof(byte));

                WIIC_DEBUG("Balance board handshake appears invalid, trying again.");
                wiic_read_data_cb(wm, handshake_expansion, handshake_buf, WM_EXP_MEM_CALIBR, EXP_HANDSHAKE_LEN);

                return 0;
        }
        
        bb->cal_low_weight.top_right = (data[offset+0] << 8) | data[offset+1] ;
        bb->cal_low_weight.bottom_right = (data[offset+2] << 8) | data[offset+3] ;
        bb->cal_low_weight.top_left = (data[offset+4] << 8) | data[offset+5] ;
        bb->cal_low_weight.bottom_left = (data[offset+6] << 8) | data[offset+7] ;
        bb->cal_medium_weight.top_right = (data[offset+8] << 8) | data[offset+9] ;
        bb->cal_medium_weight.bottom_right = (data[offset+10] << 8) | data[offset+11] ;
        bb->cal_medium_weight.top_left = (data[offset+12] << 8) | data[offset+13] ;
        bb->cal_medium_weight.bottom_left = (data[offset+14] << 8) | data[offset+15] ;
        bb->cal_high_weight.top_right = (data[offset+16] << 8) | data[offset+17] ;
        bb->cal_high_weight.bottom_right = (data[offset+18] << 8) | data[offset+19] ;
        bb->cal_high_weight.top_left = (data[offset+20] << 8) | data[offset+21] ;
        bb->cal_high_weight.bottom_left = (data[offset+22] << 8) | data[offset+23] ;

        /* handshake done */
        wm->exp.type = EXP_BALANCE_BOARD;

        return 1;
}

/**
 *      @brief Handle balance board event.
 *
 *      @param bb               A pointer to a balance_board_t structure.
 *      @param msg              The message specified in the event packet.
 */
void balance_board_event(struct balance_board_t* bb, byte* msg) 
{
        // Raw data
        bb->pressure_raw_data.top_right = (msg[0] << 8) | msg[1];
        bb->pressure_raw_data.bottom_right = (msg[2] << 8) | msg[3];
        bb->pressure_raw_data.top_left = (msg[4] << 8) | msg[5];
        bb->pressure_raw_data.bottom_left = (msg[6] << 8) | msg[7];
        
        /* Weight in kg (we must interpole here) */

        // Top Right
        if(bb->pressure_raw_data.top_right <= bb->cal_medium_weight.top_right) {
                bb->pressure_weight.top_right = 17.0 * (bb->pressure_raw_data.top_right - bb->cal_low_weight.top_right) / (float)(bb->cal_medium_weight.top_right - bb->cal_low_weight.top_right);
        }
        else if(bb->pressure_raw_data.top_right <= bb->cal_high_weight.top_right) {
                bb->pressure_weight.top_right = 17.0 * (bb->pressure_raw_data.top_right - bb->cal_medium_weight.top_right) / (float)(bb->cal_high_weight.top_right - bb->cal_medium_weight.top_right) + 17.0;   
        }
        else {
                bb->pressure_weight.top_right = 17.0 * (bb->pressure_raw_data.top_right - bb->cal_high_weight.top_right) / (float)(bb->cal_high_weight.top_right - bb->cal_medium_weight.top_right) + 34.0;                     
        }
        
        // Bottom Right
        if(bb->pressure_raw_data.bottom_right <= bb->cal_medium_weight.bottom_right) {
                bb->pressure_weight.bottom_right = 17.0 * (bb->pressure_raw_data.bottom_right - bb->cal_low_weight.bottom_right) / (float)(bb->cal_medium_weight.bottom_right - bb->cal_low_weight.bottom_right);
        }
        else if(bb->pressure_raw_data.bottom_right <= bb->cal_high_weight.bottom_right) {
                bb->pressure_weight.bottom_right = 17.0 * (bb->pressure_raw_data.bottom_right - bb->cal_medium_weight.bottom_right) / (float)(bb->cal_high_weight.bottom_right - bb->cal_medium_weight.bottom_right) + 17.0;    
        }
        else {
                bb->pressure_weight.bottom_right = 17.0 * (bb->pressure_raw_data.bottom_right - bb->cal_high_weight.bottom_right) / (float)(bb->cal_high_weight.bottom_right - bb->cal_medium_weight.bottom_right) + 34.0;                      
        }
        
        // Top Left
        if(bb->pressure_raw_data.top_left <= bb->cal_medium_weight.top_left) {
                bb->pressure_weight.top_left = 17.0 * (bb->pressure_raw_data.top_left - bb->cal_low_weight.top_left) / (float)(bb->cal_medium_weight.top_left - bb->cal_low_weight.top_left);
        }
        else if(bb->pressure_raw_data.top_left <= bb->cal_high_weight.top_left) {
                bb->pressure_weight.top_left = 17.0 * (bb->pressure_raw_data.top_left - bb->cal_medium_weight.top_left) / (float)(bb->cal_high_weight.top_left - bb->cal_medium_weight.top_left) + 17.0;        
        }
        else {
                bb->pressure_weight.top_left = 17.0 * (bb->pressure_raw_data.top_left - bb->cal_high_weight.top_left) / (float)(bb->cal_high_weight.top_left - bb->cal_medium_weight.top_left) + 34.0;                  
        }
        
        // Botton Left
        if(bb->pressure_raw_data.bottom_left <= bb->cal_medium_weight.bottom_left) {
                bb->pressure_weight.bottom_left = 17.0 * (bb->pressure_raw_data.bottom_left - bb->cal_low_weight.bottom_left) / (float)(bb->cal_medium_weight.bottom_left - bb->cal_low_weight.bottom_left);
        }
        else if(bb->pressure_raw_data.bottom_left <= bb->cal_high_weight.bottom_left) {
                bb->pressure_weight.bottom_left = 17.0 * (bb->pressure_raw_data.bottom_left - bb->cal_medium_weight.bottom_left) / (float)(bb->cal_high_weight.bottom_left - bb->cal_medium_weight.bottom_left) + 17.0; 
        }
        else {
                bb->pressure_weight.bottom_left = 17.0 * (bb->pressure_raw_data.bottom_left - bb->cal_high_weight.bottom_left) / (float)(bb->cal_high_weight.bottom_left - bb->cal_medium_weight.bottom_left) + 34.0;                   
        }
        
        bb->pressure_weight.weight = bb->pressure_weight.top_right + bb->pressure_weight.top_left + bb->pressure_weight.bottom_right + bb->pressure_weight.bottom_left;
}

/**
 *      @brief The balance board disconnected.
 *
 *      @param bb               A pointer to a balance_board_t structure.
 */
void balance_board_disconnected(struct balance_board_t* bb)
{
        memset(bb, 0, sizeof(struct balance_board_t));
}