var SpeedMeter = function(pin, levelUpPin, levelDownPin, weighting, pulsesPerRev, timeOut, bounceTime)
{
var rpm = 0;
var level = 1;
var timeAct = 0;
var timeOld = 0;
var timeDiff = 0;
var timeLevel = 0;
var watchdog = null;
var gpio = require('rpi-gpio');
var power = [
[6,12,20,29,40,53,69,79,92,106,121],
[8,16,26,38,53,68,88,103,120,138,152],
[9,20,32,47,66,84,107,125,148,172,186],
[11,23,39,56,79,101,126,150,173,206,219],
[13,27,45,65,92,117,145,175,202,238,254],
[15,31,52,75,105,135,166,202,231,275,289],
[16,35,58,85,118,152,185,226,260,305,332],
[18,39,65,96,131,169,208,249,289,333,375],
[19,42,71,104,144,184,227,272,318,361,408],
[21,46,77,113,157,199,245,295,345,386,442],
[23,50,84,123,170,216,262,318,372,413,480],
[24,53,89,131,183,230,279,342,398,441,512],
[26,56,94,139,196,245,296,365,424,468,548],
[28,60,101,148,209,261,318,389,449,494,585],
[30,64,108,158,222,277,337,415,476,518,620],
[32,68,115,168,235,296,355,439,503,548,658],
[33,72,122,177,248,312,373,463,530,576,694],
[35,76,129,187,261,328,390,484,556,606,727],
[37,79,134,195,274,342,407,507,572,632,763],
[39,83,140,204,287,354,424,528,598,659,790],
[40,87,146,213,300,368,442,551,616,689,812],
[42,91,153,223,313,385,461,574,645,720,840],
[44,95,160,234,326,401,479,598,673,752,872],
[47,101,171,246,340,418,501,625,706,788,908]
];
weighting = weighting || 0;
pulsesPerRev = pulsesPerRev || 1;
timeOut = timeOut || 10000;
bounceTime = bounceTime || 200;
gpio.on('change', function(channel, value)
{
if (channel == pin)
{
var timeAct = new Date();
if ((timeAct - timeOld) > bounceTime)
{
if (watchdog)
{
clearTimeout(watchdog);
}
if (timeOld)
{
timeDiff *= weighting;
timeDiff += (1 - weighting) * (timeAct - timeOld);
rpm = 60000 / (timeDiff * pulsesPerRev);
}
timeOld = timeAct;
watchdog = setTimeout(function()
{
timeOld = 0;
rpm = 0;
}, timeOut);
}
}
else if (channel == levelUpPin)
{
var timeLevelUp = new Date();
if ((timeLevelUp - timeLevel) > bounceTime)
{
if (level < 23)
{
++level;
}
timeLevel = timeLevelUp;
}
}
else if (channel == levelDownPin)
{
var timeLevelDown = new Date();
if ((timeLevelDown - timeLevel) > bounceTime)
{
if (level > 1)
{
--level;
}
timeLevel = timeLevelDown;
}
}
});
gpio.setup(pin, gpio.DIR_IN, gpio.EDGE_RISING);
gpio.setup(levelUpPin, gpio.DIR_IN, gpio.EDGE_RISING);
gpio.setup(levelDownPin, gpio.DIR_IN, gpio.EDGE_RISING);
//gpio.setup(levelUpPin, gpio.DIR_IN, gpio.EDGE_FALLING);
//gpio.setup(levelDownPin, gpio.DIR_IN, gpio.EDGE_FALLING);
this.getSpeed = function()
{
return rpm;
};
this.getLevel = function()
{
return level;
};
this.getPower = function()
{
var lowerVal = 0;
var upperVal = 0;
var idxLower = Math.floor(rpm / 10);
var idxUpper = Math.ceil(rpm / 10);
if (idxLower > 1)
{
lowerVal = power[level - 1][idxLower - 2];
}
else
{
idxLower = 0;
}
if (idxUpper > 1 && idxUpper <= 12)
{
upperVal = power[level - 1][idxUpper - 2];
}
else if (idxUpper > 12)
{
console.log("RPM(", rpm, ") out of range");
return power[level - 1][10];
}
else if (idxUpper <= 1)
{
idxUpper = 0;
}
if (idxUpper == 0 && idxLower == 0)
{
return 0;
}
return (upperVal - lowerVal) / (idxUpper * 10 - idxLower * 10) * (rpm - idxLower * 10) + lowerVal;
};
};
module.exports.SpeedMeter = SpeedMeter;
