Page 196 - 15 Dangerously Mad Projects for the Evil Genius

Chapter 13 ■ Levitation Machine 173

LISTING 13-1

// Project 13 - Anti-gravity
// 15 Dangerous Projects for the Evil Genius

#define coilPin 11
#define irPin 13
#define sensorPin 0

int A = 2;
// Adjust B to improve stability
int B = 60;
int C = 20;
int D = 1000;

int maxPower = 255;
long powerCountThreshold = 300000;
int objectPresent = 0;
int monitoring = false;

void setup()
{
pinMode(coilPin, OUTPUT);
pinMode(irPin, OUTPUT);
pinMode(sensorPin, INPUT);
Serial.begin(9600);
Serial.println("Ready");
Serial.println("m - toggle monitoring");
Serial.println("B - increase B");
Serial.println("b - decrease B");
}

void loop()
{
static int count = 0;
static int oldPosition = 0;
static int ambient = 0;
static long powerCount = 0;
count ++;

if (count == 1000)
{
ambient = readAmbient();
count = 0;
objectPresent = (powerCount < powerCountThreshold);
powerCount = 0;
}
int raw = 1024 - analogRead(sensorPin);
// position from top (0) of sensor region to the bottom (650)
int position = raw - ambient;
// positive value means going downwards, negative going upwards
int velocity = position - oldPosition;
int power = position / A + velocity * B + C;

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