implementing Tire Pressure Monitoring System PHP version

TDDMicroExercises/PHP/TirePressureMonitoringSystem/Alarm.php

@@ -0,0 +1,35 @@
+<?php
+
+class Alarm
+{
+	const LOW_PRESSURE_TRESHOLD 	= 17;
+	const HIGH_PRESSURE_TRESHOLD 	= 21;
+
+	private $sensor;
+	private $alarmOn;
+	private $alarmCount;
+
+	public function __construct() {
+		$this->sensor 		= new Sensor();
+		$this->alarmOn 		= false;
+		$this->alarmCount	= 0;		
+	}
+
+
+	public function check() 
+	{
+		$psiPressureValue = $this->sensor->popNextPressurePsiValue();
+
+		if ($psiPressureValue < Alarm::LOW_PRESSURE_TRESHOLD
+			|| Alarm::HIGH_PRESSURE_TRESHOLD < $psiPressureValue) {
+
+			$this->alarmOn = true;
+			$this->alarmCount += 1;
+		}
+	}
+
+	public function alarmOn() 
+	{
+		return $this->alarmOn;
+	}
+}

TDDMicroExercises/PHP/TirePressureMonitoringSystem/Sensor.php

@@ -0,0 +1,20 @@
+<?php
+
+
+class Sensor 
+{
+	const OFFSET = 16;
+
+	public static function SamplePressure()
+	{
+		// placeholder implementation that simulate a real sensor in a real tire
+		$pressureTelemetryValue = floor(6 * rand() * rand());
+		return $pressureTelemetryValue;
+	}
+
+	public function popNextPressurePsiValue() 
+	{
+		$pressureTelemetryValue = self::SamplePressure();
+		return self::OFFSET + $pressureTelemetryValue;
+	}
+}