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@pReya pReya/tempAlarm.c
Created Oct 30, 2016

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Arduino Temperature Alarm and bar LED script
#include <math.h>
float tempRaw, tempAvg;
uint8_t tempPin = 7;
uint8_t speakerPin = 2;
uint8_t barLedPins[] = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 };
uint8_t barLedPinsLength = sizeof(barLedPins) / sizeof(barLedPins[0]);
uint8_t lowTempLimit = 24;
uint8_t highTempLimit = 36;
uint8_t tempDisplayRange = highTempLimit - lowTempLimit;
float tempDiffPerLed = tempDisplayRange / barLedPinsLength;
float tempArray[10];
uint8_t tempArrayLength = sizeof(tempArray) / sizeof(tempArray[0]);
uint8_t noOfLedsToActivate;
uint8_t wPos = 0;
void setup()
{
analogReference(INTERNAL);
printSerialDebug();
// Initialize tempreature average array with nil values
for (uint8_t i =0; i < tempArrayLength; i++)
{
tempArray[i] = -300.0;
}
// Set Output mode for LEDs
for (uint8_t i = 0; i < barLedPinsLength; i++)
{
pinMode(barLedPins[i], OUTPUT);
}
}
void loop()
{
// Get new measurement
tempRaw = analogRead(tempPin) / 9.31;
tempAvg = pushNewValueAndGetAverage(tempArray, tempRaw, tempArrayLength);
noOfLedsToActivate = (uint8_t) (roundf(tempAvg - lowTempLimit) / tempDiffPerLed);
Serial.print("Raw: ");
Serial.print(tempRaw);
Serial.print(" -- Avg: ");
Serial.print(tempAvg);
Serial.print(" -- LEDs: ");
Serial.print(noOfLedsToActivate);
Serial.print("\n");
// Activate bar LEDs
digitalWrite(barLedPins[noOfLedsToActivate], HIGH);
if (tempAvg > highTempLimit)
{
analogWrite(speakerPin,500);
delay(1000);
analogWrite(speakerPin,0);
}
delay(100);
digitalWrite(barLedPins[noOfLedsToActivate], LOW);
}
void printSerialDebug()
{
Serial.begin(9600);
Serial.print("High Temp: ");
Serial.print(highTempLimit);
Serial.print(" -- Low Temp: ");
Serial.print(lowTempLimit);
Serial.print(" -- Diff: ");
Serial.print(tempDisplayRange);
Serial.print(" -- Diff per LED: ");
Serial.print(tempDiffPerLed);
Serial.print("\n");
}
float pushNewValueAndGetAverage(float *array, float newVal, uint8_t arrSize)
{
// Insert new value
array[wPos] = newVal;
// Increment next writing position with wraparound
wPos = (wPos+1) % arrSize;
float sum = 0.0;
uint8_t validValues = 0;
// Calculate average value
for (uint8_t i = 0; i < arrSize; i++)
{
if (array[i] != -300.0)
{
validValues++;
sum = sum + array[i];
}
}
return sum/validValues;
}
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