sci-oly-detector-building

[RADIOACTIVE] arduino thermometer for science olympiad
git clone git://git.figbert.com/sci-oly-detector-building.git
Log | Files | Refs | LICENSE

Operational.ino (2208B)

      1 #include <hd44780.h>
      2 #include <Wire.h>
      3 #include <hd44780ioClass/hd44780_I2Cexp.h>
      4 hd44780_I2Cexp lcd;
      5 #define THERMISTORNOMINAL 100000
      6 #define TEMPERATURENOMINAL 25
      7 #define NUMSAMPLES 2
      8 #define BCOEFFICIENT 4000
      9 #define SERIESRESISTOR 100000
     10 
     11 int red_light_pin= 12;
     12 int green_light_pin = 10;
     13 int blue_light_pin = 11;
     14 int samples[NUMSAMPLES];
     15 
     16 void setup() {
     17     lcd.begin(16, 2);
     18     lcd.backlight();
     19     Serial.begin(9600);
     20     analogReference(EXTERNAL);
     21     pinMode(red_light_pin, OUTPUT);
     22     pinMode(green_light_pin, OUTPUT);
     23     pinMode(blue_light_pin, OUTPUT);
     24 }
     25 
     26 void loop() {
     27     float first = voltage(0), second = voltage(1);
     28     float bridge = (first + second) / 2;
     29     float volts = bridge * (3.3 / 1023.0);
     30     float res = resistance(bridge);
     31     float temp = celsius(res);
     32     lcd.setCursor(5, 0);
     33     lcd.print(String(temp) + "C");
     34     lcd.setCursor(5, 1);
     35     lcd.print(String(volts) + "V");
     36     if (temp < 0.0) {
     37       digitalWrite(blue_light_pin, LOW);
     38       digitalWrite(green_light_pin, LOW);
     39       digitalWrite(red_light_pin, LOW);
     40     } else if (temp < 21.0) {
     41       digitalWrite(blue_light_pin, HIGH);
     42       digitalWrite(green_light_pin, LOW);
     43       digitalWrite(red_light_pin, LOW);
     44     } else if (temp < 52.0) {
     45       digitalWrite(blue_light_pin, LOW);
     46       digitalWrite(green_light_pin, HIGH);
     47       digitalWrite(red_light_pin, LOW);
     48     } else if (temp <= 75.0) {
     49       digitalWrite(blue_light_pin, LOW);
     50       digitalWrite(green_light_pin, LOW);
     51       digitalWrite(red_light_pin, HIGH);
     52     }
     53     delay(1000);
     54     lcd.clear();
     55 }
     56 
     57 float voltage(int pin) {
     58     uint8_t i;
     59     float volt;
     60     for (i=0; i< NUMSAMPLES; i++) {
     61      samples[i] = analogRead(pin);
     62      delay(10);
     63     }
     64     volt = 0;
     65     for (i=0; i< NUMSAMPLES; i++) {
     66        volt += samples[i];
     67     }
     68     volt /= NUMSAMPLES;
     69     return volt;
     70 }
     71 
     72 float resistance(float volts) {
     73     volts = 1023 / volts - 1;
     74     volts = SERIESRESISTOR / volts;
     75     return volts;
     76 }
     77 
     78 float celsius(float res) {
     79     float celsius = res / THERMISTORNOMINAL;
     80     celsius = log(celsius);
     81     celsius /= BCOEFFICIENT;
     82     celsius += 1.0 / (TEMPERATURENOMINAL + 273.15);
     83     celsius = 1.0 / celsius;
     84     celsius -= 273.15;
     85     return celsius;
     86 }