Create Detector_Building.ino

1 files changed, 168 insertions, 0 deletions

diff --git a/Detector_Building/Detector_Building.ino b/Detector_Building/Detector_Building.ino
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+/*
+ * Detector Building
+ * Code by Anthony Wang
+ * Ladue High School Science Olympiad
+ */
+
+
+/*
+ * TODO:
+ * BUG FIXING: Expect bugs!
+ */
+
+
+// Constants
+const int LED_R = 4, LED_G = 3, LED_B = 2, THERM = 0; // Device component pins
+const double R_k = 10000, V_in = 5, analog_max = 1023; // Device constants
+
+
+// Temperature conversions
+inline double f2c(double f) { return (f - 32) * 5 / 9; } // Fahrenheit to Celsius
+inline double c2f(double c) { return c * 9 / 5 + 32; } // Celsius to Fahrenheit
+inline double k2c(double k) { return k - 273.15; } // Kelvin to Celsius
+inline double c2k(double c) { return c + 273.15; } // Celsius to Kelvin
+inline double f2k(double f) { return c2k(f2c(f)); } // Fahrenheit to Kelvin
+inline double k2f(double k) { return c2f(k2c(k)); } // Kelvin to Fahrenheit
+
+
+// Analog to digital conversion
+inline double a2d(int a) { return V_in * a / analog_max; }
+inline int d2a(double d) { return d * analog_max / V_in; }
+
+  
+// Utility functions
+// No C++ standard library :(
+void sort(int& a[], int n) {
+  // Bubble sort
+  // Slow but n < 30 so OK
+  // Too lazy to implement a fast sort
+  for (int i = 0; i < n; i++) {
+    for (int j = 0; j < n - 1; j++) {
+      if (a[j] > a[j + 1]) {
+        int tmp = a[j];
+        a[j] = a[j + 1];
+        a[j + 1] = tmp;
+      }
+    }
+  }
+}
+
+
+// Calibration data
+const int n = 3, m = n / 3; // Number of data points, MUST be multiple of 3
+double V[n] = { 2.5, 3.26, 3.96 }; // Voltage measurements
+double T[n] = { 25, 39.15, 60 }; // Temperature measurements
+double V_mid[m]; // Stores each piecewise segment for binary search
+double A[m], B[m], C[m]; // Coefficients for each piecewise component
+
+
+// Calculations
+// Steinhart-hart stuff
+void calculate() {
+  sort(V, n);
+  sort(T, n);
+  double R[n], L[n], Y[n], G[n];
+  for (int i = 0; i < n; i++) R[i] = R_k * (V_in / V[i] - 1);
+  for (int i = 0; i < n; i++) L[i] = log(R[i]);
+  for (int i = 0; i < n; i++) Y[i] = 1 / c2k(T[i]);
+  for (int i = 0; i < n; i += 3) {
+    G[i + 1] = (Y[i + 1] - Y[i]) / (L[i + 1] - L[i]);
+    G[i + 2] = (Y[i + 2] - Y[i]) / (L[i + 2] - L[i]);
+  }
+  for (int i = 0; i < n; i += 3) { // Don't ask how this works
+    C[i / 3] = (G[i + 2] - G[i + 1]) / (L[i + 2] - L[i + 1]) / (L[i] + L[i + 1] + L[i + 2]);
+    B[i / 3] = G[i + 1] - C[i / 3] * (L[i] * L[i] + L[i] * L[i + 1] + L[i + 1] * L[i + 1]);
+    A[i / 3] = Y[i] - L[i] * (B[i / 3] + L[i] * L[i] * C[i / 3]);
+  }
+  for (int i = 0; i < n; i += 3) V_mid[i / 3] = (i ? (V[i - 1] + V[i]) / 2 : V[i]);
+}
+
+
+// Arduino stuff
+void blink(int pin) {
+  digitalWrite(pin, HIGH);
+  delay(1000);
+  digitalWrite(pin, LOW);  
+}
+void setup() {
+  Serial.begin(9600);
+  pinMode(LED_R, OUTPUT);
+  pinMode(LED_G, OUTPUT);
+  pinMode(LED_B, OUTPUT);
+
+  // blink(LED_R);
+  // blink(LED_G);
+  // blink(LED_B);
+
+  // Debug stuff
+  /*for (int i = 0; i < m; i++) {
+    Serial.print("Segment lower bound: ");
+    Serial.print(i ? V_mid[i - 1] : 0);
+    Serial.print(" Segment upper bound: ");
+    Serial.print(V_mid[i]);
+    Serial.print(" A: ");
+    Serial.print(A[i], 12);
+    Serial.print(" B: ");
+    Serial.print(B[i], 12);
+    Serial.print(" C: ");
+    Serial.print(C[i], 12);
+    Serial.println();
+  }*/
+}
+
+
+// Main loop
+void loop() {
+  int V_raw = analogRead(THERM); // Read in raw analog value
+  double V_out = a2d(V_raw); // Convert analog to digital
+  double R_t = R_k * (V_in / V_out - 1); // Thermistor resistance
+
+  int s = 0;
+  while (s < m && V_out > V_mid[s + 1]) s++; // Find correct segment
+  
+  double logR_t = log(R_t);
+  double K = 1.0 / (A[s] + B[s] * logR_t + C[s] * logR_t * logR_t * logR_t); // Steinhart-hart
+  double C = k2c(K);
+  double F = c2f(C);
+
+  // LED stuff
+  if (C <= 25) {
+    digitalWrite(LED_R, LOW);
+    digitalWrite(LED_G, LOW);
+    digitalWrite(LED_B, HIGH);
+  }
+  else if (C <= 50) {
+    digitalWrite(LED_R, LOW);
+    digitalWrite(LED_G, HIGH);
+    digitalWrite(LED_B, LOW);
+  }
+  else if (C <= 75) {
+    digitalWrite(LED_R, HIGH);
+    digitalWrite(LED_G, LOW);
+    digitalWrite(LED_B, LOW);
+  }
+  else {
+    digitalWrite(LED_R, HIGH);
+    digitalWrite(LED_G, HIGH);
+    digitalWrite(LED_B, HIGH);
+  }
+  
+  // Output voltage, temperature
+  Serial.print("Raw analog reading: ");
+  Serial.print(V_raw);
+  Serial.print(" Voltage (V): ");
+  Serial.print(V_out);
+  Serial.print(" Temperature (°C): ");
+  Serial.print(C);
+  Serial.print(" Temperature (°F): "); // For reference
+  Serial.print(F);
+  
+  // Debug stuff
+  /*Serial.print(" Segment lower bound: ");
+  Serial.print(s ? V_mid[s - 1] : 0);
+  Serial.print(" Segment upper bound: ");
+  Serial.print(V_mid[s]);*/
+
+  Serial.println();
+  delay(500);
+}