Added fully working code

README.md

@@ -1,2 +1,14 @@
-# air_throttle
-Air flow controlled by throttle with stepper motor
+# Air throttle
+Air flow controlled by throttle valve with stepper motor.
+A Hall-effect sensor detects when a stove is running and open the throttle. 
+Otherwise the throttle is closed.
+
+## Hardware
+
+### List of components
+* SparkFun Pro Micro 5V 16MHz
+* stepper motor 28BYJ-48 
+* ULN2003 driver for stepper motors
+* Hall-effect sensor ACS712 - 20A
+* simple ventilation throttle valve
+* 0.96 OLED display (optionally)

air_throttle.ino

@@ -0,0 +1,67 @@
+/*  
+ * Hardware:
+ * - board SparkFun Pro Micro 5V 16MHz.
+ * - step motor 28BYJ-48 with ULN2003 driver
+ * - hall sensor ACS712 - 20A.
+ * 
+*/
+
+#include <ACS712.h>
+#include <Stepper.h>
+
+// Motor.
+const int steps = 32;             // the number of motor steps.
+const int rotate_360 = 2048;      // 32*64 - because of gear.
+Stepper motor(steps, 6, 8, 7, 9); // pay attention to pins order. Current order is proper.
+
+// HALL effect sensor.
+// SparFun has 5.0 volt with a max value of 1023 steps.
+// ACS712 5A  uses 185 mV per A.
+// ACS712 20A uses 100 mV per A.  <<-----------
+// ACS712 30A uses  66 mV per A.
+ACS712 acs(A0, 5.0, 1023, 100);
+
+
+void setup() {
+  // Init rotor.
+  motor.setSpeed(800);
+
+  // Init HALL sensor.
+  acs.autoMidPoint();
+}
+
+
+bool is_stove_running   = false;
+bool is_throttle_opened = false;
+int mA; // the value taken from Hall sensor (in miliampers).
+
+void loop() {
+  // Read current.
+  mA = acs.mA_AC();
+  //Serial.println(mA);
+
+  // Stove is running.
+  is_stove_running = (mA > 200) ? true : false; 
+
+  // Run motor if needed.
+  if (is_stove_running && !is_throttle_opened) {
+    open_throttle(motor);
+    is_throttle_opened = true;
+  } 
+  else if (!is_stove_running && is_throttle_opened) {
+    close_throttle(motor);
+    is_throttle_opened = false;
+  }
+
+  delay(500);
+}
+
+
+void open_throttle (Stepper motor) {
+  motor.step(rotate_360/4); // 512 == turn 90 deg.
+}
+
+void close_throttle (Stepper motor) {
+  motor.step(-rotate_360/4); // 512 == turn 90 deg.
+}
+

air_throttle_with_oled.ino

@@ -0,0 +1,103 @@
+#include <ACS712.h>
+#include <Stepper.h>
+#include <Adafruit_SSD1306.h>
+#include <Adafruit_GFX.h>
+
+// OLED display.
+#define OLED_ADDR   0x3C
+Adafruit_SSD1306 display(-1);
+
+// Motor.
+const int steps = 32;             // the number of motor steps.
+const int rotate_360 = 2048;      // 32*64 - because of gear.
+Stepper motor(steps, 6, 8, 7, 9); // pay attention to pins order. Current order is proper.
+
+// HALL effect sensor.
+// SparFun has 5.0 volt with a max value of 1023 steps.
+// ACS712 5A  uses 185 mV per A.
+// ACS712 20A uses 100 mV per A.  <<-----------
+// ACS712 30A uses  66 mV per A.
+ACS712 acs(A0, 5.0, 1023, 100);
+
+
+void setup() {
+  // Init rotor.
+  motor.setSpeed(800);
+
+  // Init HALL sensor.
+  //pinMode(A0, INPUT);
+  acs.autoMidPoint();
+
+  // Init and clear OLED display.
+  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
+  display.clearDisplay();
+  display.display();
+  display.setTextColor(WHITE);
+}
+
+
+bool is_stove_running   = false;
+bool is_throttle_opened = false;
+int mA; // the value taken from Hall sensor (in miliampers).
+
+void loop() {
+  // Read current.
+  mA = acs.mA_AC();
+  display_hall(mA, is_throttle_opened);
+  //Serial.println(mA);
+
+  // Stove is running.
+  is_stove_running = (mA > 200) ? true : false; 
+
+  // Run motor if needed.
+  if (is_stove_running && !is_throttle_opened) {
+    display_throttle_state("opening...");
+    open_throttle(motor);
+    is_throttle_opened = true;
+  } 
+  else if (!is_stove_running && is_throttle_opened) {
+    display_throttle_state("closing...");
+    close_throttle(motor);
+    is_throttle_opened = false;
+  }
+
+  delay(500);
+}
+
+void open_throttle (Stepper motor) {
+  motor.step(rotate_360/4); // 512 == turn 90 deg.
+}
+
+void close_throttle (Stepper motor) {
+  motor.step(-rotate_360/4); // 512 == turn 90 deg.
+}
+
+// Views definitions.
+void display_hall(int hall, bool is_throttle_opened) {
+  display.clearDisplay();
+  display.setTextSize(1);
+  display.setCursor(0, 0);
+  display.print("Hall [mA]:\n");
+  display.setTextSize(2);
+  display.print(hall);
+  display.print("\n");
+  display.setTextSize(1);
+  display.print("Throttle: ");
+  if (is_throttle_opened) {
+    display.print("opened");
+  } else {
+    display.print("closed");
+  }
+  display.display();
+}
+
+void display_throttle_state(String msg) {
+  display.clearDisplay();
+  display.setTextSize(1);
+  display.setCursor(0, 0);
+  display.print("Throttle:\n");
+  display.setTextSize(2);
+  display.print(msg);
+  display.display();
+}
+