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.. _3.1.4_c:

3.1.4 Smart Fan
======================

Introduction
-----------------

In this project, we will use motors, buttons and thermistors to make a
manual + automatic smart fan whose wind speed is adjustable.

Required Components
------------------------------

In this project, we need the following components. 

.. image:: ../img/list_Smart_Fan.png
    :align: center

It's definitely convenient to buy a whole kit, here's the link: 

.. list-table::
    :widths: 20 20 20
    :header-rows: 1

    *   - Name	
        - ITEMS IN THIS KIT
        - LINK
    *   - Raphael Kit
        - 337
        - |link_Raphael_kit|

You can also buy them separately from the links below.

.. list-table::
    :widths: 30 20
    :header-rows: 1

    *   - COMPONENT INTRODUCTION
        - PURCHASE LINK

    *   - :ref:`cpn_gpio_extension_board`
        - |link_gpio_board_buy|
    *   - :ref:`cpn_breadboard`
        - |link_breadboard_buy|
    *   - :ref:`cpn_wires`
        - |link_wires_buy|
    *   - :ref:`cpn_resistor`
        - |link_resistor_buy|
    *   - :ref:`cpn_power_module`
        - \-
    *   - :ref:`cpn_thermistor`
        - |link_thermistor_buy|
    *   - :ref:`cpn_l293d`
        - \-
    *   - :ref:`cpn_adc0834`
        - \-
    *   - :ref:`cpn_button`
        - |link_button_buy|
    *   - :ref:`cpn_motor`
        - |link_motor_buy|

Schematic Diagram
------------------------

============ ======== ======== ===
T-Board Name physical wiringPi BCM
GPIO17       Pin 11   0        17
GPIO18       Pin 12   1        18
GPIO27       Pin 13   2        27
GPIO22       Pin 15   3        22
GPIO5        Pin 29   21       5
GPIO6        Pin 31   22       6
GPIO13       Pin 33   23       13
============ ======== ======== ===

.. image:: ../img/Schematic_three_one4.png
   :align: center

Experimental Procedures
-----------------------------

**Step 1:** Build the circuit.

.. image:: ../img/image245.png
    :align: center

.. note::
    The power module can apply a 9V battery with the 9V Battery
    Buckle in the kit. Insert the jumper cap of the power module into the 5V
    bus strips of the breadboard.

.. image:: ../img/image118.jpeg
    :align: center

**Step 2**: Get into the folder of the code.

.. raw:: html

   <run></run>

.. code-block:: 

    cd ~/raphael-kit/c/3.1.4/

**Step 3**: Compile.

.. raw:: html

   <run></run>

.. code-block:: 

    gcc 3.1.4_SmartFan.c -lwiringPi -lm

**Step 4**: Run the executable file above.

.. raw:: html

   <run></run>

.. code-block:: 

    sudo ./a.out

As the code runs, start the fan by pressing the button. Every time you
press, 1 speed grade is adjusted up or down. There are **5** kinds of
speed grades: **0~4**. When set to the 4\ :sup:`th` speed grade and you
press the button, the fan stops working with a **0** wind speed.

Once the temperature goes up or down for more than 2℃, the speed
automatically gets 1-grade faster or slower.

.. note::

    If it does not work after running, or there is an error prompt: \"wiringPi.h: No such file or directory\", please refer to :ref:`install_wiringpi`.

Code
--------

.. code-block:: c

    #include <wiringPi.h>
    #include <stdio.h>
    #include <softPwm.h>
    #include <math.h>

    typedef unsigned char uchar;
    typedef unsigned int uint;

    #define ADC_CS      0
    #define ADC_CLK     1
    #define ADC_DIO     2
    #define MotorPin1   21
    #define MotorPin2   22
    #define MotorEnable 23
    #define BtnPin      3

    uchar get_ADC_Result(uint channel)
    {
        uchar i;
        uchar dat1=0, dat2=0;
        int sel = channel > 1 & 1;
        int odd = channel & 1;

        digitalWrite(ADC_CLK, 1);
        delayMicroseconds(2);
        digitalWrite(ADC_CLK, 0);
        delayMicroseconds(2);

        pinMode(ADC_DIO, OUTPUT);
        digitalWrite(ADC_CS, 0);
        // Start bit
        digitalWrite(ADC_CLK,0);
        digitalWrite(ADC_DIO,1);    delayMicroseconds(2);
        digitalWrite(ADC_CLK,1);    delayMicroseconds(2);
        //Single End mode
        digitalWrite(ADC_CLK,0);
        digitalWrite(ADC_DIO,1);    delayMicroseconds(2);
        digitalWrite(ADC_CLK,1);    delayMicroseconds(2);
        // ODD
        digitalWrite(ADC_CLK,0);
        digitalWrite(ADC_DIO,odd);  delayMicroseconds(2);
        digitalWrite(ADC_CLK,1);    delayMicroseconds(2);
        //Select
        digitalWrite(ADC_CLK,0);
        digitalWrite(ADC_DIO,sel);    delayMicroseconds(2);
        digitalWrite(ADC_CLK,1);

        digitalWrite(ADC_DIO,1);    delayMicroseconds(2);
        digitalWrite(ADC_CLK,0);
        digitalWrite(ADC_DIO,1);    delayMicroseconds(2);

        for(i=0;i<8;i++)
        {
            digitalWrite(ADC_CLK,1);    delayMicroseconds(2);
            digitalWrite(ADC_CLK,0);    delayMicroseconds(2);

            pinMode(ADC_DIO, INPUT);
            dat1=dat1<<1 | digitalRead(ADC_DIO);
        }

        for(i=0;i<8;i++)
        {
            dat2 = dat2 | ((uchar)(digitalRead(ADC_DIO))<<i);
            digitalWrite(ADC_CLK,1);    delayMicroseconds(2);
            digitalWrite(ADC_CLK,0);    delayMicroseconds(2);
        }

        digitalWrite(ADC_CS,1);
        pinMode(ADC_DIO, OUTPUT);
        return(dat1==dat2) ? dat1 : 0;
    }

    int temperture(){
        unsigned char analogVal;
        double Vr, Rt, temp, cel, Fah;
        analogVal = get_ADC_Result(0);
        Vr = 5 * (double)(analogVal) / 255;
        Rt = 10000 * (double)(Vr) / (5 - (double)(Vr));
        temp = 1 / (((log(Rt/10000)) / 3950)+(1 / (273.15 + 25)));
        cel = temp - 273.15;
        Fah = cel * 1.8 +32;
        int t=cel;
        return t;
    }

    int motor(int level){
        if(level==0){
            digitalWrite(MotorEnable,LOW);
            return 0;
        }
        if (level>=4){
            level =4;
        }
        digitalWrite(MotorEnable,HIGH);
        softPwmWrite(MotorPin1, level*25);
        return level;    
    }
    void setup(){
        if(wiringPiSetup() == -1){ //when initialize wiring failed,print messageto screen
            printf("setup wiringPi failed !");
            return;
        }
        softPwmCreate(MotorPin1,  0, 100);
        softPwmCreate(MotorPin2,  0, 100);
        pinMode(MotorEnable,OUTPUT);
        pinMode(BtnPin,INPUT);
        pinMode(ADC_CS,  OUTPUT);
        pinMode(ADC_CLK, OUTPUT);
    }

    int main(void)
    {
        setup();
        int currentState,lastState=0;
        int level = 0;
        int currentTemp,markTemp=0;
        while(1){
            currentState=digitalRead(BtnPin);
            currentTemp=temperture();
            if (currentTemp<=0){continue;}
            if (currentState==1&&lastState==0){
                level=(level+1)%5;
                markTemp=currentTemp;
                delay(500);
            }
            lastState=currentState;
            if (level!=0){
                if (currentTemp-markTemp<=-2){
                    level=level-1;
                    markTemp=currentTemp;
                }
                if (currentTemp-markTemp>=2){
                    level=level+1;
                    markTemp=currentTemp;
                }
            }
            level=motor(level);
        }
        return 0;
    }

Code Explanation
----------------------

.. code-block:: c

    int temperture(){
        unsigned char analogVal;
        double Vr, Rt, temp, cel, Fah;
        analogVal = get_ADC_Result(0);
        Vr = 5 * (double)(analogVal) / 255;
        Rt = 10000 * (double)(Vr) / (5 - (double)(Vr));
        temp = 1 / (((log(Rt/10000)) / 3950)+(1 / (273.15 + 25)));
        cel = temp - 273.15;
        Fah = cel * 1.8 +32;
        int t=cel;
        return t;
    }

Temperture() works by converting thermistor values read by ADC0834 into
temperature values. Refer to :ref:`2.2.2_c` for more details.

.. code-block:: c

    int motor(int level){
        if(level==0){
            digitalWrite(MotorEnable,LOW);
            return 0;
        }
        if (level>=4){
            level =4;
        }
        digitalWrite(MotorEnable,HIGH);
        softPwmWrite(MotorPin1, level*25);
        return level;    
    }

This function controls the rotating speed of the motor. The range of the
**Level**: **0-4** (level **0** stops the working motor). One level
adjustment stands for a **25%** change of the wind speed.

.. code-block:: c

    int main(void)
    {
        setup();
        int currentState,lastState=0;
        int level = 0;
        int currentTemp,markTemp=0;
        while(1){
            currentState=digitalRead(BtnPin);
            currentTemp=temperture();
            if (currentTemp<=0){continue;}
            if (currentState==1&&lastState==0){
                level=(level+1)%5;
                markTemp=currentTemp;
                delay(500);
            }
            lastState=currentState;
            if (level!=0){
                if (currentTemp-markTemp<=-2){
                    level=level-1;
                    markTemp=currentTemp;
                }
                if (currentTemp-markTemp>=2){
                    level=level+1;
                    markTemp=currentTemp;
                }
            }
            level=motor(level);
        }
        return 0;
    }

The function **main()** contains the whole program process as shown:

1) Constantly read the button state and the current temperature.

2) Every press makes level\ **+1** and at the same time, the temperature
   is updated. The **Level** ranges **1~4**.

3) As the fan works ( the level is **not 0**), the temperature is under
   detection. A **2℃\ +** change causes the up and down of the level.

4) The motor changes the rotating speed with the **Level**.