.. note::

    Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

    **Why Join?**

    - **Expert Support**: Solve post-sale issues and technical challenges with help from our community and team.
    - **Learn & Share**: Exchange tips and tutorials to enhance your skills.
    - **Exclusive Previews**: Get early access to new product announcements and sneak peeks.
    - **Special Discounts**: Enjoy exclusive discounts on our newest products.
    - **Festive Promotions and Giveaways**: Take part in giveaways and holiday promotions.

    👉 Ready to explore and create with us? Click [|link_sf_facebook|] and join today!

.. _4.1.13_py_mcp3008:

4.1.10 Overheat Monitor(MCP3008)
=====================================

.. note::

   .. image:: ../img/mcp3008_and_adc0834.jpg
      :width: 25%
      :align: left
    

   Depending on your kit version, please identify whether you have **ADC0834** or **MCP3008** and proceed with the matching section.

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

You may want to make an overheat monitoring device that applies to
various situations, ex., in the factory, if we want to have an alarm and
the timely automatic turning off of the machine when there is a circuit
overheating. In this project, we will use thermistor, joystick, buzzer,
LED and LCD to make an smart temperature monitoring device whose
threshold is adjustable.

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

In this project, we need the following components.

.. image:: ../img/list2_Overheat_Monitor.png
    :width: 800
    :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_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_led`
        - |link_led_buy|
    *   - :ref:`cpn_joystick`
        - \-
    *   - :ref:`cpn_mcp3008`
        - \-
    *   - :ref:`cpn_transistor`
        - |link_transistor_buy|
    *   - :ref:`cpn_i2c_lcd`
        - |link_i2clcd1602_buy|
    *   - :ref:`cpn_thermistor`
        - |link_thermistor_buy|
    *   - :ref:`cpn_buzzer`
        - \-

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

============ ======== ======== ===
T-Board Name physical wiringPi BCM
SPICE0       Pin 24   10       8
SPIMOSI      Pin 19   12       10
SPIMISO      Pin 21   13       9
SPISCLK      Pin 23   14       11
GPIO22       Pin15    3        22
GPIO23       Pin16    4        23
GPIO24       Pin18    5        24
SDA1         Pin 3             
SCL1         Pin 5             
============ ======== ======== ===

.. image:: ../img/schematic_over_monitor_mcp3008.png
   :align: center

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

**Step 1:** Build the circuit.

.. image:: ../img/july24_3.1.8_overheat_monitor_mcp3008.png

**Step 2:** Set up the SPI interface and install the ``spidev`` library (see :ref:`spi_configuration` for detailed instructions). If you have already completed these steps, you can skip this.

**Step 3**: Go to the folder of the code.

.. raw:: html

   <run></run>

.. code-block:: 

    cd ~/raphael-kit/python

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

.. raw:: html

   <run></run>

.. code-block:: 

    sudo python3 4.1.13-2_OverheatMonitor.py

As the code runs, the current temperature and the high-temperature
threshold **40** are displayed on **I2C LCD1602**. If the current
temperature is larger than the threshold, the buzzer and LED are started
to alarm you.

**Joystick** here is for your pressing to adjust the high-temperature
threshold. Toggling the **Joystick** in the direction of X-axis and
Y-axis can adjust (turn up or down) the current high-temperature
threshold. Press the **Joystick** once again to reset the threshold to
initial value.

.. note::

    * If you get the error ``FileNotFoundError: [Errno 2] No such file or directory: '/dev/i2c-1'``, you need to refer to :ref:`i2c_config` to enable the I2C.
    * If you get ``ModuleNotFoundError: No module named 'smbus2'`` error, please run ``sudo apt install python3-smbus2``.
    * If the error ``OSError: [Errno 121] Remote I/O error`` appears, it means the module is miswired or the module is broken.
    * If the code and wiring are fine, but the LCD still does not display content, you can turn the potentiometer on the back to increase the contrast.


.. warning::

    If there is an error prompt  ``RuntimeError: Cannot determine SOC peripheral base address``, please refer to :ref:`faq_soc` 

**Code**

.. note::
    You can **Modify/Reset/Copy/Run/Stop** the code below. But before that, you need to go to  source code path like ``raphael-kit/python``. After modifying the code, you can run it directly to see the effect.

.. raw:: html

    <run></run>

.. code-block:: python

    #!/usr/bin/env python3

    import RPi.GPIO as GPIO
    import spidev
    import time
    import math
    import LCD1602

    # GPIO pin definitions
    JOY_BTN_PIN = 22  # Button pin
    BUZZER_PIN = 23   # Buzzer pin
    LED_PIN = 24      # LED pin

    # Initialize GPIO
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(JOY_BTN_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)
    GPIO.setup(BUZZER_PIN, GPIO.OUT)
    GPIO.setup(LED_PIN, GPIO.OUT)

    # Set initial upper temperature threshold
    upperTem = 40

    # Initialize SPI for MCP3008
    spi = spidev.SpiDev()
    spi.open(0, 0)
    spi.max_speed_hz = 1000000  # 1 MHz

    # Initialize LCD1602
    LCD1602.init(0x27, 1)

    def read_adc(channel):
        """
        Read analog value from MCP3008 (0–7)
        """
        if channel < 0 or channel > 7:
            return -1
        adc = spi.xfer2([1, (8 + channel) << 4, 0])
        value = ((adc[1] & 0x03) << 8) | adc[2]
        return value

    def get_joystick_value():
        """
        Reads the joystick values and returns a change value based on the joystick's position.
        """
        x_val = read_adc(1)
        y_val = read_adc(2)
        if x_val > 800:
            return 1
        elif x_val < 200:
            return -1
        elif y_val > 800:
            return -10
        elif y_val < 200:
            return 10
        else:
            return 0

    def upper_tem_setting():
        """
        Adjusts and displays the upper temperature threshold on the LCD.
        """
        global upperTem
        LCD1602.write(0, 0, 'Upper Adjust: ')
        change = int(get_joystick_value())
        upperTem += change
        strUpperTem = str(upperTem)
        LCD1602.write(0, 1, strUpperTem)
        LCD1602.write(len(strUpperTem), 1, '              ')
        time.sleep(0.1)

    def temperature():
        """
        Reads the current temperature from the sensor and returns it in Celsius.
        """
        analogVal = read_adc(0)
        Vr = 3.3 * analogVal / 1023.0
        if Vr == 0:
            return 0
        Rt = 10000.0 * (3.3 - Vr) / Vr
        tempK = 1.0 / (((math.log(Rt / 10000.0)) / 3950.0) + (1.0 / (273.15 + 25.0)))
        Cel = tempK - 273.15
        return round(Cel, 2)

    def monitoring_temp():
        """
        Monitors and displays the current temperature and upper temperature threshold. 
        Activates buzzer and LED if the temperature exceeds the upper limit.
        """
        global upperTem
        Cel = temperature()
        LCD1602.write(0, 0, 'Temp: ')
        LCD1602.write(0, 1, 'Upper: ')
        LCD1602.write(6, 0, str(Cel))
        LCD1602.write(7, 1, str(upperTem))
        time.sleep(0.1)
        if Cel >= upperTem:
            GPIO.output(BUZZER_PIN, GPIO.HIGH)
            GPIO.output(LED_PIN, GPIO.HIGH)
        else:
            GPIO.output(BUZZER_PIN, GPIO.LOW)
            GPIO.output(LED_PIN, GPIO.LOW)

    # Main loop
    try:
        lastState = GPIO.input(JOY_BTN_PIN)
        stage = 0
        while True:
            currentState = GPIO.input(JOY_BTN_PIN)
            if currentState == GPIO.HIGH and lastState == GPIO.LOW:
                stage = (stage + 1) % 2
                time.sleep(0.1)
                LCD1602.clear()
            lastState = currentState

            if stage == 1:
                upper_tem_setting()
            else:
                monitoring_temp()

    except KeyboardInterrupt:
        pass

    finally:
        LCD1602.clear()
        GPIO.cleanup()
        spi.close()

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

1. **Import Libraries**

   This section loads the required libraries for GPIO, SPI, LCD display, time delays, and math operations.

   .. code-block:: python

       #!/usr/bin/env python3
       import RPi.GPIO as GPIO
       import spidev
       import time
       import math
       import LCD1602

2. **GPIO and Device Setup**

   Define GPIO pin numbers for the joystick button, buzzer, and LED, and configure GPIO modes.

   .. code-block:: python

       JOY_BTN_PIN = 22  # Button pin
       BUZZER_PIN = 23   # Buzzer pin
       LED_PIN = 24      # LED pin

       GPIO.setmode(GPIO.BCM)
       GPIO.setup(JOY_BTN_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)
       GPIO.setup(BUZZER_PIN, GPIO.OUT)
       GPIO.setup(LED_PIN, GPIO.OUT)

3. **SPI and LCD Initialization**

   Start the SPI interface for MCP3008 and initialize the LCD1602 screen with I2C address 0x27.

   .. code-block:: python

       upperTem = 40
       spi = spidev.SpiDev()
       spi.open(0, 0)
       spi.max_speed_hz = 1000000

       LCD1602.init(0x27, 1)

4. **Read ADC Value**

   Reads analog data from MCP3008 ADC via SPI. Channel should be in range 0–7.

   .. code-block:: python

       def read_adc(channel):
           if channel < 0 or channel > 7:
               return -1
           adc = spi.xfer2([1, (8 + channel) << 4, 0])
           value = ((adc[1] & 0x03) << 8) | adc[2]
           return value

5. **Joystick Movement Detection**

   Checks X/Y axis values from the joystick and returns how much to change the threshold.

   .. code-block:: python

       def get_joystick_value():
           x_val = read_adc(1)
           y_val = read_adc(2)
           if x_val > 800:
               return 1
           elif x_val < 200:
               return -1
           elif y_val > 800:
               return -10
           elif y_val < 200:
               return 10
           else:
               return 0

6. **Adjust Upper Temperature Threshold**

   Displays "Upper Adjust" on the LCD and adjusts the threshold using joystick input.

   .. code-block:: python

       def upper_tem_setting():
           global upperTem
           LCD1602.write(0, 0, 'Upper Adjust: ')
           change = int(get_joystick_value())
           upperTem += change
           strUpperTem = str(upperTem)
           LCD1602.write(0, 1, strUpperTem)
           LCD1602.write(len(strUpperTem), 1, '              ')
           time.sleep(0.1)

7. **Temperature Calculation**

   Converts analog sensor reading to voltage, resistance, and finally temperature (Celsius) using Steinhart–Hart approximation.

   .. code-block:: python

       def temperature():
           analogVal = read_adc(0)
           Vr = 3.3 * analogVal / 1023.0
           if Vr == 0:
               return 0
           Rt = 10000.0 * (3.3 - Vr) / Vr
           tempK = 1.0 / (((math.log(Rt / 10000.0)) / 3950.0) + (1.0 / (273.15 + 25.0)))
           Cel = tempK - 273.15
           return round(Cel, 2)

8. **Temperature Monitoring**

   Continuously checks and displays temperature and upper limit. Turns on buzzer and LED if temperature exceeds the threshold.

   .. code-block:: python

       def monitoring_temp():
           global upperTem
           Cel = temperature()
           LCD1602.write(0, 0, 'Temp: ')
           LCD1602.write(0, 1, 'Upper: ')
           LCD1602.write(6, 0, str(Cel))
           LCD1602.write(7, 1, str(upperTem))
           time.sleep(0.1)
           if Cel >= upperTem:
               GPIO.output(BUZZER_PIN, GPIO.HIGH)
               GPIO.output(LED_PIN, GPIO.HIGH)
           else:
               GPIO.output(BUZZER_PIN, GPIO.LOW)
               GPIO.output(LED_PIN, GPIO.LOW)

9. **Main Program Logic**

   Toggles between temperature monitoring and threshold setting modes when the joystick button is pressed.

   .. code-block:: python

       try:
           lastState = GPIO.input(JOY_BTN_PIN)
           stage = 0
           while True:
               currentState = GPIO.input(JOY_BTN_PIN)
               if currentState == GPIO.HIGH and lastState == GPIO.LOW:
                   stage = (stage + 1) % 2
                   time.sleep(0.1)
                   LCD1602.clear()
               lastState = currentState

               if stage == 1:
                   upper_tem_setting()
               else:
                   monitoring_temp()

10. **Cleanup on Exit**

    Ensures proper shutdown of GPIO and SPI resources when Ctrl+C is pressed.

    .. code-block:: python

        except KeyboardInterrupt:
            pass
        finally:
            LCD1602.clear()
            GPIO.cleanup()
            spi.close()