JSON Objects Explained

 

JSON Objects: Structured Data Explained

JSON, or JavaScript Object Notation, is a widely used format for representing structured data. It's concise, human-readable, and easily understood by both humans and machines, making it a popular choice for web applications, APIs, and data exchange. Let's dive into the essence of JSON objects:

Imagine a box: This box represents a JSON object. Inside the box, you can store items, but not just any items – only key-value pairs. Just like labels and their corresponding contents, each key uniquely identifies a piece of data (the value).

Structure Matters:

• Keys: They act as unique identifiers, written in double quotes and always strings. Imagine them as labels on your box compartments.
• Values: These can be various data types: strings, numbers, booleans (true/false), null, or even arrays and other objects (nesting allowed!). They represent the actual information stored within each compartment.
• Commas & Braces: Commas separate key-value pairs, and curly braces ({ and }) enclose the entire object, defining its boundaries.

Bringing it Together:

Here's a simple example:

JSON

{ "name": "Alice", "age": 30, "isStudent": true, "hobbies": ["reading", "hiking", "coding"] }

Key Points to Remember:

• Order doesn't matter: Unlike some data structures, the order of key-value pairs within a JSON object doesn't affect its meaning.
• No duplicate keys: Each key within an object must be unique. You can't have two keys with the same name.
• Nesting allowed: Objects can contain other objects or arrays, creating complex data structures.

Applications of JSON Objects:

JSON objects are incredibly versatile and find use in various contexts:

• Web APIs: They seamlessly transfer data between servers and clients in web applications.
• Configuration files: They store settings and options for various applications.
• Data storage: They provide a lightweight and flexible way to store structured data.
• Data exchange: They facilitate data exchange between different systems and platforms.

Difference between the Raspberry Pico and the Raspberry Pico W

The main difference between the Raspberry Pi Pico and the Raspberry Pi Pico W is wireless connectivity.

Here's a breakdown:

Raspberry Pi Pico:

• No Wi-Fi or Bluetooth
• More affordable
• Slightly smaller footprint
• Ideal for projects that don't need internet access (e.g., robotics, data logging)

Raspberry Pi Pico W:

• Built-in Wi-Fi 4.2 chip (802.11 b/g/n)
• More expensive than the Pico
• Slightly larger footprint due to the Wi-Fi chip
• Perfect for projects requiring internet access (e.g., IoT devices, remote control, data transmission)

Other minor differences:

• Pin configuration: The Pico W has a slightly different pin configuration for one GPIO pin (GP0) due to the Wi-Fi chip. However, this shouldn't affect most projects.
• Onboard LED: The onboard LED is connected differently on the Pico W, but you can still use it for blinking and other simple tasks.
• Debug header: The debug header is repositioned slightly on the Pico W due to the Wi-Fi chip placement.

Choosing the right Pico:

If you need wireless connectivity for your project, the Pico W is the obvious choice. But if you prioritize cost, size, or don't need internet access, the standard Pico is a good option.

ChatGPT Writes and Explains the Code line by line

ChatGPT Tutorial:

Use chatGPT to help with coding here is one example.

New Chat:

Write code in MicroPython to display temperature reading from internal sensor in celsius and fahrenheit on a SSD1306 display every second. Raspberry Pi Pico board.

Open THONNY IDE copy code from ChatGPT

main.py

import machine

import ssd1306

import utime

# Initialize the I2C bus and the SSD1306 display

i2c = machine.I2C(0, sda=machine.Pin(8), scl=machine.Pin(9), freq=400000)

oled = ssd1306.SSD1306_I2C(128, 32, i2c)

# Define a function to convert Celsius to Fahrenheit

def c_to_f(celsius):

    return (celsius * 1.8) + 32

while True:

    # Read the temperature from the internal sensor

    temp_celsius = machine.ADC(4).read_u16() * 3.3 / 65535 * 100 - 50

    temp_fahrenheit = c_to_f(temp_celsius)

    

    # Clear the display and print the temperature readings

    oled.fill(0)

    oled.text("Temp (C): {:.1f}".format(temp_celsius), 0, 0)

    oled.text("Temp (F): {:.1f}".format(temp_fahrenheit), 0, 10)

    oled.show()

    

    # Wait for 1 second before reading the temperature again

    utime.sleep(1)

ChatGPT explaines the code:

MicroPython code that reads the temperature from the internal sensor and displays it on an SSD1306 OLED display. The code uses the ADC (Analog-to-Digital Converter) to read the temperature and converts it from Celsius to Fahrenheit using the c_to_f function. The temperature readings are then displayed on the OLED display using the oled.text method.

The main loop of the code continuously reads the temperature and updates the display every second using the utime.sleep function.

Here's a step-by-step breakdown of what the code does:

1. Import the necessary modules:

import machine

import ssd1306

import utime

2. Initialize the I2C bus and the SSD1306 display:

i2c = machine.I2C(0, sda=machine.Pin(8), scl=machine.Pin(9), freq=400000)

oled = ssd1306.SSD1306_I2C(128, 32, i2c)

3. Define a function to convert Celsius to Fahrenheit:

def c_to_f(celsius):

    return (celsius * 1.8) + 32

4. Enter the main loop:

while True:

5. Read the temperature from the internal sensor using the ADC:

 temp_celsius = machine.ADC(4).read_u16() * 3.3 / 65535 * 100 - 50

6. Convert the temperature from Celsius to Fahrenheit using the c_to_f function:

 temp_fahrenheit = c_to_f(temp_celsius)

7. Clear the OLED display using the oled.fill method:

oled.fill(0)

8. Print the temperature readings on the OLED display using the oled.text method:

oled.text("Temp (C): {:.1f}".format(temp_celsius), 0, 0)

    oled.text("Temp (F): {:.1f}".format(temp_fahrenheit), 0, 10)

9. Update the OLED display using the oled.show method:

oled.show()

10. Wait for 1 second before reading the temperature again using the utime.sleep function:

utime.sleep(1)

Pinouts for SSD1306 and Raspberry Pico:

4 Digit TM1637 Display Module For Raspberry Pico

4 Digit Display Module

TM1637 is a chip commonly used to drive 7-segment LED displays and other types of digital displays. It communicates with microcontrollers using a 2-wire interface, and supports various functions such as setting brightness and displaying decimal points.

Pinouts :

1. CLK
2. DIO
3. VCC
4. GND