MFRC-522 RFID Module

### Lesson Plan: Using the MFRC-522 RFID Module with the Raspberry Pi Pico WH


Hey adventurers! Today, we’re stepping into the world of contactless communication with the MFRC-522 RFID Module. RFID stands for Radio Frequency Identification, and this technology is used in everything from access control systems to inventory management. It’s a fantastic tool for projects that need to identify or track objects without physical contact. Ready to unlock the secrets of RFID? Let’s get started!

**Learning Objectives**

By the end of this lesson, you’ll be able to connect and use the MFRC-522 RFID Module with your Raspberry Pi Pico WH. You’ll learn to read data from RFID cards and tags and use this information to control other components. This skill is essential for creating projects that involve identification and access control. Let’s dive into the world of RFID!

**Materials Needed**

For this lesson, you’ll need a Raspberry Pi Pico WH, an MFRC-522 RFID Module, RFID cards and tags, a breadboard, jumper wires, a Micro USB cable, and your computer with a MicroPython IDE. These tools will help you harness the power of RFID technology in your projects.

**Background Information**

The MFRC-522 RFID Module operates at 13.56 MHz and can read and write data to RFID cards and tags. It communicates with the Raspberry Pi Pico over the SPI interface, which allows for fast and efficient data transfer. This module is widely used in applications like access control systems, attendance systems, and smart lockers.

**Circuit Diagram**

Before we build the circuit, let’s visualize it. The MFRC-522 RFID Module has eight pins: VCC, GND, RST, IRQ, MISO, MOSI, SCK, and SDA. We’ll connect VCC to the 3.3V pin on the Raspberry Pi Pico, GND to ground, and the SPI pins to the corresponding GPIO pins on the Raspberry Pi Pico.

**Step-by-Step Instructions**

Let’s get building! Start by placing the MFRC-522 RFID Module on the breadboard. Connect the VCC pin of the module to the 3.3V pin on the Raspberry Pi Pico. Connect the GND pin of the module to a ground pin on the Raspberry Pi Pico.

Next, connect the SPI pins as follows:
– RST to GP22
– SDA to GP21 (SPI CS)
– MOSI to GP19 (SPI TX)
– MISO to GP16 (SPI RX)
– SCK to GP18 (SPI SCK)

Once your circuit is set up, connect the Raspberry Pi Pico to your computer using the Micro USB cable. Open your MicroPython IDE, and let’s get ready to code.

**Sample Code**

Time to write some code to read data from the RFID module. Copy and paste the following code into your IDE and upload it to the Raspberry Pi Pico WH.

from machine import Pin, SPI
from mfrc522 import MFRC522
from time import sleep

# Initialize SPI and RFID module
spi = SPI(0, baudrate=1000000, polarity=0, phase=0, sck=Pin(18), mosi=Pin(19), miso=Pin(16))
rfid = MFRC522(spi, Pin(21), Pin(22))

print(“Place your card near the reader…”)

while True:
(status, tag_type) = rfid.request(rfid.REQIDL)

if status == rfid.OK:
(status, uid) = rfid.anticoll()
if status == rfid.OK:
print(“Card detected! UID: {}”.format(uid))
print(“Failed to read card”)


This code sets up the SPI interface and initializes the MFRC-522 RFID Module. It continuously scans for RFID cards and prints the UID (Unique Identifier) of any detected card to the console. It’s like having your own high-tech access control system!

**Testing and Troubleshooting**

Upload the code and place an RFID card or tag near the module. You should see the UID of the card printed to the console. If it’s not working, double-check your connections and ensure the module is correctly placed. Verify that the code is correctly uploaded to the Raspberry Pi Pico WH. Still having trouble? Take a deep breath and check your setup again. You’re on the right track!

**Applications and Extensions**

Now that you’ve got the basics down, let’s get creative. Try using the RFID module to control access to a system by only allowing recognized UIDs. You could also use it to log attendance or trigger events when specific cards are detected. The possibilities are endless, and the RFID module is your key to creating secure and interactive projects!

**Summary and Review**

Fantastic job! You’ve just mastered using the MFRC-522 RFID Module with the Raspberry Pi Pico WH and MicroPython. You learned how to connect the module, read RFID cards, and display the UID. These skills are crucial for building projects that require identification and access control. Keep experimenting, keep building, and most importantly, have fun!

Remember, the best way to learn is by doing, so keep exploring the amazing world of electronics. Happy building, and as always, stay curious!

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