Arduino

Record Data To Sd Card With Attiny85

by Staff Writer
4 min read

Understanding the ATTiny85 Microcontroller

The ATTiny85 is a compact and powerful microcontroller from Atmel, capable of performing numerous tasks despite its small size. Ideal for projects requiring a lightweight solution, it contains 8 kilobytes of programmable flash memory, 512 bytes of SRAM, and 6 I/O pins. This microcontroller is commonly used in embedded systems, wearables, and small-scale automation projects.

Required Components for Data Logging

To set up data logging on an SD card using the ATTiny85, you will need several components. The primary components involved include:

  • ATTiny85 Microcontroller: The core of the system, responsible for processing data.
  • MicroSD Card Module: This interface allows for easy connection to the microcontroller and handles data storage.
  • Level Shifter: Since the ATTiny85 operates at 5V logic levels, a level shifter is required to communicate with the 3.3V-compatible SD card module.
  • Power Supply: A stable 5V source is essential for powering the ATTiny85 and the SD card module.
  • Wires and Breadboard: For establishing connections and prototyping the circuit.

Wiring the Components

Establishing the correct connections is crucial for the functionality of the system. Here’s how to wire the components:

  1. ATTiny85 Connections:

    • Connect Pin 1 (Reset) to a pull-up resistor to VCC (5V).
    • Pin 2 (Digital I/O) – connect to the SD card module’s CS (Chip Select) pin.
    • Pin 3 (Digital I/O) – connect to the SD card module’s MOSI (Master Out Slave In) pin.
    • Pin 4 (Digital I/O) – connect to the SD card module’s MISO (Master In Slave Out) pin.
    • Pin 5 (Digital I/O) – connect to the SD card module’s SCK (Clock) pin.
    • Connect Pin 8 (VCC) to the power supply and Pin 4 (GND) to ground.

  2. SD Card Module:

    • Ensure the SD card module is powered correctly, using the same ground reference as the ATTiny85.
  3. Level Shifter (If necessary):
    • Connect the level shifter between the ATTiny85 and the SD card module to ensure proper voltage levels are maintained during data transmission.
See also  Get Esp32 Chip Id Into A String Variable Arduino C Newbie Here

Programming the ATTiny85

To record data onto the SD card, the ATTiny85 must be programmed to manage file creation, writing, and closing protocols. The following steps outline how to do this:

  1. Install Required Libraries: Download the SPI and SD libraries compatible with the ATTiny85. These libraries facilitate communication with the SD card.

  2. Set Up Your Environment: Use the Arduino IDE for coding. Make sure you have the board definitions for the ATTiny series installed.

  3. Write the Code: The code will need to initialize the SD card, create a file, write data to it, and then close the file appropriately. Here’s a simplified version of the key sections:

    #include <SPI.h>
#include <SD.h>

const int chipSelect = 2; // Pin connected to the SD card CS

void setup() {
   pinMode(chipSelect, OUTPUT);
   digitalWrite(chipSelect, HIGH);
   Serial.begin(9600);

   if (!SD.begin(chipSelect)) {
       Serial.println("SD card initialization failed!");
       return;
   }

   File dataFile = SD.open("data.txt", FILE_WRITE);
   if (dataFile) {
       dataFile.println("Sample data: " + String(millis())); // Replace with your actual data
       dataFile.close();
   } else {
       Serial.println("Error opening file for writing");
   }
}

void loop() {
   // Your code for continuous data collection can be added here
}
  4. Upload and Test: Upload the code to the ATTiny85 and test the system. Ensure data is being written correctly to the SD card.

Troubleshooting Common Issues

During the setup and operation, a few common issues may arise:

  • SD Card Not Recognized: Ensure that the wiring is correct and that the card is formatted to FAT32.
  • Data Not Written: Double-check that the file is being opened in write mode. Ensure sufficient power supply is available and that no interruptions occur during writing.
  • Microcontroller Limits: Given the limited memory of the ATTiny85, be cautious of the size of data being logged. Optimize the program to manage memory efficiently.
See also  Int Vs Uint8 T Vs Uint16 T

FAQ

1. Can I use a different microcontroller instead of ATTiny85?
Yes, other microcontrollers can be used, but make sure they provide compatible voltage levels and have sufficient I/O pins to interface with the SD card module.

2. Is it possible to format the SD card from the microcontroller?
Formatting an SD card is complex and generally not done through microcontroller code due to the intricacies involved. It is best to format the SD card via a computer before usage.

3. How much data can the ATTiny85 handle at once?
The data storage capability is more dependent on the SD card capacity than the ATTiny85, but keep in mind that the microcontroller has limited SRAM for processing data at any given time.

You may also like