Gravity: Serial Data Logger Wiki - DFRobot

Introduction

Compared to the previous MicroSD Card Module, this Gravity: Serial Data Logger can store data more conveniently, and supports direct data printing through serial port without additional codes. The Serial Data Logger provides onboard 128MB Flash memory, no more TF card required. It comes with a USB function, which means you can directly connect it to a PC computer to read the stored files without using a card reader. Meanwhile, with the onboard LED indicator, data writing status can be viewed visually. And the onboard SAVE key makes it easier to store data into separate files.

To avoid data recording error, please update the firmware for users who purchased before 2022/5/1.

• Unzip the download.7z
• Enter the folder download/download to find the file download_flash_sdk.bat
• Connect your module to the PC via a USB cable that can transfer data, double click download_flash_sdk.bat to burn the firmware.

For First Time Use

1. If the storage is not formatted, format the storage first. The file system is FAT32.
2. Power on the module for over 2 seconds (not from USB host) to make the module automatically generate the CONFIG.TXT file, and the SD light will blink once.
3. Check whether the CONFIG.TXT file is generated normally, if not, refer to FAQ please. You can change the module communication baud rate and file storage name by changing CONFIG.TXT file.

Baud: serial port communication baud rate select (00 indicates 2400 baud rate and 01 indicates 4800 baud rate). Data can be stored normally only when the module baud rate matches the one of the maincontroller serial print.

FIleNum: the serial number of the next new file (FileNum=0099, the name of the next generated file is FILE0099.txt). If the file already exists, the system skips this file and continues to search for the next file.

4. Connect the module to the maincontroller serial port to store data.

Note

1. Don't send data to the module serial port before CONFIG.TXT file is generated.
2. Don't connect the USB and serial port at the same time.
3. Connect a PC through USB. It is recommended to eject the USB flash drive before removing the module.

Features

• With USB function, no card reader required
• Onboard 128MB Flash memory, no TF card required
• Support multiple baud rates, good compatibility
• LED indicator for viewing data writing status visually

Applications

• Offline data collection
• Capture product debug logs
• Robots and drones debug

Specification

• Supply Voltage: 3.3V~5V
• Operating Current: 32mA
• USB Protocol: USB2.0
• Operating Temperature Range: -30℃~85℃
• Operating Humidity Range: 5%RH~85%RH
• Dimension: 32×27mm/1.26×1.06”

Pinout

The SD LED indicator indicates data interaction status between module and storage. It blinks when data is being written or a new file is being created.

Tutorial

Requirements

• Hardware
  • DFRduino UNO R3 x 1
  • Fermion: Serial Data Logger x 1
  • M-M/F-M/F-F Jumper wires

• Software
  • Arduino IDE

Connection Diagram

Sample Code 1 - Write Data

Write data to the module through Serial.print, save a file every once in a while.

#define SPIN 6  //Connect to the module Pin S, trigger to save files at low level 
uint16_t i = 0;

void setup(void)
{
  Serial.begin(9600);
  delay(2000);  //To aviod data lost, delay a period of time to wait for the module to start 
  pinMode(SPIN, OUTPUT);
  digitalWrite(SPIN, HIGH);
}

void loop(void)
{
  Serial.println(String(i));
  i++;
  if((i % 10) == 0){
    digitalWrite(SPIN, LOW);
    delay(500);
    digitalWrite(SPIN, HIGH);
  }
  delay(300);
}

FAQ

More Documents

• Schematics
• Dimensions
• DXF
• STP