HiLetgo OpenLog Serial Data Logger User Manual

1. Product Overview

The HiLetgo OpenLog is an open-source data logger designed for recording serial data. It functions as a black box, storing large volumes of serial data generated by various projects for scientific analysis or debugging purposes. The device operates via a simple serial connection and supports microSD cards for data storage.

It is built around an ATmega328 microcontroller, running at 16MHz. The OpenLog is capable of logging data to low-cost microSD cards with capacities up to 64GB, formatted as FAT16 or FAT32 file types.

Key Features:

• VCC Input: 3.3V-12V (Recommended 3.3V-5V)
• Data Storage: Logs to microSD FAT16/32 cards up to 64GB.
• Interface: Simple command interface via serial connection.
• Baud Rates: Configurable up to 115200bps.
• Microcontroller: Preprogrammed ATmega328 with bootloader.
• Connectivity: Four SPI pogo pins for advanced interfacing.
• Status Indicators: Two LEDs to indicate writing status.
• Power Consumption: Approximately 2mA idle, 6mA at maximum recording rate.

Figure 1: Front view of the HiLetgo OpenLog Serial Data Logger board, showing the ATmega328 chip and header pins. This image illustrates the compact design and primary components of the data logger.

Figure 2: Rear view of the HiLetgo OpenLog Serial Data Logger board, highlighting the microSD card slot and additional header pins. This view demonstrates where the microSD card is inserted for data storage.

2. Setup

2.1 Package Contents

Verify that your package contains the following items:

• 1 x HiLetgo Serial Data Logger Open Source Data Recorder for Openlog

Figure 3: Various packaging options for the HiLetgo OpenLog, including sealed bags and a small cardboard box. This image provides an idea of how the product may be packaged upon arrival.

2.2 Power Supply Connection

Connect the OpenLog to a power source within the recommended voltage range of 3.3V to 5V. The device supports a wider input range of 3.3V to 12V, but optimal performance and longevity are achieved within the recommended range.

• Identify the VCC and GND pins on the OpenLog board.
• Connect VCC to your power supply's positive output (3.3V-5V).
• Connect GND to your power supply's ground.

2.3 MicroSD Card Preparation

The OpenLog requires a microSD card for data storage. Ensure the card is properly formatted before use.

• Obtain a microSD card with a capacity between 64MB and 64GB.
• Format the microSD card to either FAT16 or FAT32 file system. Most operating systems provide tools for this.
• Insert the prepared microSD card into the slot on the OpenLog board. Ensure it clicks into place securely.

3. Operation

3.1 Serial Connection

The OpenLog communicates via a simple serial connection (TTL level). You will need a USB-to-serial converter or a microcontroller with a serial port to interact with it.

• Connect the TX pin of your host device (e.g., Arduino, USB-to-serial converter) to the RXI pin of the OpenLog.
• Connect the RX pin of your host device to the TXO pin of the OpenLog.
• Ensure GND is connected between both devices.
• Optionally, connect the DTR pin for automatic reset functionality, if supported by your host.

3.2 Command Interface

The OpenLog uses a simple command interface. When powered on, it typically enters data logging mode. To access the command mode, send three '!' characters within one second via the serial connection.

Common commands include:

• `new`: Creates a new log file.
• `ls`: Lists files on the microSD card.
• `dump [filename]`: Dumps the content of a specified file to the serial port.
• `baud [rate]`: Sets the serial baud rate (e.g., `baud 9600`, `baud 115200`).
• `exit`: Exits command mode and returns to data logging.

Refer to the OpenLog official documentation for a complete list of commands and their usage.

3.3 Data Logging

Once configured, any data sent to the OpenLog's RXI pin will be written to the currently active log file on the microSD card. The two onboard LEDs provide status indication:

• One LED typically indicates power or activity.
• The other LED flashes during data writing operations.

4. Maintenance

4.1 Firmware Updates

The OpenLog comes preprogrammed with firmware. However, if you need to update or re-flash the firmware, please note the following:

• The latest versions of the OpenLog firmware may not compile correctly with newer Arduino IDE versions (e.g., Arduino 1.6.7 and later).
• It is recommended to use Arduino IDE version 1.6.5 for compiling and uploading OpenLog firmware.
• Firmware can be uploaded via the ISP header (four SPI pogo pins) using an AVR programmer, or potentially via the serial bootloader if present and accessible.

4.2 General Care

• Keep the device in a dry environment, away from moisture and extreme temperatures.
• Avoid static discharge when handling the board.
• Do not apply excessive force when inserting or removing the microSD card.

5. Troubleshooting

5.1 Device Not Responding / No Data Logging

• Check Power: Ensure the OpenLog is receiving stable power within the 3.3V-5V recommended range.
• Serial Connections: Verify that TX, RX, and GND connections are correct and secure between the OpenLog and your host device.
• Baud Rate Mismatch: Confirm that the serial baud rate on your host device matches the OpenLog's configured baud rate (default is often 9600 or 115200).
• MicroSD Card:
  • Ensure the microSD card is properly inserted and securely seated.
  • Verify the microSD card is formatted as FAT16 or FAT32.
  • Test with a different microSD card to rule out card issues.
• Missing Firmware: Some units may ship without pre-loaded firmware or bootloader. If the device does not respond to serial commands or log data, you may need to flash the OpenLog firmware and bootloader using an AVR programmer (e.g., USBasp, Arduino as ISP) and the Arduino IDE (version 1.6.5 recommended).

5.2 Slow Data Logging

• MicroSD Card Speed: Use a higher-speed microSD card (e.g., Class 10 or higher) for demanding logging applications.
• Baud Rate: Ensure your serial communication is set to the highest stable baud rate for your application (up to 115200bps).
• Data Buffer: While the OpenLog can draw up to 6mA when recording a 512-byte buffer, continuous high-speed data streams (e.g., 115200bps) will approach this limit and may experience bottlenecks if the microSD card cannot keep up.

6. Specifications

7. Support and Warranty

7.1 Technical Support

For technical assistance or inquiries regarding the HiLetgo OpenLog Serial Data Logger, please contact HiLetgo support. Information regarding support can often be found on the manufacturer's website or through the retailer where the product was purchased.

Based on product packaging, you may find support information at: www.hiletgo.com or by emailing support@hiletgo.com.

Figure 4: Close-up of HiLetgo product packaging, displaying the manufacturer's website and support email address for customer assistance. This image confirms the contact details for technical support.

7.2 Warranty Information

Warranty terms and conditions for the HiLetgo OpenLog are typically provided at the point of purchase or on the official HiLetgo website. Please retain your proof of purchase for any warranty claims. The standard return policy for this product is 30 days for refund or replacement.