LILYGO TTGO T-Call V1.4 SIM800L ESP32 Wireless Module User Manual

1. Product Overview

The LILYGO TTGO T-Call V1.4 is a versatile development board integrating an ESP32 microcontroller with a SIM800L GSM/GPRS module. This combination provides comprehensive wireless communication capabilities including Wi-Fi, Bluetooth, and cellular connectivity, making it ideal for various Internet of Things (IoT) and mobile communication projects. It also supports GPS functionality and features a TF card slot for storage, along with options for 18650 battery power and solar charging.

Figure 1: Front view of the LILYGO TTGO T-Call V1.4 module, showing the ESP32-WROVER-E chip and various components.

Figure 2: Back view of the LILYGO TTGO T-Call V1.4 module, highlighting the SIM800L module and SIM card slot.

2. Setup Guide

2.1 Hardware Assembly

1. Antenna Connection:

   Carefully connect the provided SIM antenna to the module's antenna connector. Ensure a secure fit without applying excessive force to avoid damaging the antenna base.

   

   Figure 3: Illustration showing the correct method for connecting the antenna to prevent damage.

2. Nano SIM Card Insertion:

   Insert a Nano SIM card into the designated SIM card slot on the module. Ensure the card is oriented correctly as indicated on the board.

   

   Figure 4: Close-up of the Nano SIM card slot.

3. 18650 Battery Connection (Optional):

   The module supports an external 18650 battery for portable power. Connect the battery to the dedicated battery connector, observing correct polarity.

   

   Figure 5: Module shown with an attached 18650 battery holder.
4. TF Card Insertion (Optional):

   For additional storage, insert a TF card into the TF card slot.

2.2 Software Setup

To begin programming and utilizing the module's features, you will need to set up your development environment. The LILYGO TTGO T-Call V1.4 is compatible with the Arduino IDE and other ESP32 development tools.

• Install the ESP32 board package in your Arduino IDE.
• Install necessary libraries for SIM800L, Wi-Fi, Bluetooth, and other peripherals.
• Refer to the official LILYGO GitHub repository for detailed examples and documentation: github.com/Xinyuan-LilyGO/LilyGo-T-Call-SIM800

3. Operating Instructions

3.1 Powering On and Off

• USB Power: Connect the module to a computer or a 5V USB power adapter using a USB cable.
• Battery Power: If an 18650 battery is connected, the module can operate autonomously.
• Power Switch: Use the onboard power switch (if available on your specific variant) to turn the module on or off.

3.2 Wireless Communication

• Wi-Fi: The ESP32 supports 802.11 b/g/n Wi-Fi. Use appropriate libraries and code to connect to Wi-Fi networks, host access points, or perform Wi-Fi scanning.
• Bluetooth: The ESP32 features Bluetooth v4.2 BR/EDR and BLE. This allows for short-range wireless communication with other Bluetooth-enabled devices.
• GSM/GPRS (SIM800L): With a valid Nano SIM card and antenna, the SIM800L module enables cellular communication. This includes sending/receiving SMS, making/receiving calls, and GPRS data transmission.

3.3 GPS Functionality

The module supports GPS for location tracking. Ensure a clear line of sight to the sky for optimal GPS signal reception. Programming examples for GPS data acquisition can be found in the provided GitHub resources.

3.4 Solar Charging

The T-Call V1.4 features a low-power design that supports solar charging for the connected 18650 battery. Connect a compatible solar panel to the designated input for continuous power in outdoor applications.

4. Technical Specifications

Figure 6: Approximate dimensions of the LILYGO TTGO T-Call V1.4 module.

4.1 Pinout Diagram

The module features a comprehensive pinout for various functionalities. Refer to the diagram below for detailed pin assignments, including GPIO, power, and communication interfaces.

Figure 7: Detailed pinout diagram for the LILYGO TTGO T-Call V1.4 module.

5. Maintenance

• Keep the module in a dry environment and avoid exposure to moisture or extreme temperatures.
• Handle the antenna and connectors with care to prevent physical damage.
• If using an 18650 battery, ensure it is charged regularly and stored properly to maintain battery health.
• Periodically check for firmware updates on the official GitHub repository to ensure optimal performance and access to new features.

6. Troubleshooting

• Module Not Powering On: Verify that the USB cable is securely connected and providing power, or that the 18650 battery is charged and correctly inserted. Check the power switch position.
• No Cellular Signal: Ensure the Nano SIM card is correctly inserted and active. Check that the SIM antenna is securely connected and not obstructed. Test in an area with good cellular coverage.
• Wi-Fi/Bluetooth Connectivity Issues: Confirm that the ESP32 firmware is correctly loaded and configured for Wi-Fi/Bluetooth operation. Check for interference from other wireless devices.
• Programming Errors: Double-check your code against examples from the official GitHub repository. Ensure all necessary libraries are installed and the correct board is selected in the Arduino IDE.
• For more in-depth troubleshooting and community support, visit the LILYGO GitHub page: github.com/Xinyuan-LilyGO/LilyGo-T-Call-SIM800

7. Support and Contact

If you have any questions or require further assistance with your LILYGO TTGO T-Call V1.4 module, please feel free to contact LILYGO customer service. We are committed to providing prompt support.

• Online Resources: For comprehensive documentation, code examples, and community forums, visit the official LILYGO GitHub repository: github.com/Xinyuan-LilyGO/LilyGo-T-Call-SIM800
• Product Service: For direct inquiries, please contact LILYGO through the platform where the product was purchased.

8. Warranty Information

Specific warranty details for the LILYGO TTGO T-Call V1.4 module may vary depending on the region and retailer. Please refer to the warranty information provided at the time of purchase or contact LILYGO customer support for further details.