1. Introduction
The LILYGO T-SIM-A7670 series is a versatile development board integrating an ESP32-WROVER-B microcontroller with a SIMCOM A7670 LTE Cat1 module. This board offers robust wireless communication capabilities including 4G LTE, GSM, GPRS, and EDGE, along with optional GPS functionality depending on the specific A7670 variant. It is designed for IoT applications requiring reliable cellular connectivity, location tracking, and general-purpose computing.
2. Setup
This section guides you through the initial setup of your LILYGO T-SIM-A7670 development board.
2.1 Package Contents
The standard package for the T-SIM-A7670E option typically includes:
- 1 x T-SIM-A7670E module
- 1 x LTE antenna
- 1 x Power cord
- 2 x Pin headers
2.2 Pinout Diagram
Understanding the pinout is crucial for connecting peripherals and programming the board. Refer to the detailed pinout diagram below:
2.3 Hardware Connections
- Attach LTE Antenna: Carefully connect the FPC LTE antenna to the designated U.FL connector on the board. Ensure a secure connection for optimal signal reception.
- Insert TF Card (Optional): If your application requires local storage, insert a TF (MicroSD) card into the TF card slot.
- Insert Nano SIM Card: For cellular communication, insert a Nano SIM card into the SIM card slot. Ensure it is correctly oriented. The A7670 module supports 2G/3G/4G networks.
- Powering the Board: The board can be powered via USB-C, a 18650 battery, or a solar panel.
- USB-C: Connect a USB-C cable to the board and a power source (e.g., computer, USB charger).
- 18650 Battery: Insert a charged 18650 battery into the battery holder on the back of the board.
- Solar Panel: Connect a compatible solar panel to the designated solar input pins for continuous power in outdoor applications.
3. Operating Instructions
The LILYGO T-SIM-A7670 board is a development platform. Operation primarily involves programming the ESP32 microcontroller to utilize the integrated modules.
3.1 Programming the ESP32
The ESP32-WROVER-B can be programmed using various development environments, such as the Arduino IDE, ESP-IDF, or MicroPython. Connect the board to your computer via the USB-C port. This port provides both power and a serial interface for uploading code and debugging.
3.2 Cellular Communication (A7670 Module)
The SIMCOM A7670 module supports LTE Cat1, GSM, GPRS, and EDGE. You will need to use AT commands or a suitable library (e.g., TinyGSM) within your ESP32 code to control the A7670 module for tasks such as:
- Connecting to cellular networks
- Sending and receiving SMS messages
- Making and receiving calls (voice functionality)
- Establishing data connections (TCP/IP, HTTP/HTTPS)
3.3 GPS Functionality (for GPS-enabled variants)
If you have an A7670E with GPS or A7670G with GPS variant, the module can acquire location data. Your ESP32 code will interact with the A7670 module to request and parse NMEA sentences for GPS coordinates.
3.4 Wi-Fi and Bluetooth
The integrated ESP32-WROVER-B provides Wi-Fi (802.11 b/g/n) and Bluetooth (v4.2 BR/EDR and BLE) connectivity, allowing for local network communication or short-range device pairing.
4. Maintenance
- Keep Dry: Avoid exposing the board to moisture or liquids.
- Clean Gently: Use a soft, dry brush or compressed air to remove dust. Do not use harsh chemicals.
- Handle with Care: Electronic components are sensitive. Avoid dropping or subjecting the board to physical shock.
- Firmware Updates: Regularly check for updated firmware or libraries for the ESP32 and A7670 module to ensure optimal performance and security.
5. Troubleshooting
- Board not powering on: Ensure the power source (USB-C, battery, solar) is correctly connected and providing sufficient voltage. Check the power switch if present.
- ESP32 not detected by computer: Verify the USB-C cable is functional and properly connected. Install necessary USB drivers for the ESP32 if prompted by your operating system.
- No cellular network connection:
- Ensure the Nano SIM card is correctly inserted and activated with a valid data plan.
- Check that the LTE antenna is securely connected.
- Verify that the A7670 module is powered on and initialized correctly in your code.
- Confirm that the module variant (A7670E, A7670SA, A7670G) supports the frequency bands in your region (refer to specifications).
- GPS not acquiring signal: Ensure you are using a GPS-enabled variant of the A7670 module. GPS signal acquisition can take time and requires an open sky view.
- Code upload issues: Check your IDE settings for correct board selection and serial port. Ensure no other applications are using the serial port.
6. Specifications
6.1 General Specifications
| Feature | T-A7670SA | T-A7670E |
|---|---|---|
| MCU | ESP32 | ESP32 |
| LTE & GSM Module | A7670SA | A7670E |
| TF Card Function | ✓ | ✓ |
| ESP32 Clock Frequency | 240MHz | 240MHz |
| Flash | 4MB | 4MB |
| PSRAM | 4MB | 4MB |
| Wireless Communication Protocols | Wi-Fi: 802.11 b/g/n, Bluetooth: v4.2 BR/EDR and BLE | |
| Serial Bus Communication Protocols | I2C, SPI, UART, SDIO, I2S, CAN | |
| A7670 Series Composition | LGA | |
| Usage Region | South America, New Zealand, Australia | Europe, Middle East, Africa, South Korea, Thailand |
| Dimensions (mm) | 24.0 * 24.0 * 2.3 | |
| LTE (Mbps) | 10(DL)/5(UL) | |
| GPRS/EDGE (Kbps) | 236.8(DL)/236.8(UL) | |
| LTE Power Consumption (mA) | 3.8 | |
| GSM Power Consumption (mA) | 3.5 | |
| Supported Software Network Protocols | TCP/IP/IPV4/IPV6/DNS/Multi-PDP/FTP/FTPS/HTTP/HTTPS | |
| Android RIL Support | Android 5.0/6.0/7.0/8.0/9.0 | |
| USB Driver Support | Microsoft Windows 7/8/10, Linux, Android | |
| Input Voltage Range (V) | 3.4 ~ 4.2 | |
| SIM Card Voltage (V) | 1.8V/3.0V | |
| Certifications | RoHS\REACH\RCM\CE(RED)\OCD(Anatel)\FCC | RoHS\REACH\CE(RED) |
6.2 Frequency Band Comparison
The A7670SA and A7670E modules support different frequency bands, which determines their compatibility with regional cellular networks. Please refer to the table below to ensure the selected module variant is suitable for your intended deployment region.
| Band Type | Frequency | A7670SA Support | A7670E Support |
|---|---|---|---|
| GSM | 850MHz | ✓ | ✓ |
| 900MHz | ✓ | ✓ | |
| 1800MHz | ✓ | ✓ | |
| 1900MHz | ✓ | ✓ | |
| LTE-FDD | FDD B1 | ✓ | ✓ |
| FDD B2 | ✓ | ||
| FDD B3 | ✓ | ✓ | |
| FDD B4 | ✓ | ||
| FDD B5 | ✓ | ✓ | |
| FDD B7 | ✓ | ✓ | |
| FDD B8 | ✓ | ✓ | |
| FDD B20 | ✓ | ✓ | |
| FDD B28 | ✓ | ||
| FDD B66 | ✓ | ||
| GNSS | BeiDou | N/A | N/A |
| GPS | N/A | N/A | |
| Glonass | N/A | N/A | |
| LTE-TDD | N/A | N/A |
7. User Tips
- GPS and 4G Support: The LILYGO T-SIM-A7670 series explicitly supports 4G LTE Cat1 communication. For GPS functionality, ensure you select a module variant that includes GPS (e.g., A7670E with GPS, A7670G with GPS) as indicated in the product description.
- Power Management: When using battery power, consider implementing deep sleep modes in your ESP32 code to maximize battery life, especially for remote or long-term deployments.
- Antenna Placement: For optimal cellular and GPS performance, ensure the FPC antenna is placed in an open area, away from metal obstructions or other electronic components that might cause interference.
8. Warranty and Support
For technical support, documentation, and community resources, please refer to the official LILYGO website or relevant online forums for ESP32 and SIMCOM A7670 modules. The manufacturer typically provides support for hardware defects within a specified warranty period. Please retain your proof of purchase for any warranty claims.
