The TTGO T-Call is an ESP32 development board that combines a SIM800L GSM/GPRS module for just $11.
Besides Wi-Fi and Bluetooth, you can communicate with this ESP32 board using SMS or phone calls. Additionally, you can connect the ESP32 to the internet using your SIM card data plan. This is great for IoT projects that don’t have access to a nearby router via Wi-Fi.
Where to Buy?
You can get the TTGO T-Call SIM800L ESP32 board for approximately $11 on Banggood or you can get it from other stores:
TTGO T-Call ESP32 Overview
The TTGO T-Call is an ESP32 development board that combines a SIM800L GSM/GPRS module for just $11.
This allows you to connect your ESP32 to the internet using your SIM card data plan, or communicate with the board vis SMS or phone calls. This can be very handy for projects in remote locations.
2G Network
Important: The SIM800L works on 2G networks, so it will only work in your country, if 2G networks are available. Check if you have 2G network in your country, otherwise it won’t work.
Nano SIM Card
Please note that this board requires a SIM card with some data plan. This can be expensive in some countries, so it might be cost prohibitive depending on how much you can get a data plan for in your country.
Where we live (Portugal), we can get a SIM card with data plan, calls and SMS (enough for ESP32 projects) for approximately $12.
Please note that this board only supports nano SIM cards.
USB-C
The TTGO T-Call uses a USB-C slot for power and programming (via CP2104).
The USB-C cable is not included in the package, so you might consider getting one, when you buy the board.
Power Supply
The TTGO T-Call SIM800L can be powered via USB-C cable or you can use the 2-pin JST header for the 3.7V lithium battery. The battery connector is included with the package. You’ll also get an antenna and header pins.
We had some signal strength issues with the antenna that came with the package. So, we used one of the following antennas, and all the connection problems were solved.
TTGO T-Call Sim800L Pinout
When you get your TTGO T-Call ESP32 board, it comes with header pins that you can solder to the board to access the ESP32 GPIOs to connect peripherals like sensors or outputs.
This allows you to control outputs or monitoring sensors just by sending SMS or making phone calls to your ESP32.
This can be a perfect board to put in a remote location to control an output when you send an SMS or to get sensor readings in your smartphone.
The following figure shows the TTGO T-Call SIM800L Pinout:
Programming the TTGO T-Call SIM800L Board
There are several ways to program your board: using Arduino IDE, MicroPython or ESP-IDF. The TTGO T-Call SIM800L GitHub page suggests the following examples to get started:
- Loboris Micropython: examples/MicroPython_LoBo
- Arduino + TinyGSM library: examples/Arduino_TinyGSM
- Arduino + SIM800 library: examples/Arduino_sim800
- Arduino OTA update over GSM: examples/Arduino_GSM_OTA
- ESP-IDF: https://github.com/espressif/esp-idf/tree/master/examples/protocols/pppos_client
ESP32 SIM800L Publish Data to Cloud without Wi-Fi
This project shows how to connect the TTGO T-Call ESP32 SIM800L board to the Internet using a SIM card data plan and publish data to the cloud without using Wi-Fi. We’ll use Arduino IDE to program this board. Read project page: ESP32 Publish Data to Cloud without Wi-Fi (TTGO T-Call ESP32 SIM800L).
ESP32 SIM800L Send Text Messages
This project shows how to set up an SMS notification system to send text messages when sensor readings reach a certain threshold value. Read project page: ESP32 SIM800L: Send Text Messages (SMS Alert) with Sensor Readings.
TTGO T-Call SIM800L Board Specifications
Lastly, here’s a list of the TTGO T-Call SIM800L ESP32 Board specifications:
- Chipset: ESP32 240MHz Xtensa® dual-core 32-bit LX6 microprocessor
- FLASH: QSPI flash 4MB / PSRAM 8MB
- SRAM: 520 kB SRAM
- Connectivity:
- WiFi 4 802.11 b/g/n (2.4 GHz) up to 150 Mbps
- Bluetooth 4.2 Classic + Bluetooth Low Energy (BLE)
- 2G GSM/GPRS via SIMcom SIM800L module + Nano SIM card slot
- Reset Button
- USB to TTL CP2104
- USB-C port for power and programming
- Interface: pin headers with UART, SPI, SDIO, I2C, PWM, PWM, I2S, IRGPIO, capacitor touch sensor, ADC, DAC
- Power supply:
- USB-C port: 5V 1A
- JST header: 3.7V Lithium battery (500 mA charging current)
For more information: https://github.com/Xinyuan-LilyGO/TTGO-T-Call
Wrapping Up
The TTGO T-Call SIM800L ESP32 board adds celular connectivity to your projects. This means that besides Wi-Fi and Bluetooth, you can also communicate with your board using SMS, phone calls or connect to the internet using your SIM card data plan.
This board is great for IoT projects in remote locations because you can send an SMS to your ESP32 to request sensor data, receive SMS notifications on your smartphone when a sensor reading is above a certain threshold, send SMS to control outputs, and much more!
Additionally, having an ESP32 that doesn’t need to be configured to a router to connect to the internet (because it uses the SIM card data plan) is great for many projects.
We hope you’ve found this overview useful. We’ll be posting more tutorials about this board at the Random Nerd Tutorials blog soon. So, stay tuned.
Lastly, if you don’t have an TTGO T-Call SIM800L ESP32 board, take a look at the following links.
You might also like the following articles:
- 10 IoT Development Boards You Need to Get
- $7 ESP32-CAM with OV2640 Camera
- ESP32 Built-in OLED Board (Wemos Lolin32): Overview and Getting Started
Thanks for reading.
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