TTGO introduced a small ESP32 LoRa board with OLED display last year that is still selling for around $14 shipped. But the company is now back with a similar board called TTGO T-Beam that does without the display, but adds GPS support, and a 18650 battery holder, so it should be ideally suited for all sorts of LoRa GPS tracking applications.
TTGO T-Beam board specifications:
- SoC – Espressif ESP32 dual core Xtensa LX6 processor with WiFi and Bluetooth
- Memory – PSRAM
- Storage – 4MB SPI flash
- 802.11 b/g/n WiFi up to 150 Mbps + Bluetooth 4.2 Classic and LE with “3D antenna” soldered on PCB
- 433, 868, and 915 MHz versions with SMA antenna
- Transmit current – 120 mA @ +20dBm; 90 mA @ +17dBm; 29mA @ +13dBm
- Receive sensitivity
- -139dBm with LoRa & 62.5Khz & SF=12 & 146bps
- -136dBm with LoRa & 125Khz & SF=12 & 293bps
- -118dBm with LoRa & 125Khz & SF=6 & 9380bps
- -123dBm with FSK & 5Khz & 1.2Kbps
- Location – Ublox NEO-6M GPS module with ceramic antenna
- Expansion – 26-pin header (unpopulated) with GPIO, ADC, VP/VN, DAC, Touch, SPI, I2C, UART, 2x “LoRa” pin, and power signals (5V/3.3V/GND)
- Debugging / Programming – micro USB port with CP2104 chip
- Misc – Two buttons (power and GPIO39)
- Power Supply – 18650 battery (not supplied)
- Dimensions – N/A
The board can be programming with the Arduino IDE, and you’ll find code samples on Github showing how to receive and send data over LoRa, and get GPS data.
TTGO T-Beam is sold on Banggood for $30.89 and ships with a LoRa antenna, and two unsoldered headers as shown below. The GPS antenna is already attached to the boards, and the WiFI/Bt antenna is soldered to the board, so all you need is a 18650 battery, and some good idea to implement. The board is also sold on Aliexpress’ LilyGO store, but for around $36 shipped.
Again there’s no specific version for frequencies like AS923 (Asia), KR920-923 (Korea), or IN865-867 (India), but I’ve recently realized those work with the 915 MHz (first two) and 868 Mhz (last one), and just need a specific firmware, which as I understand it needs to be flashed by the manufacturer. For example, I’m soon expecting a RAK811 LoRa tracker board, and RAK Wireless told me they’d send the 915 MHz version with firmware for AS923. The same is true for gateways. I just don’t know if this is a possibly for TTGO T-Beam board.