Design ESP32 LoRa GPS Tracker Applications with TTGO T-Beam Board

Orange Pi Development Boards

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.

ESP32 LoRa GPS Tracker
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TTGO T-Beam board specifications:

  • SoC – Espressif ESP32 dual core Xtensa LX6 processor with WiFi and Bluetooth
  • Memory – PSRAM
  • Storage – 4MB SPI flash
  • Connectivity
    • 802.11 b/g/n WiFi up to 150 Mbps +  Bluetooth 4.2 Classic and LE with “3D antenna” soldered on PCB
    • LoRa
      • 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
TTGO T-Beam Pinout
Click to Enlarge

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.

LoRa GPS Tracker with 18650 Battery HolderAgain 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.

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PuceBaboon
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It’s kinda ironic that Region-3 (Asia) is the worst supported in terms of available products when nearly all of the boards are produced here. 🙁

Anyone found a source of 920MHz modules that -don’t- cost an arm and a leg yet?

TLS
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TLS

If the modules are done right, they should be software configurable for the frequency. The issue is that the board makers might not supply the right antenna, so the range might be reduced, in some cases significantly.
LoRA is really quite an annoying standard in the sense that almost none of the board makers seems to undertand that it’s not a fixed frequency thing, unlike say Z-Wave, where you have to get a specific SKU for a region/frequency.