Nothing shows the increasing capability, and the drop in price, of computing than the ESP8266 and ESP32 from Espressif. For those of us that lived and worked through the early years, the idea that a single chip device can now connect to Wi-Fi and the Internet is still somewhat akin to magic.
It’s not quite that simple, at least not yet, when it comes things. There the standards war for low-powered, long-range, but low-bandwidth wireless connectivity is still to come, with the three competitors; NB-IoT, Sigfox, and LoRaWAN squaring off in their respective corners. The fourth, known as Wi-Fi HaLow, is still trying to find the ring, let alone its corner.
For me, the measure of how the early stages of the war is going can be weighed and measured. It exists in stacks of boards in a box beside my desk, hardware that has—one way or another—made its way into my mailbag.
Still relatively expensive in this day and age of “almost free” computing, one thing I’m looking out for is how the pricing of long-range wireless capable boards supporting the different competitors are trending. Which is where the new TTGO T-Beam “tracker” board comes into the picture.
The board is built around a dual-core ESP32 chip, with 4MB of SPI flash onboard, providing both Wi-Fi and Bluetooth LE via a “3D antenna” on the PCB.
The board’s LoRa support comes in three different variants, operating at 433MHz, 868MHz, and 915MHz depending on region, with an included SMA antenna. While location tracking is provided by the onboard u-blox NEO-6M GPS module with ceramic antenna.
The TTGO T-Beam offers 26-pin headers with GPIO, ADC, VP/VN, DAC, touch, SPI, I2C, UART, 2×“LoRa” pin, and power signals (5V/3.3V/GND). There are also two buttons on the board—one is for power, but the second connected to the GPIO39 pin of the ESP32.
The board can be programmed using the Arduino development environment, and the example code shows you how to both send and receive data via LoRa.
Flipping the board over there is a battery holder for a 18650 Li-Ion cell, and while a 18650 sort of looks like a “standard” AA battery, it’s significantly different. So don’t make the mistake of substituting in the more common AA battery to try and power the board. They’re not quite the same size, but I’ve seen people attempt this substitution nonetheless.
The TTGO T-Beam is available on Banggood for $30.89 with free shipping, or on AliExpress for $33.70 with $2.55 shipping to the United States. For a full featured battery-powered LoRa board, with GPS, that’s pretty reasonable.