SB Components Raspberry Pi Pico LoRa Expansion – A Review

I’ve been toying with a Raspberry Pi Pico board for quite some time. Some people say it’s an Arduino Nano board running MicroPython. This is, of course, an understatement, as the Pico is much more than that. It can even be programmed using the Arduino IDE.

While I was playing with the Pico, the SB Components Pico LoRa Expansion landed on my desk with all its pomp and splendor. The onboard shiny SMA connector and LoRa module, the voltage level shifter IC along with a USB-to-UART chip and a small 1.14” color TFT display give the board a very elegant aspect.

More Powerful While Consuming Less

The LoRa module is an E22-900T22S from EByte. This is a wireless serial port module (UART) based on the new-generation Semtech SX1262 chip. The module can deliver transmission power of up to 22 dBm (158 mW) in the 850.125 MHz to 930.125 MHz ISM band (). This should be good for a range of up to 5 km (line-of-sight, LoS). The module uses LoRa spread spectrum technology and has longer range than the popular SX1278 while consuming less power.

The Two Operating Modes of the SB Components Pico LoRa Expansion

The LoRa module on the Pico LoRa Expansion Board can either be connected to a USB port or to the Pico Board by setting two jumpers (Device Selection). Another set of jumpers (Mode Selection) controls the working-mode pins M0 and M1 of the LoRa module.

Setting the board in action is simple. Connect the USB cable and then launch a serial terminal, even the Arduino IDE’s Serial Monitor will work. Set its speed to 9,600 baud (8N1), write something and send it. Blinking of the onboard Tx and Rx LEDs indicates that the characters are transmitted.

 

A small program is preloaded in the Pico to display the data coming from the remote LoRa station on the TFT display. However, for this to work, the Device Selection jumpers must be changed over to Pico and both M0 and M1 must be shorted to GND.

Online Resources

A list of how the TFT screen and LoRa module connect to the Pico is available on the board’s Wiki page. There, too, you will find information on how to get started together with a link to the repository on GitHub. The repository contains two Python demo scripts and a Windows utility to configure the LoRa module. This program can also be used for sending and receiving data in USB mode.

USB LoRa has three programming pins: Aux, M0 and M1. While Aux is normally connected to 3.3 V, the M0 and M1 pins enable different options to operate the LoRa device. Unless you have a fair idea about these pins, using the module in this mode in the most effective way is a bit difficult. Some common settings for e.g. one-to-one LoRa communication is having the same channel frequency, air rates and a 4-byte ID for the different LoRa modules. To achieve this, one needs to put the LoRa module first in programming mode (M0 shorted, M1 open). By default, the module is set to broadcast mode.
 

 

Summarizing

The Raspberry Pi Pico LoRa Expansion is a nice way to get started with LoRa, MicroPython and the Raspberry Pi Pico. However, measuring 90 mm by 60 mm, it is rather big for such small functionality. As an example, the TTGO LoRa32 board with OLED display is much smaller, packs more functionality while costing less.

Nevertheless, the fact that the Raspberry Pi Pico can be programmed in MicroPython will please many potential users. The onboard color TFT display is a big boost up as it makes displaying received data and other information easy. The GPIO pins of the Pico are easily accessible on the board.

Note that there also exists a 433-MHz version of the SB Components Raspberry Pi Pico LoRa Expansion.