Adafruit Feather RP2040 RFM69 Packet Radio – 868 or 915MHz – RadioFruit and STEMMA QT

This is the Adafruit Feather RP2040 RFM69 Packet Radio (868 or 915 MHz). We call these RadioFruits, our take on a microcontroller with packet radio transceiver with built-in USB and battery charging. It’s an Adafruit Feather RP2040 with an RFM69HCW 900MHz radio module cooked in! Great for making wireless networks that are more flexible than Bluetooth LE and without the high power requirements of WiFi.

Feather is the development board specification from Adafruit, and like its namesake, it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. We have other boards in the Feather family, check’em out here.

It’s kinda like we took our RP2040 Feather and RFM69 900MHz breakout board and glued them together. You get all the pins for use on the Feather, the Lipoly battery support, USB C power/data, onboard NeoPixel, 8MB of FLASH for storing code and files, and then with the 8 unused pins, we wired up all the DIO pins on the RFM module. There’s even room left over for a STEMMA QT connector and a uFL connector for connecting larger antennas.

This is the 900 MHz RFM69 packet radio version, which can be used for either 868MHz or 915MHz transmission/reception – the exact radio frequency is determined when you load the software since it can be tuned around dynamically. Despite calling it a ‘packet’ radio (and it does send packets of data) the RFM69 can also be used for non-packetized radio transmission and reception.

At the Feather’s heart is an RP2040 chip, clocked at 133 MHz and at 3.3V logic, the same one used in the Raspberry Pi Pico. This chip has a whopping 8MB of onboard QSPI FLASH and 264K of RAM! This makes it great for making wireless sensor nodes that can send to each other without a lot of software configuration.

To make it easy to use for portable projects, we added a connector for any of our 3.7V Lithium polymer batteries and built in battery charging. You don’t need a battery, it will run just fine straight from the USB Type C connector. But, if you do have a battery, you can take it on the go, and then plug in the USB to recharge. The Feather will automatically switch over to USB power when its available.

Features

• Measures 52.2mm x 23.0mm x 7.3mm / 2.1′ x 0.9′ x 0.3′ without headers soldered in
• Light as a (large?) feather – 6 grams
• RP2040 32-bit Cortex M0+ dual core running at ~133 MHz @ 3.3V logic and power
• 264 KB RAM
• 8 MB SPI FLASH chip for storing files and CircuitPython/MicroPython code storage. No EEPROM
• Tons of GPIO! 21 x GPIO pins with the following capabilities:
  • Four 12-bit ADCs (one more than Pico)
  • Two I2C, Two SPI, and two UART peripherals, we label one for the ‘main’ interface in standard Feather locations
  • 16 x PWM outputs – for servos, LEDs, etc
• Built-in 200mA+ lipoly charger with charging status indicator LED
• Pin #13 red LED for general-purpose blinking
• RGB NeoPixel for full-colour indication.
• On-board STEMMA QT connector that lets you quickly connect any Qwiic, STEMMA QT or Grove I2C devices with no soldering!
• Both the Reset button and Bootloader select button for quick restarts (no unplugging-replugging to relaunch code)
• USB Type C connector lets you access built-in ROM USB bootloader and serial port debugging
• 3.3V Power/enable pin
• 4 mounting holes
• 12 MHz crystal for perfect timing.
• 3.3V regulator with 500mA peak current output

We squished all the parts on our Feather RP2040 over towards the USB port to make some room on the end. This Feather RP2040 Packet Radio uses the extra space left over to add an RFM69HCW high power 868/915 MHz radio module. These radios are not good for transmitting audio or video, but they do work quite well for small data packet transmission when you need more range than 2.4 GHz (BT, BLE, WiFi, ZigBee).

Specifications

• SX1231-based module with SPI interface
• +13 to +20 dBm up to 100 mW Power Output Capability (power output selectable in software)
• 50mA (+13 dBm) to 150mA (+20dBm) current draw for transmissions, ~30mA during active radio listening.
• Range of approx. 500 meters, depending on obstructions, frequency, antenna and power output
• Create multipoint networks with individual node addresses
• Encrypted packet engine with AES-128
• Packet radio with ready-to-go Arduino & CircuitPython libraries
• Uses the license-free ISM band: ‘European ISM’ @ 868MHz or ‘American ISM’ @ 915MHz
• Simple wire antenna can be soldered into a solder pad, there’s also a uFL connector that can be used with uFL-to-SMA adapters for attaching bigger antennas.
• Product Dimensions: 52.2mm x 23.0mm x 7.3mm
• Product Weight: 6.0g

Our initial tests with default library settings indicate they can go at least 500 meters line of sight using simple wire antennas, probably up to 5Km with directional antennas and settings tweakings

Comes fully assembled and tested, we also toss in some headers so you can solder it in and plug it into a solderless breadboard. You will need to cut and solder on a small piece of wire (any solid or stranded core is fine) in order to create your antenna. or use a uFL connector and SMA 900MHz antenna. Lipoly battery and USB cable are not included, but we do have lots of options in the shop if you’d like!

Resources

• Product Wiki