Bluetooth 5.0 has two main new features: high speed (2Mbps) and long-range. But as we’ve seen in our nRF52840 vs nRF52832 vs nRF52810 comparison is that only nRF52840 supports Bluetooth 5.x long range.
Bluetooth 5 long range is achieved with two new lower bit rates of 500 kbps and 125 kbps. So what do you do if you’d like a longer range and keep using the higher bit rates? You add a power amplifier and LNA to your board, and that’s exactly what Nikolaj (RFCat) did with RFCat N32 board based on Nordic Semi nRF52832 wireless SoC.
RFCat N32 board specifications:
- Wireless module – Meshtek-H52 Smart Mesh Module with integrated PCB antenna based on Nordic Semi nRF52832 Arm Cortex-M4F Bluetooth 5-ready SoC (See datasheet)
- Skyworks RFX2401C PA &LNA with 18.9dBm TX gain and 11dBm RX gain
- USB – 1x USB-C port for power, programming and debugging via CP2102N USB to UART bridge
- I/Os – 2x 13-pin 2.54mm pitch headers with 21x GPIOs, 7x ADC, I2C, SPI, GND, 3.3V, and 5V also accessible as solder pads on the bottom of the board to use it as a module on another PCB.
- Misc – Reset button, 2x user buttons also used for DFU and OTA, and 2 LEDs
- Debugging – Serial via USB-C port, and 4-pin SWD header
- Power Supply – 5V via USB-C or 5V pin on header; 3.3V/300mA LDO
- Dimensions – 56 x 25 mm including module’s PCB antenna
Nikolaj explains an nRF52832 board usually has a 2.5mW Tx Power, an nRF52840 board around 6.3mW, so at 77.6 mW, the power amplifier provides around 30 times higher transmit power than traditional boards. Of course, power consumption will be much higher, so it’s not suitable for battery-operated devices unless they transmit very infrequently.
The board is pre-loaded with Adafruit NRF52 bootloader supporting OTA, FreeRTOS, and Arduino. Source code and samples are available on Github. The Arduino library is based on Adafruit nRF52 Arduino Core and for some reason, only shared as a zip file (rfcat.zip in the Github repo).
Nikolaj uploaded a video providing an overview of the board, and comparing to a regular nRF52832 module without a power amplifier. The regular board loses connectivity about 14 meters away, while RFCat N32 can still transmit at around 115KB/s at that distance, and is still working at 90KB/s at 24 meters from the source in an indoor environment.
RFCat N32 board can be purchased on Tindie for $29, where you’ll also find a datasheet with extra details.