Conexio Stratus Pro nRF9151 low-power IoT development kit supports LTE-M/NB-IoT, DECT NR+, GPS, and more

Conexio Stratus Pro nRF9151 is an IoT development kit based on Nordic Semi nRF9151 system-in-package (SiP) with LTE-M/NB-IoT, DECT NR+, and GNSS connectivity designed for battery-powered cellular-connected products such as asset trackers, environmental monitors, smart meters, and industrial automation devices.

It’s offered with the “Stratus Pro Expansion Dock” allowing users to add WiFi 6 through an nRF7002 expansion board and various other modules via Grove, Qwiic, MikroBus, and Seeed Studio’s XIAO connectors or sockets. It’s an update to the original Conexio Stratus Pro based on nRF9161 introduced last June with a very similar feature set. Let’s have a deeper look to find out any potential differences between the two versions of the devkit.

Conexio Stratus Pro nRF9151 specifications (with changes highlighted in bold or ~~strikethrough~~):

System-in-package – Nordic Semi nRF9151 SiP
- MCU – Arm Cortex-M33 clocked at 64 MHz with 1 MB Flash pre-programmed MCUBoot bootloader, 256 KB RAM
- Modem
  - Transceiver and baseband
  - 3GPP LTE release 14 LTE-M/NB-IoT support
  - DECT NR+ ready. DECT NR+ mesh network is designed for long-range low-power applications that work at 1.9 GHz and support up to one million nodes
  - GPS/GNSS receiver
  - RF Transceiver for global coverage supporting bands: B1, B2, B3, B4, B5, B8, B12, B13, B17, B18, B19, B20, B25, B26, B28, B65 (new), B66, and B85 (new)
Storage – 16 KBit I2C EEPROM memory (24CW160T)
SIM support – 4FF Nano SIM, optional eSIM, or software SIM
Antennas
- 1x U.FL connector for LTE-M/NB-IoT antenna
- 1x U.FL connector for passive GPS antenna
Cellular Data
- 500 MB of cellular data
- 250 SMS messages
- Valid for 10 years, can be reloaded or moved to a new plan
- Service available in 100+ countries (LTE + NB-IoT)
USB – 1x USB Type-C port for USB-to-Serial, DFU, application firmware programming and debugging, battery charging
Sensors
- STMicro LIS2DH 3-axis accelerometer
- Battery fuel gauge (enabled by nPM1300 PMIC)
- Temperature sensor (on-chip nRF9151)
Expansion
- Feather-compatible header with 28 programmable GPIO pins
- QWIIC connector for external peripherals such as a small camera for ML applications
Debugging
- Supports J-Link and CMSIS-DAP-based programmers
- 10-pin (1.27 mm pitch) mini SWD/JTAG pin connector
Misc
- 2x push buttons (1x reset, 1x programmable)
- Programmable LED
Power Management
- Voltage Range – 1.8 to 5.5V
- 2-pin JST connector for LiPo battery
- Output voltages (via headers) – 1.8V, 3.3V, 5V (VUSB), VBAT
- SPDT slide switch for turning Stratus Pro on or off
- Quiescent current of entire board < 9 μA
- PMIC – Nordic nPM1300
  - 800 mA battery charger
  - Dual 200 mA buck DC/DC regulator
- ~~Charging IC – Texas Instruments BQ25185~~
  - ~~Charge inputs: 3V to 18V~~
  - ~~Supports Li-ion, Li-Poly, and LiFePO4 battery chemistries~~
- Energy harvester IC
  - Onboard battery charger with solar energy harvester
  - Continuous Charge Current up to 1A
  - Input supply voltage – 4.4-6V
  - Supports battery types Li-ion, Li-Poly, and LiFePO4 chemistries
  - Automatic charge current adjustment based on the output capability of the input power supply
Dimensions – 66.04 x 25.40 mm

There do not seem to be any differences between the two development kits apart from the nRF9151 module being smaller than nRF9161, and potentially a temperature sensor on the nRF9151 and a different charging IC. So I asked Conexio, and they replied both devkits were essentially the same, but the nRF9151 devkit is cheaper:

Module and functionality wise, there is no difference except as you mentioned, nRF9151 has smaller footprint than nRF9161.

Stratus Pro nRF9151 is also offered at a better pricing than the previous one.

The rest are exactly the same.

For that reason, the company also told me that they are moving from the Conexio Stratus Pro nRF9161 to nRF9151 as a long-term support device. That also means software support is the same, you can use the same documentation and firmware. The latter has been improved in the last few months with an upgraded Datacake sample pushing SHT4x, battery, and accelerometer data to the cloud, support for DPS310, BME280, and SHT3XD sensors, battery charging over USB with the nPM1300 PMIC, Wi-Fi scanning capabilities using the nRF7002EB, and remote battery monitoring via cellular modem.

Conexio Stratus Pro nRF9151 Expansion Dock — Stratus Pro Expansion board with MikroBus Weather Click, nRF7002EB, and XIAO ESP32C3 modules

While the Conexio Stratus Pro nRF9151 can be used as a standalone board thanks to the open CPU core allowing users to run their own application on the nRF9151, the company also provides the Stratus Pro Expansion board with the following features:

Compatible with Stratus Pro nRF9161 and nRF9151
Optional support for Bluetooth 5, ZigBee, Thread, Matter, and/or Wi-Fi 6 with
- Socket for Seeed Studio XIAO series module
- Connector for Nordic Semiconductor’s nRF7002 EB
I/O expansion
- 2x QWIIC connectors
- 2x Grove sockets
- mikroBUS socket for MikroElektronika Click boards

The Stratus Pro nRF9151 development kit can be pre-ordered now for $69, and the expansion dock adds another $25 with shipping scheduled before the end of the year. Those are samples from a small production run of 60 units, and only 9 pieces are left at the time of writing. It’s unclear when mass production will start, and the $69 is a “super early bird” offer for pre-orders only. A few more details may be found on the product page.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.