Challenger+ RP2350 NB-IoT

The Challenger+ RP2350 NB-IoT pairs the powerful Raspberry Pi RP2350 dual-core microcontroller with the certified ST87M01-1301 NB-IoT module from STMicroelectronics — giving you global low-power cellular connectivity, integrated GNSS positioning, and the full Challenger/Feather ecosystem in a single compact board. It charges a LiPo battery over USB-C, runs Arduino, MicroPython, and CircuitPython, and fits on a standard breadboard.

Designed for applications that report infrequently over long deployments — asset tracking, smart metering, street lighting, and industrial monitoring.

Key Features

• Powered by RP2350 MCU: At the heart of the Challenger+ RP2350 NB-IoT board lies the RP2350, a powerful micro controller from Raspberry Pi. With its advanced architecture, enhanced processing capabilities, and robust peripheral support, the RP2350 is designed to deliver exceptional performance for a wide range of applications.
• 8MByte Flash: The Challenger+ RP2350 NB-IoT board is equipped with 8MByte Flash memory providing ample storage and memory for complex applications and large datasets. This substantial memory capacity enables the development of more sophisticated and data-intensive projects without compromise.
• ST87M01-1301 module: NB-IoT Cat NB2 — 3GPP Release 15 with extended TBS and 2 HARQ. Bands B1, B3, B5, B8, B20, B28 certified, with broad hardware support for near-worldwide coverage. Up to 159 kbps uplink and 127 kbps downlink.
  • GNSS + A-GNSS — GPS L1 and Galileo in concurrent mode. Assisted GNSS downloads ephemeris data over the NB-IoT link for fast first fix. Dedicated U.FL antenna connector.
  • WiFi positioning — Scans nearby 802.11b access points for indoor location via a third-party geocoding API. No WiFi association required.
  • Full protocol stack — TCP/IP, TLS/DTLS, CoAP, LwM2M, MQTT, HTTP/HTTPS and PDU SMS, all embedded in the module and controlled via AT commands.
• RP2350 microcontroller — Dual Arm Cortex-M33 or RISC-V cores at up to 150 MHz, 520 KB SRAM, 8 MB Flash, 8 MB PSRAM, Arm TrustZone security, and 12 PIO state machines.
• LiPo + USB-C — 1.25 mm Pico-Blade battery connector with integrated charger. Charges from USB-C or the VUSB pin.
• Certified — GCF, RED, and RED-DA cybersecurity certification on the NB-IoT module, simplifying regulatory approval for end products.
• Rich Peripheral Set: Equipped with a comprehensive set of peripherals such as USB, GPIOs, ADCs, DACs, PWM, SPI, I2C, UART, PIO and a heck of a lot more the Challenger+ RP2350 NB-IoT board provides the flexibility needed to interface with numerous sensors, actuators, and modules.
• High Performance and Efficiency: Leveraging the RP2350’s high clock speed, low power consumption, and advanced power management features, the board ensures optimal performance while maintaining energy efficiency, making it suitable for both high-performance and battery-powered applications.

NB-IoT

The ST87M01-1301 is an ultra-compact, fully programmable LTE Cat NB2 module from STMicroelectronics, implementing 3GPP Release 15 and measuring just 10.6 × 12.8 mm in an LGA-51 package.

It supports bands B1, B3, B5, B8, B20, and B28 for certified worldwide coverage, with hardware capability extending across more than 20 additional bands. Peak data rates reach 159 kbps uplink and 127 kbps downlink using extended Transport Block Size and 2 HARQ processes. The module achieves an industry-leading sleep current of 1.2 µA, dropping to 0.5 µA in power-off mode, and supports both PSM and eDRX for maximum battery life in low-duty-cycle applications.

An embedded protocol stack covers TCP/IP, TLS/DTLS, CoAP, LwM2M, MQTT, HTTP/HTTPS, and PDU SMS, allowing complex IoT application logic without an external processor handling connectivity. The -1301 variant adds an integrated GNSS receiver supporting GPS L1 and Galileo in concurrent mode, with Assisted GNSS available over the NB-IoT link for fast first fix. Wi-Fi positioning via nearby 802.11b access point scanning provides an indoor location fallback when satellite signals are unavailable.

The module holds GCF certification across bands B1, B3, B5, B8, B20, and B28, along with RED and RED-DA cybersecurity certification to EN 18031-1/2:2024, significantly reducing the regulatory burden for end-product designers.

Firmware updates are supported both over-the-air via Differential FOTA over LwM2M and locally over UART, making field maintenance straightforward. The module is qualified to industrial grade, operating across the full −40 °C to +85 °C range, and each unit is individually tested and traced to STMicroelectronics’ quality standards.

SIM Card

The board needs a nano SIM card in order to be able to connect to an LTE network and transfer data. Here you can either get it yourself or use our prepaid cards from 1NCE. The IoT pricing of the 1NCE IoT Flat Rate contains 120 months of connectivity services for 150 SEK. It is a one-time-payment only with no hidden costs. 1NCE offers one IoT data plan where all necessary features are included:

• 500 MB data volume with speeds up to 1Mbit/s
• 250 SMS
• SIM card
• Global coverage in 130+ countries (Check if your country is covered here)
• All mobile standards (2G, 3G, 4G, LTE-M, NB-IoT)

The SIM card that we supply is for evaluation only, If you want to take advantage of 1NCE full flexibility with their top-up option and their API’s you should get in touch with them directly here.

Buttons

There are two buttons on the board. The button closest to the USB connector is the reset button. Use it whenever you need to reset the unit. It has exactly the same functionality as the RESET pin. Then there is the BOOT button just next to the reset button. This button must be used in conjunction with the reset button to reset the RP2350 into UF2 mode. Press the BOOT button, then the RESET button for a short moment. Then release the RESET button (while still pressing the BOOT button) and shortly after that release the BOOT button. This will place the board in UF2 mode and show up in the computer as a mass storage device.

USB Type C

In the recent years we have noticed that we are seeing more and more USB Type C cable laying around the lab due to the fact that all new phones and accessories use them. As of yet we haven’t seen any shortage of micro USB cables but we are not getting any new ones any more and old ones do break occasionally. So we decided to go for a USB Type C connector for this board. A bonus of this is that they are quite bit more durable and you don’t have to fiddle with the cable before plugging it in.