So looking closely at these to gain some insight as to future PCB plans and New devices.
WARNING , This is TLDR… Thinking out loud ! I have to make a presentation for a discussion about What could BE!
Key Advantages of the nRF52840 Xiao Sense:
- IMU Interrupt Support
- The nRF52840 Xiao Sense has the interrupt pin from the IMU wired, enabling event-driven functionality.
- The Xiao MG24 does not have the interrupt pin wired, meaning you’d have to poll the IMU sensor for updates, which increases power consumption and reduces responsiveness for applications like motion detection.
- Lower Power Consumption in Sleep Mode
- The nRF52840 boasts 4-5 µA sleep current, making it highly efficient for battery-powered devices.
- The MG24 datasheet may not explicitly highlight its sleep current, but Zigbee and Thread MCUs often have slightly higher idle power due to their radio protocols.
- Mature Ecosystem
- The nRF52840 has a well-established development ecosystem, with extensive support for Arduino IDE, Zephyr RTOS, and Nordic’s SDK (nRF Connect).
- The MG24 is newer and primarily geared toward Zigbee/Thread applications, with fewer general-purpose libraries and community resources at this time.
- Proven BLE Performance
- The nRF52840 offers robust Bluetooth 5.0 support with proven reliability in real-world projects.
- The MG24 also supports Bluetooth but emphasizes Zigbee and Thread protocols, which may not be necessary for your application.
- Peripheral Support
- The nRF52840 features excellent peripheral integration, including PDM for microphones, I2S, and USB support, making it versatile for a wide range of projects.
- The MG24 is slightly more specialized toward Zigbee/Thread, potentially limiting flexibility for non-radio-centric applications.
- Power and Efficiency for BLE Applications
- If BLE performance and power efficiency are critical, the nRF52840 is a known performer with optimized power modes for BLE operations.
- The MG24 might not achieve similar efficiency for BLE-focused projects since it is optimized for mesh protocols.
- Community and Documentation
- The nRF52840 has comprehensive community support, detailed guides, and robust Nordic documentation.
- As a newer product, the MG24 has a smaller community and less documentation for broader use cases beyond Zigbee/Thread.
Other Considerations:
-
If Zigbee/Thread are a Requirement:
The MG24 is designed for these protocols and may offer better native support for Zigbee networks. However, you’ve primarily worked on BLE and IMU-based projects, so the nRF52840 seems better aligned with your expertise and needs. -
Interrupts are Crucial for Low Power Applications:
The absence of an interrupt pin for the IMU on the MG24 Sense is a critical limitation for motion detection or event-driven designs, as it forces the MCU to poll the IMU regularly, negating its power-saving benefits.
Conclusion:
The nRF52840 Xiao Sense appears to be the better option for your needs:
- Better low-power performance.
- Full IMU functionality with interrupt support.
- Versatility across BLE and IMU-driven applications.
- Mature ecosystem and greater flexibility for general-purpose projects.
The MG24 Xiao Sense may only be preferable if you specifically require Zigbee or Thread and can work around the IMU’s limitations.
Let’s break this into parts to evaluate Google Find My Device (FMD) support, battery-powered device suitability, and the impact of the new nRF54L series from Nordic.
1. Google Find My Device (FMD) Support
Google’s Find My Device (FMD) network relies on BLE for location updates via nearby devices. The requirements include:
- BLE 5.0 or higher with support for Extended Advertising and Privacy features.
- The ability to periodically transmit data while remaining energy-efficient.
nRF52840 Xiao Sense
- Fully supports BLE 5.0, including extended advertising, which is critical for FMD.
- Nordic has a robust history of enabling BLE-based location services, and their SDKs often include examples tailored for such use cases.
- The lower power consumption in sleep mode (4-5 µA) makes it ideal for transmitting periodic FMD beacons without draining the battery.
Xiao MG24 Sense
- The MG24 also supports BLE 5.3, which is more than capable of handling FMD. However:
- The lack of ecosystem maturity compared to the nRF52840 might mean more development effort if no ready-made libraries are available for FMD-specific implementations.
- Higher power consumption for BLE operations compared to the nRF52840 could make it less attractive for ultra-low-power devices.
Winner for FMD: nRF52840 Xiao Sense
- The nRF52840’s BLE performance and low power consumption make it better suited for FMD in a battery-powered setup.
2. Battery-Powered Device Suitability
Key aspects for battery-powered designs include low sleep current, efficient active current, and availability of power-saving features.
nRF52840 Xiao Sense
- Sleep Current: 4-5 µA.
- Optimized BLE operations with long battery life, even for continuous Bluetooth advertising or connection scenarios.
- Robust peripheral control, including DCDC regulators and event-driven interrupts, to minimize power consumption.
- Proven real-world performance in battery-operated IoT devices.
Xiao MG24 Sense
- Targeted for Zigbee/Thread, which typically involves mesh networks rather than ultra-low-power single-node operation.
- Sleep current specs are higher than nRF52840, and polling (due to the lack of IMU interrupt) further increases consumption.
- While suitable for Zigbee battery-powered nodes, it may not perform as well for BLE-centric battery applications.
Winner for Battery-Powered Devices: nRF52840 Xiao Sense
- It remains unmatched for ultra-low-power BLE applications with the added flexibility of IMU interrupts.
3. Considerations for the nRF54L Series
Nordic’s nRF54L series is a significant step forward, offering:
- BLE 5.4 support with advancements like Periodic Advertising with Responses (PAwR) and LE Audio.
- Greater processing power, memory, and ultra-low-power performance.
- Targeted improvements for use cases like location tracking, IoT, and advanced BLE operations.
Advantages of the nRF54L over nRF52840
- Lower Power: Nordic claims the nRF54L series consumes even less power than the nRF52840 in both active and sleep states.
- Enhanced BLE Features: BLE 5.4 introduces advanced advertising methods and energy-efficient protocols ideal for battery-powered FMD use.
- Processing Headroom: Future-proofing for more complex applications with additional computing power and memory.
- Privacy and Security: Enhanced cryptographic capabilities for modern security standards.
How Does it Compare to the MG24?
- The nRF54L is more specialized for BLE than the MG24, which leans toward Zigbee/Thread.
- If low power and BLE functionality are paramount, the nRF54L would outclass the MG24 in almost every aspect.
Availability
- While promising, the nRF54L series is very new and may not yet have mature board designs or SDK support in platforms like Arduino. It might require significant development effort compared to the established nRF52840.
Overall Recommendation
- For Immediate Use: Stick with the nRF52840 Xiao Sense for now:
- Best balance of power efficiency, BLE performance, and ecosystem support.
- Direct compatibility with FMD and battery-powered device requirements.
- Future Consideration: Evaluate the nRF54L series as it becomes more accessible:
- It’s likely to be a superior choice once mature boards and software are available, especially for applications like FMD.
- Avoid MG24 Unless Zigbee/Thread is a Must:
- While capable, the MG24’s lack of IMU interrupt support and less competitive BLE power profile make it less ideal for your BLE-based and low-power needs.
END… Of soap box. The choice is pretty clear for me. I would entertain any constructive comments though so feel free to do so
GL PJ