Choice of hardware
Choosing the right hardware is a crucial step in the development of a Zigbee gateway. There are usually two approaches to choose from, each with its own advantages and disadvantages:
Option 1: Microcontroller-based solution
For a microcontroller-based solution, chips such as the nRF52 (Nordic Semiconductor), the MG21 or the MG24 (both Silicon Labs). These microcontrollers offer built-in Zigbee capabilities and can be combined with a separate Wi-Fi module to connect to the cloud.
Advantages:
- Lower hardware costs: Microcontrollers are usually much cheaper than systems with extensive operating systems.
- Efficiency: Microcontrollers are energy-efficient, which is especially important in battery-powered scenarios.
- Flexibility: Direct access to hardware features enables optimized solutions for specific use cases.
Disadvantages:
- Higher development costs: Since microcontrollers do not have a complete operating system, many functions (e.g. protocol translation, network stack) must be developed or integrated from scratch.
- Longer development time: Development is more complex because software has to be closely aligned with the hardware.
Option 2: OpenWRT-based system
An alternative to the microcontroller solution is a system based on OpenWRT based. OpenWRT is a Linux distribution designed specifically for embedded devices. These systems use more powerful hardware, often with built-in Wi-Fi and extensive networking capabilities.
Advantages:
- Lower development costs: Thanks to the Linux ecosystem, many functions (e.g. protocol stacks, network management) can fall back on existing open source tools.
- Faster time to market: Development is less time-consuming because many building blocks are prefabricated.
- Extensibility: OpenWRT offers the possibility to easily integrate additional software or functions.
Disadvantages:
- Higher hardware costs: Systems running Linux require more powerful processors and more memory, which increases hardware costs.
- Energy consumption: Compared to microcontrollers, OpenWRT-based systems require more energy, making them less suitable for battery-powered applications.
Weighing up the options
The choice between a microcontroller or an OpenWRT-based solution depends heavily on the requirements of the project:
- If hardware costs need to be kept low (e.g. for large volumes), a microcontroller-based solution such as the MG21 or MG24 is the best choice. in combination with a separate WLAN module. However, the longer development time should be taken into account here.
- When fast development times and flexibility are in the foreground, an OpenWRT-based system offers an attractive option. This is especially useful if the gateway requires extensive network functions or frequent software updates.
A hands-on approach could be to start with an OpenWRT-based prototype to reduce development time and validate functionality. Once the design is stable, the solution can be migrated to a more cost-effective microcontroller design to reduce hardware costs.
