Pick the right wireless sensor/controller for your connected MCU-based design
802.15.4 Alternatives
A variety of protocols can be chosen, but some are very complex and others are evolving. The most common options were discussed above with 6loWPAN the leading candidate in the long term.
For the most part, these radios come without protocols on a single chip rather than in a module because they are unregulated in the ISM band and do not require rigorous certification. Some chips come with on board modules and although simpler from a hardware point of view offer limitations if the protocol stack does not have all the required features because flexibility is much lower.
How to get started on your design
With the broad range of choices outlined so far it is no small wonder that designs are confused. Here are some simple rules to get started:
1. Know the data rate, power and range. This will immediately limit the choices.
2. Choose a business model for wireless service that fits the application.
3. Have a specific set of requirements once the technology choices are narrowed and try for industry standards if possible. This will determine the type of protocols that will be needed and keep you in the mainstream of implementation which will reduce costs and increase flexibility.
4. Target multiple module vendors to create choices, reduce costs and reduce risks for moderate volume applications.
5. For high volume applications, prototype with modules and move to a custom implementation.
6. On the MCU or MPU, select an operating system with support for the type of wireless you require. For example, if using a WiFi high performance module on an MCU, make sure that the OS has support for this type of module.
Kim Rowe is the founder of RoweBots Research Inc., the manufacturer of the Unison OS. which offers a complete set of wireless support for a broad set of applications, chips and modules - WiFi, Bluetooth and Bluetooth LE, 6loWPAN, SimpliciTI, MiWi, Zigbee, GPS, GPRS/GSM and proprietary radios – all of which are integrated with the Unison TCP/UDP/IPv4/IPv6 protocol stacks, BSD sockets interfaces and other serial line disciplines as required. Bluetooth profiles, drivers for specific chips, custom protocol support and other more custom offerings are available on demand.
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