Electronics Blocks for Basic Sensor-Based System System Design and Problems (II)

Overview Design Objective What is MiWi MiWi and Zigbee MiWi wireless solution Limitations

Design Objective WSN for E-blocks Can be easily setup by user Low cost solution

What is MiWi The MiWi protocol is free, small footprint protocol developed for customers who do not need ZigBee protocol, but want to use IEEE standard for low-cost p2p, star and mesh network.

MiWi and ZigBee MiWiZigBee Max 1k nodesMax 65k nodes 4 hops maxInfinite hops Dynamic network topology Small footprintLarge footprint Provide under free license (with the condition must use microchip microcontroller and MRF24J40) Need ZigBee protocol certificate.

MiWi Wireless Solution

MiWi Wireless Solution (Mesh Network Model) Mesh Network

MiWi Wireless Solution IEEE ™ FUNCTIONAL DEVICE TYPES Full Function Device (FFD): ▫Can be PAN coordinator, coordinator or end device. ▫Support majority of services. Reduced Function Device (RFD): ▫Can communicate with its parent only. Talk to other via coordinator. ▫End device only. ▫Require less amount of RAM and ROM.

MiWi Wireless Solution MiWi™ PROTOCOL DEVICE TYPES PAN Coordinator: ▫One per network. Form the network, allocated network addresses, holding binding table. ▫Must be FFD. Coordinator ▫Extends the physical range of the network. Allow more nodes to join the network. ▫Can be PAN Coordinator if needed. ▫Must be FFD. End Device ▫Performs monitoring and/or control functions. ▫Can be FFD/RFD.

Limitations Maximum 8 coordinators with 127 nodes per coordinator. ▫Will not cause a serious problem. Maximum 4 hops per message ▫Modify MiWi protocol stack ▫Build own protocol on top of MiWi protocol stack

Next… Building Eblock sensor. Continue study on MiWi protocol stack. ▫Some known problems and existing solutions. Construct a simple MiWi hardware using microchip PIC Micro and MRF24J40 transceiver.