The document describes an IoT gateway solution based on the mbed microcontroller board. The gateway connects wireless sensor nodes using various communication protocols to cloud services. It has a modular, open source software design that allows new sensor nodes and cloud outputs to be added without code changes. The gateway hardware includes the mbed module, wireless modules, Ethernet, microSD card, and comes preassembled in an enclosure. It can currently transmit sensor data to Pachube and MQTT and future work involves expanding its capabilities.

1. mbed based
IoT Gateway
Andrew Lindsay
@andrewdlindsay
IoT London Meetup,
28th March 2012
Project kindly Sponsored by SK Pang Electronics Ltd.

2. The Problem?
 Lots of wireless sensor nodes within your property
 May use multiple gateways or PCs for each solution
 Different wireless communication protocols
 Different end destinations
 Too technical for average person?
 May need to write code

3. A Solution
The mbed based IoT Gateway
Connecting your IoT nodes to cloud based services

4. A Solution
 Single low power wireless gateway
 Operates with 868MHz or 433Mhz nodes
 Xbee, XRF or Wifi module in wireless option socket
 Ethernet or Wifi internet connection
 Realtime clock, updated via NTP
 μSD socket for storing configuration
 Web based management
 Software is Open Source

5. What is mbed?
 Microprocessor development board based on
NXP LPC1768
 Uses ARM Cortex-M3 core
 96MHz clock, 512K Flash, 32K RAM
 I/O includes Ethernet, SPI, I2C
 Digital, Analog, PWM
 Real time clock
 Local filesystem
 Online compiler
 Libraries and code samples
 Off-line tools available

6. mbed Vs Arduino
mbed Arduino
 NXP LCP1768/ARM  Atmel ATmega328P
Cortex M3 core
 96MHz  16MHz
 512K Flash  32K Flash
 32K RAM  2K RAM
 Ethernet  Shield
 Online compiler  Simple IDE

7. Gateway Hardware
Baseboard for mbed module
Provides power and I/O connectors
Ethernet RJ45
μSD card socket
RFM12B Wireless module
RFM22B Wireless module option
Wireless module socket for
Xbee/XRF/WiFly

8. Gateway Hardware
Baseboard for mbed module
Provides power and I/O connectors
Ethernet RJ45
μSD card socket
RFM12B Wireless module
RFM22B Wireless module option
Wireless module socket for
Xbee/XRF/WiFly

9. SK Pang Package
 IoT Gateway package consists of
 mbed and IoT Gateway baseboard
 Black extruded aluminium case with wall
mounting brackets
 Laser cut end panels
 External antenna
 9V PSU
 Ethernet Cable

10. Sensor Nodes
 Jeenodes
 OpenEnergyMonitor
 Custom sensor nodes
 Measure
Temperature, Humidity
Soil temperature
Electricity usage
Air Pressure
Dust particles

11. Software Features
 File based configuration in version 1
 Web based configuration in version 2
 Modular OO design
 No code changes to add new nodes
 Configuration files stored on μSD card
 Can learns about new nodes
 Input from wireless nodes
 Output to Pachube/MQTT
 Open Source
 Available from mbed.org

12. Inputs
RFM12B, either 433MHz or 868MHz
Compatible with
Jeenodes from Jeelabs
emonTX from OpenEnergyMonitor
Custom data formats, V1/V2 including battery status
Extendable
Alternative inputs/outputs
RFM22
Xbee
XRF from Ciseco plc

13. Outputs
Current Outputs
Pachube API V2
MQTT including Pachube MQTT beta
Future Outputs
Xbee
XRF
RFM12B
WiFi

14. Data Routing
 Direct input sensor reading to an output
 Nodes file defines how to decode data
 Routing file defines where readings go
Pachube datastream
MQTT message
 Multiple readings can be batched

15. Web Management
 Simple Management interface via browser
 Configure network parameters, DHCP or Fixed
 Configure output modules
 List known nodes
 Configure nodes
 List known sensors
 Configure sensor outputs
 Still a work in progress

16. Where to next?
 Expand range of input payload types
 Ability to transmit wireless messages
Equipment: fans, pumps, vent openers.
Displays: emonGLCD
 Other cloud based data services
 Community involvement
 Custom hardware without mbed

17. Resources
Some resources used in this project
 www.skpang.co.uk
 mbed.org
 jeelabs.org
 pachube.com
 mqtt.org

18. Thank You
Thanks to SK Pang for providing the IoT Gateway
http://bit.ly/IoTGateway
Questions?