Hackerspace of Things

Goal

Create a wireless mesh network at Hack Manhattan so that every electrical item can be pinged from anywhere in the world via IPv6, and controlled and/or monitored if appropriate.

July 2015 update

Everything sucks. First version will be no mesh, just raw 802.15.4 in a single PAN. Components:

• SAM D21
• AT86RF212B radio
• Johanson ceramic chip antenna
• BME280 temperature/humidity/pressure sensor
• A few MOSFET, H-bridge or opto-isolator outputs
• 12V input with buck converter
  • Possibly also compatible with lithium polymer batteries

June 2014 update

We have a 60x37mm PCB on its way with Atmel's AT86RF212B chip for 915 MHz 802.15.4. It will have a SAM D21 microcontroller with 128/256 KB flash and 16/32 KB SRAM. That should be enough for both the USB stack and 6LoWPAN, but we will see.

Technology

6LoWPAN

IPv6 over Low power Wireless Personal Area Networks is a protocol that allows IPv6 to run over 802.15.4 wireless networks. 802.15.4 is a physical layer that supports both mesh and star topologies and is used by ZigBee, 6LoWPAN and a few other protocols. There are currently variants of 802.15.4 for 2.4 GHz and 915 MHz, with other bands under development. We will probably use 2.4 GHz for interference robustness.

802.15.4 packets can only be 127 bytes long with a header of up to 25 bytes. 6LoWPAN has stateless IPv6 header compression so everything will fit.

Motes

The devices or nodes that form a mesh network are often called motes. We will build our own mote. It may have the following features:

• Several GPIO pins
• Several ADC channels for sensors
• SPI and I2C for sensors
• On board thermistor
• One or more MOSFET for power control
• Battery charger
• USB port for battery charging and for plugged in power
• LEDs for indication
• Piezo buzzer

802.15.4 SOCs

ATmega128RFA1

AVR core, essentially the same radio as AT86RF231. Probably easiest to get started with. Early units will be based on the STK600-ATmega128RFA1 evaluation kit. Contiki supported.

EM351

Silicon Labs. Questionable tool support. Cortex-M3.

MC13224V

ARM7TDMI. Modules already exist.

Energy Micro parts

Extremely low power consumption, including 6 mA, 0 dBm on 2.4 GHz. Parts will be ready in late 2013.