The document describes jNode, a wireless sensor network platform designed for distributed inertial kinematic monitoring. jNode nodes contain various sensors for measuring movement and orientation, as well as distance, light, and temperature. They use two microcontrollers running Contiki and Arduino to support standardized wireless communication and flexible experimentation. Example applications include embedded motion tracking and activity recognition.

1. jNode: A Sensor Network Platform that Supports
Distributed Inertial Kinematic Monitoring
P.M.Scholl, D.Gordon, M.Scholz, M.Berning, K.Laerhoven
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

2. Motivation
a Wireless Sensor Network Platform that:
has a large array of sensors onboard
supports reliable and quick experimentation
supports standardized wireless and wired interfaces
is small, power-efficient and extendible
Example Applications:
embedded motion tracking
ambulatory monitoring
human (group) activity recognition
Plug’n’Play solution for wireless kinematic monitoring needs
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

3. Sensors
geared towards kinematic sensing
attitude and heading / 3d orientation:
accelerometer
gyroscope
compass/magnetic heading
relative/absolute height:
barometric pressure
relative distance/reflective proximity
infrared pulsed distance
received signal strength
ambient light
ball-switch
temperature
3x IR LED for optical estimation
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

4. Processing
two micro-controllers for maximum flexibility
NXP/Jennic JN5148: Atmel ATMega32u4:
Ieee802.15.4 compliant radio includes USB subsystem
32-bit OpenRisc Architecture 8-bit Risc Architecture
96kB RAM @16MHz 2.5kB RAM @16MHz
runs Contiki OS runs LUFA (optionally Arduino)
fully re-programmable via USB fully re-programmable via USB
provides TCP/IP v6/4 communication via 6LoWPAN
provides standard-compliant USB devices
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

5. Hardware Architecture
OTAP
serial
webserver fat32
rndis/cdc ethernet
timesync µSDcard
mass storage
6lowpan tcp/ipv6
Contiki LUFA (usb)
JN5148 ATmega32u4
gyroscope
thermometer ir distance
accelerometer ball switch
barometer ambient light
compass
li-ion battery
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

6. Radio and Storage
from a data collection point of view during experimentation
Radio - Ieee802.15.4:
6LoWPAN for transmitting IPv6 via Contiki (or IPv4)
RPL/ROLL for building multihop routing tables
UDP for unreliable transport, TCP for reliable transport
time synchronization
but only reliable to the point of your control of the environment
and constrained bandwidth (up to 500Kbps)
Storage - µSD-card
fast and reliable
fat32 filesystem (most ubiquitous on usb sticks)
supported through the Contiki filesystem API (and via USB mass-storage)
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

7. Energy Consumption
component current
◦C MPL115 0.6mA
kPa 0.7mA worst-case power consumption:
lx VCNL4000 1.3mA no radio duty-cycling
cm(ir ) 1.0mA no sleeping on µCore
m/s2 LSM303 0.6mA
fastest sampling rates
gauss 0.5mA
◦ /s L3G4200D 6.2mA 36.05mA
rssi JN5148 17.5mA
CPU JN5148 5.5mA
ATmega32 10mA run-time example, 400mAh battery:
RF tx/rx JN5148 16.3mA
µSD - ~3.4mA ~11h
total RF+µSD 36.05mA still a lot to gain
total RF 32.65mA
total µSD 20mA
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

8. Example Applications
Human Activity Recognition and Embedded Motion Tracking
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven

9. Conclusion
a wireless sensor network platform
with a large array of sensors (kinematic and remote estimation)
quick and robust experimentation and standard-compliance
open-source in software and hardware
https://github.com/teco-kit/Jennisense
Thanks for your attention
14. Juni 2012 | ESS, TU Darmstadt, PCS, Karlsruhe IT | P. M. Scholl, D. Gordon, M. Scholz, M. Berning, K. Laerhoven