SIMPLE MONITORING AND ACTION PROFILE

Stephen Dawson-HaggertyXiaofan JiangDavid Culler

Vision

Enable “Apps for the Building”

Panel 1 Panel 2

A

B

A

B

Panel 1 Panel 2

A

B

A

B

15913

172125

293337

41

371115

192327

313539

A15913

172125

293337

41

371115

192327

313539

15913

172125

293337

41

371115

192327

313539

A261014

182226

303438

42

481216

202428

323640

B261014

182226

303438

42

481216

202428

323640

261014

182226

303438

42

481216

202428

323640

B15913

172125

29333741

371115

192327

313539

A15913

172125

29333741

371115

192327

313539

15913

172125

29333741

371115

192327

313539

A261014

182226

30343842

481216

202428

323640

B261014

182226

30343842

481216

202428

323640

261014

182226

30343842

481216

202428

323640

B

SMAP

Reality

• LOTS of old, new [building, city] sensors• LOTS of legacy installed base• No lingua franca• Let’s support two things: metering and measuring– But let’s do them really well

Measuring: instantaneous values Metering: accumulated values

i.e., temperature i.e., electricity

Units

Conversion to Engineering Units

Metadata, metadata, metadata

Setting the Scene• This is topical: “smart buildings” are here today– 6lowapp– SEP: Zigbee Smart Energy Profile– GreenPlug– Google PowerMeter– CAP: Compact Application Protocol

• Lots of common requirements– Needs to be miniscule and efficient

• implementable anywhere– Represent some data simply

• Can’t do everything for everyone

Design

• Build JSON/REST/HTTP Interface• REST/HTTP– Easily understood

• JSON– Compact ASCII– Allows validation– Multiple representations possible

REST API

HTTP/TCP

…

JSON Objects

System Designor, REST in 36kB

• Build on blip, embedded IPv6 stack

• Use HTTP for control channel

• Standards in IETF, IEEE moving along nicely, but don’t get held up by them!

TinyOS/BLIP

HTTP Engine

Application Interface

802.15.4 Link

6lowpan HC

HYDRO Routing

TCP

Meter Interface: HTTP + JSON• Use HTTP as app-level control protocol• JSON is concise object transport

– Also defined a compressed application/x-binaryjson content type

• Distinguish metering from sensing• Integrate raw data with metadata

– Calibration– Engineering units

• Reporting support allows pushing of sensor data

Sensor Edge Router Proxy, Database User systems

Meter Interface/meter # meters of quantities of flow provide this service [GET] /channelID # a particular channel [GET] /reading # meter reading [GET] /format # calibration and units [GET/POST] /parameter # sampling parameter [GET/POST] /profile # history of readings [GET]/report # create and query periodic reports [GET/POST]

POST requests supply JSON objects as arguments:POST: http://meter1.cs.berkeley.edu/report { "ReportResource" : "/meter/*/reading", "ReportDeliveryLocation" :

"http://webs.cs.berkeley.edu/receivereports.php", "Period" : 60, "Minimum" : 50, "Maximum" : 100 }

Example JSON

{"UnitofMeasure" : {"type" : "string”, "options":[ {"value":"kW", "label":"kW/kWh"}, {"value":"lph", "label":"Liters per Hour"},...]}, "Multiplier" : {"type" : "integer”, "optional" : "true"}, "Divisor" : {"type" : "integer”, "optional" : "true"}, "UnitofTime" : {"type" : "string", "options": [ {"value":"millisecond"}, {"value":"second"}, {"value":"minute"},...]}, "MeterType" : {"type" : "string", "options": [ {"value":"electric"}, {"value":"gas"}, {"value":"water"},...]}}

{"UnitofMeasure" : "kW", "Multiplier" : 1, "Divisor" : 1, "UnitofTime": "second", "MeterType" : "electric" }in

stan

cesc

hem

a

Making it Affordable(for devices on a budget)

• JSON: Binary transport defined and implemented– Integers to fixed-width types– String enumerations to “c” enumerations

• HTTP: potentially compressed a la “Chopin”– Defines binary format– Optionally uses UDP transport

Compression

application/json 94 octets

application/binaryjson 22 octets

{"UnitofMeasure" : "kW", "Multiplier" : 1, "Divisor" : 1, "UnitofTime" : "second", "MeterType" : "electric" }in

stan

ce

0x21512312 0x3

UnitofMeasure

0x0

kW

0x0

Multiplier

0x11

…0x10

Length

Magic

com

pres

sed

Making it Friendly(for web devs)

IPv6 / 6LowPANWireless Mesh Network

ACme

Vibration

Temperature

ACme

ACme

HumidityInternet

Edge Router

PAR/TSR

Hardware…

HTTP

API/REST API/RESTTranslation

Making it Friendly(for web devs)

• HTTP architecture naturally supports proxies– applications don’t need to understand the

compression

Implementation

• 35k embedded TinyOS implementation– Includes IP, TCP, HTTP, SMAP

• Veris meter gateway– ~30 channel legacy Modbus device

• Cal ISO gateway– Total system demand is just another sensor!

• Android application– Uses SMAP backend

Future Work

• Data, data, and more data!– Make this ubiquitous for all Local sensors– Even port external data sources

• It’s the apps, stupid!– User portals, live data analysis, anomaly detection– Want to build on top of this substrate

• Help for legacy– Lossless XML translation– Generic SMAP/XXX gateways:

• reduces our burden for integrating new data

QUESTIONS