Applications and Experiments with eBlocks – Electronic Blocks for Basic Sensor-Based Systems Susan Cotterell, Kelly Downey ŧ, Frank Vahid ¥ * Department.

Applications and Experiments with eBlocks – Electronic Blocks for Basic Sensor-Based Systems

Susan Cotterell*, Kelly Downeyŧ, Frank Vahid*¥

* Department of Computer Science and Engineeringŧ Department of Electrical Engineering

University of California, Riverside{susanc, kstephen, vahid}@cs.ucr.edu;

http://www.cs.ucr.edu/eblocks¥ Also with the Center for Embedded Computer Systems at UC Irvine

This work is being supported by the National Science Foundation and a Department of Education GAANN Fellowship

Susan Cotterell and Frank Vahid

UC Riverside 2 of 15

A Typical Problem

Garage door ... left open at night - Oops!



Solution: A Simple “Embedded System”

Blink LED in bedroom if garage open at night

Homeowner sees LED before bed

Components needed LED Contact switch Light sensor Logic (no light AND switch

not closed) Wireless transmitter Wireless receiver

LED

light sensor

contact switch

AND

receive

transmit



Possible solutions

Alarm company -- too expensive Off-the-shelf

Low volume product: hard-to-find, costly Inflexible: What if two garage doors;

notification in 2 places; audible alert? Vendor can’t include everything

Build it yourself Should be feasible for semi-skilled

person Hard! -- Find components (where?), read

datasheets (tough), program microcontrollers (much skill), build circuit boards (more skill)

Low power issues Battery drains in 2 days Need packets and sleep - more skills

Experiment 50 skilled students (CS, EE) given weeks 60% did not complete

40%’s solutions were not power efficient No way regular person could build it

http://www.smarthome.com



What’s Needed

The wood and nails of the sensor world

So novices can build simple things and semi-skilled people even more



Our Solution – Off-the-Shelf Easy-to-Use Electronic Building Blocks -- eBlocks

eBlocks – Electronic Building Blocks Enable people with no programming or

electronics expertise to build sensor-based systems

Basic block with predefined functions Standard plugs and communication Connected like Legos, interchangeable

Battery powered (wall/other power optional)

First version: Boolean (“yes/no”) eBlocks (future: Integer blocks) Sensors like motion, light, sound, button,

contact, etc., send Boolean (“yes” or “no”) Outputs like LED, beeper, electric relay,

PC, etc. Compute blocks perform logic & state

functions

Motion Sensor

Light Sensor

Button

Beeper

LED

About 15 basic blocks

yes/no

yes/no

yes/no

yes/no

yes/no

2-Input Logic

yes/no

yes/no

yes/no Toggle

yes/no yes/no

Tripper

in

rst

“Once yes, stays yes” (until reset)

Other logic/state blocks

“Opposite”

“Yes prolonger”

“Pulse generator”Button yes

Button no

yellow means ERROR

green means YESred means NO



Connect eBlocks to Build Application

Basic blocks enable variety Garage Open At Night Detector Flexible: 2 garages, >1 alert... Different applications w/ blocks Enables mass production

Low cost: ~$4 (Harvard Bus.Sc.) Available: next to wood/nails?

2003-2004: ~100 prototypes, 15 types

Size: deck of cards PIC processor and electronics 2+ years on 9-volt battery

Protocol/architecture: ISSS/CODES’03 Illusion of continuous

communication, but packets & sleep Constraints & timeouts (data, alive)

ensure connect/disconnect response Hands-on -- intuitive, few

abstractions Enables step-by-step design: DEMO

LEDwireless RX

Outside

Light Sensor

Magnetic Contact Switch

2-Input Logic

wireless TX

Inside houseAt garage door

2-Input Logic Toggle

Button

LED

Button

LED

KitchenService Line

Splitter



1000s of Applications, Not Just Garages

Countless applications Residential

Wireless doorbell, mail alert, gate open, motion on property, package on porch, customized motion lights, carpool alert

Office/Commercial Cafeteria food alert, front desk

notifier, conference rooms in use, copy machine in use, visitor at front gate, reserved parking spot detector

Health Sleepwalker detection, hard-of-

hearing sound alert, water leak alert...

Environmental Temperature logging, animal

tracking, ... And others… Current projects

Endangered species photography project with county

Developing an elder wellness home monitoring project with major company



eBlocks and “Traditional” Sensor Networks

Each eBlock has specific function User does not write programs

Only minor configuration may be required Connecting blocks creates end-application Programming is an option

Wired connections Makes connectivity explicit (intuitive),

less power, lengthens distances (2 miles)

Wireless point-to-point link is an option eBlocks NOT a replacement for

traditional sensor network nodes; instead:

1. Some systems eBlocks only, or front (or back)-end to PC or appliance

2. Front (or back)-end to sensor-network nodes

3. Sensor-network nodes inside eBlocks

Motion Sensor

Light Sensor

Beeper

2-Input LogicWireless

Transmitter

Wireless Receiver

eBlock-only application

Front/back-end to traditional sensor network nodes

eBlock Sensor

eBlock Sensor

eBlock Sensor

eBlock Logic Block

eBlock State Block

Node

Node

Node

Configured to AB’

A

B

eBlock Sensor

eBlock Sensor

eBlock Logic Block

Node

Node

Node

eBlocks implemented with traditional sensor network nodes

oror



Experiments

Button

Kitchen

Splitter

Can people of varying skill levels build basic sensor-based systems using eBlocks?

Sensors-with-logic Sensors-with-logic-and-state

Sensors-with-state

Cafeteria Food Alert

Toggle2-Input Logic

LED

Service Line

Button

Daytime Doorbell

2-Input Logic

Light Sensor

ButtonBeeper

LED

Tripper

in

rst

Front Desk Notifier

BeeperToggle

Package Delivery Alert

Button Beeper

Motion Sensor

Button

Garage Open at Night

LEDLight Sensor

Magnetic Contact Switch

2-Input Logic



Experiments

Prototypes and graphical simulator Users of varying skill

Beginners: non-science/non-engin. majors in required computer applications course

Intermediate: first year programming course

Advanced: upper-division embedded systems course

Just 1-minute introduction, no grade Thus, students not particularly

motivated But we didn’t want to influence the

results Motivated people performed much

better No assistance (from us or others)

Short time: 8-10 minutes Tests whether immediately

understandable Success improves with time



Results

Sensor-with-logic Sensor-with-state

Sensor-with-logic-and-state

Success Rate

Num. Student

s

Success Rate

Num. Student

s

Success Rate

Num. Student

s

Beginner 35 % 86 100 % 2 0 % 2

Intermediate

47 % 113 56 % 101 0 % 21

Advanced 85 % 82 80 % 65 28% 16

Overall 54 % 281 66 % 168 12 % 39Good % given building

systems with multiple blocks, configuring logic, in just a few

minutes

Basic state blocks seem intuitive.

Students need more time to build more complex systems

Success rate increases with experience level. Also, plenty

of close solutions.

All experiments: students had less than 10 minutes to complete

yes no

The output should be

When the input is out

A B

A BA BA BA B

Combine

Combine

AND OR

yes no

When A is yes no

B is

then the output is yes



Previous Work –Programmable Products

Customizable Solutions User selects sensors and

actuators, possibly connect to central device

Nodes or central device programmed by the user Programmed via Visual

Basic, C/C++, Graphical languages, etc.

Domains Education/Toys

MIT Crickets, Lego Mindstorms

Industrial Phidgets, Teleo

Sensor networks Motes, Smart Dust

Requires user programming

Phidgetshttp://www.phidgetsusa.com

accelerometerlight sensor

joystick

Teleohttp://www.makingthings.com

LegoMindstormshttp://www.mindstorms.lego.com

Mica Moteshttp://www.xbow.com

ir sensor

potentiometer

temperature sensor



Previous Work –Board & Block Products

Electronic components Users connect components to build

systems Functionality defined within individual

block Some too simplistic for building sensor

based systems – intended for younger audiences

Some intended for other domains Hobbyists Electronics education

Logiduleshttp://diwww.epfl.ch/lami/teach/ logidules.html

Logiblocs http://www.logiblocs.com

Electronic Blockshttp://www.itee.uq.edu.au/~peta/

_ElectronicBlocks.htmRobobrix

http://www.robobrix.com

Kharma, N. and L. Caro. MagicBlocks: A Game Kit for Exploring Digitial Logic. American Society for Engineering Education Annual Conference, 2002.



Summary and Future Work

Summary Developed a set of electronic building blocks – eBlocks Discussed applications and relation to traditional sensor-

network nodes Initial studies show that users can effectively build basic

systems Present/Future Work

Improved success rate through intuitive logic/state blocks (CHI’05 HCII’05 submitted)

Extend eBlocks to integers (presently Boolean) Integer sensors, arithmetic compute blocks Wider-range of systems

PC-based tools for more experienced users Programmable eBlock Automated design synthesis from simulator-based design

(DATE’05 submitted)

Power sharing through wires CAD tools to build eBlocks themselves (DATE’05 submitted)

Applications and Experiments with eBlocks – Electronic Blocks for Basic Sensor-Based Systems Susan Cotterell, Kelly Downey ŧ, Frank Vahid ¥ * Department.

Documents

basic blocks yesno

eblocks electronic blocks

frank vahid uc riverside4

frank vahid uc riverside2

frank vahid uc riverside6

frank vahid uc riverside5

frank vahid uc riverside3

frank vahid uc riverside7

Applications and Experiments with eBlocks – Electronic Blocks for Basic Sensor-Based Systems Susan Cotterell*, Kelly Downey ŧ, Frank Vahid *¥ * Department.

Applications and Experiments with eBlocks – Electronic Blocks for Basic Sensor-Based Systems Susan Cotterell, Kelly Downey ŧ, Frank Vahid ¥ * Department.