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

2. Susan Cotterell and Frank Vahid UC Riverside2 of 15 A Typical Problem Garage door... left open at night - Oops!

3. Susan Cotterell and Frank Vahid UC Riverside3 of 15 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

4. Susan Cotterell and Frank Vahid UC Riverside4 of 15 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

5. Susan Cotterell and Frank Vahid UC Riverside5 of 15 What’s Needed  The wood and nails of the sensor world  So novices can build simple things and semi-skilled people even more

6. Susan Cotterell and Frank Vahid UC Riverside6 of 15 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 2-Input Logic yes/no Toggle 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

7. Susan Cotterell and Frank Vahid UC Riverside7 of 15 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: DEMODEMO LED wireless RX Outside Light Sensor Magnetic Contact Switch 2-Input Logic wireless TX Inside house At garage door 2-Input Logic Toggle Button LED Button LED KitchenService Line Splitter

8. Susan Cotterell and Frank Vahid UC Riverside8 of 15 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

9. Susan Cotterell and Frank Vahid UC Riverside9 of 15 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 Logic Wireless Transmitter Wireless Receiver eBlock-only application Front/back-end to traditional sensor network nodes eBlock Sensor eBlock Logic Block eBlock State Block Node Configured to AB’ A B eBlock Sensor eBlock Logic Block Node eBlocks implemented with traditional sensor network nodes or

10. Susan Cotterell and Frank Vahid UC Riverside10 of 15 Experiments Button Kitchen Splitter  Can people of varying skill levels build basic sensor-based systems using eBlocks? Sensors-with-logicSensors-with-logic-and-state Sensors-with-state Cafeteria Food Alert Toggle 2-Input Logic LED Service Line Button Daytime Doorbell 2-Input Logic Light Sensor Button Beeper LED Tripper in rst Front Desk Notifier Beeper Toggle Package Delivery Alert Button Beeper Motion Sensor Button Garage Open at Night LED Light Sensor Magnetic Contact Switch 2-Input Logic

11. Susan Cotterell and Frank Vahid UC Riverside11 of 15 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

12. Susan Cotterell and Frank Vahid UC Riverside12 of 15 Results Sensor-with-logicSensor-with-stateSensor-with-logic- and-state Success Rate Num. Students Success Rate Num. Students Success Rate Num. Students Beginner35 %86 100 %2 0 %2 Intermediate47 %11356 %1010 %21 Advanced85 %8280 %65 28%16 Overall54 %28166 %168 12 %39 Good % 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 AB AB AB AB AB Combine AND OR yes no When A is yes no B is then the output is yes

13. Susan Cotterell and Frank Vahid UC Riverside13 of 15 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 Phidgets http://www.phidgetsusa.com accelerometer light sensor joystick Teleo http://www.makingthings.com LegoMindstorms http://www.mindstorms.lego.com Mica Motes http://www.xbow.com ir sensor potentiometer temperature sensor

14. Susan Cotterell and Frank Vahid UC Riverside14 of 15 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 Logidules http://diwww.epfl.ch/lami/teach/ logidules.html Logiblocs http://www.logiblocs.com Electronic Blocks http://www.itee.uq.edu.au/~peta/_Electr onicBlocks.htm Robobrix 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.

15. Susan Cotterell and Frank Vahid UC Riverside15 of 15 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)