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

1. Applications and Experiments with eBlocks – Electronic Blocks for Basic Sensor-Based Systems Susan Cotterell*, Kelly Downeyŧ, 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. A Typical Problem Garage door ... left open at night - Oops! Susan Cotterell and Frank Vahid UC Riverside

3. LED receive transmit AND light sensor contact switch 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 Susan Cotterell and Frank Vahid UC Riverside

4. http://www.smarthome.com 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 Susan Cotterell and Frank Vahid UC Riverside

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

6. LED in Motion Sensor rst Tripper Toggle yes/no yes/no yes/no yes/no Light Sensor yes/no 2-Input Logic Beeper Button Button Button yes no red means NO yellow means ERROR green means YES 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 yes/no yes/no yes/no yes/no yes/no Other logic/state blocks “Opposite” “Yes prolonger” “Pulse generator” “Once yes, stays yes” (until reset) About 15 basic blocks Susan Cotterell and Frank Vahid UC Riverside

7. wireless TX Light Sensor LED LED Outside 2-Input Logic wireless RX Magnetic Contact Switch LED Splitter Toggle Inside house 2-Input Logic At garage door Button Button Service Line Kitchen 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 Susan Cotterell and Frank Vahid UC Riverside

8. 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 Susan Cotterell and Frank Vahid UC Riverside

9. 2-Input Logic Motion Sensor eBlock Sensor Node Light Sensor eBlock Sensor eBlock Sensor Node Beeper eBlock Sensor eBlock Sensor eBlocks and “Traditional” Sensor Networks Configured to AB’ Wireless Receiver • 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: • Some systems eBlocks only, or front (or back)-end to PC or appliance • Front (or back)-end to sensor-network nodes • Sensor-network nodes inside eBlocks or A or Wireless Transmitter B eBlock-only application eBlock State Block Node eBlock Logic Block Front/back-end to traditional sensor network nodes Node Node eBlock Logic Block Node eBlocks implemented with traditional sensor network nodes Susan Cotterell and Frank Vahid UC Riverside

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

11. 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 Susan Cotterell and Frank Vahid UC Riverside

12. 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. A B yes no yes no When A is AND OR yes no B is A B When the input is The output should be A B then the output is yes A B Combine out A B Combine Results All experiments: students had less than 10 minutes to complete Susan Cotterell and Frank Vahid UC Riverside

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

14. Kharma, N. and L. Caro. MagicBlocks: A Game Kit for Exploring Digitial Logic. American Society for Engineering Education Annual Conference, 2002. 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 Logiblocs http://www.logiblocs.com Electronic Blocks http://www.itee.uq.edu.au/~peta/_ElectronicBlocks.htm Robobrix http://www.robobrix.com Logidules http://diwww.epfl.ch/lami/teach/ logidules.html Susan Cotterell and Frank Vahid UC Riverside

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) Susan Cotterell and Frank Vahid UC Riverside