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External Interfaces and Software Tools for Electronic Blocks

Shawn NematbakhshUniversity of California, Riverside

Thesis Defense

Dr. Frank Vahid, Chairman

Dr. Harry Hsieh

Dr. Walid Najjar

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eBlocks What are eBlocks?

Single-function blocks that snap together to build useful simple systems.

Each block contains its own microcontroller to process data.

Three types of blocks: Input, output, computation. Current protocol completely binary: YES/NO.

eBlock Project Goals Allow construction of simple monitor/control systems in

a short period of time. Allow inexperienced users to build simple systems that

would otherwise be impossible.

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Overview

eBlock External Interfacing Internet Telephone PDA

eBlock Software Tools eBlock Simulator Programmable eBlock

Sample Application Parking Lot Monitor

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eBlock External Interfacing eBlock systems designed to be entirely self-

contained. Sensors, buttons, lights, buzzers, etc all implemented

as stand-alone eBlocks Would be useful to interface with external non-

eBlock systems. Devices and technologies already exist to perform

tasks that would be inefficient to implement as stand-alone eBlocks.

Three interfaces created: Internet, Telephone, PDA.

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Network eBlock Intended for long-range monitoring of eBlock

systems. Takes input from eBlock system, output to

ethernet interface. On startup gets IP of listening host + gateway

networking information from user. Constantly streams UDP packets with eBlock

status to listening host.

Network

eBlock

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Network eBlock Listening socket program on host defines behavior.

“Ships” with application outputting date/time of input change to web page.

Users can define own behavior with C API. Many possible applications

Record and display every packet received. Send email when “YES” packet is received. Output packet data to IRC chat channel. Any network application required – completely customizable.

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Phone Dialer eBlock Takes eBlock input, on startup is configured with a

target telephone number. Connects to telephone line. When ‘YES’ packet is received dialer opens line and

calls target number, waits 30 seconds, and hangs up. Intended for remote emergency alerts such as intrusion

or disaster detection.

DialereBlock

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Phone Relay eBlock “Reverse” of phone dialer block – takes a telephone

input and outputs to an eBlock system. User dialing in enters code to stream ‘YES’ or ‘NO’

packets to system. Packets sent continuously until next call.

Intended for remote control of eBlock systems Sample application: toggling lights in house while on

vacation to deter theft.

Phone RelayeBlock

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Palm Logger Palm PDA application used to record history of input

changes. Data saved on Palm system in text file for later analysis. eBlock input fed through converter device to translate

TTL to RS232 for Palm use. Solves problem of automatic monitoring of eBlock

status.

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eBlock Software Tools

eBlock External Interfacing Internet Telephone PDA

eBlock Software Tools eBlock Simulator Programmable eBlock

Sample Application Parking Lot Monitor

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eBlock Simulator eBlock simulator allows drag-and-drop layout and

testing of eBlock systems. Simulation-based testing of eBlock systems without

physical construction, saving construction time. Input, computation, and output blocks supported.

Input blocks simulated with user input toggling state. Output blocks simulated with visual alerts. Computation blocks display current state.

Stepwise simulation or real-time.

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eBlock Simulator As design is layed out, table keeps track of

blocks and connections. Cycles disallowed. Simulation algorithm:

Evaluate() produces block output based on inputs + block type. UpdateDisplay() changes display to reflect output.

Running time: O(V+E) (V=blocks,E=wires) because of topological sort

Simulate(table T[n]): Ordered=TopologicalSort(T). for i = 1 to n do

Evaluate(Ordered[i]) UpdateDisplay(Ordered[i]))

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eBlock Simulator eBlock Simulator widely used.

Basis for current version in use by over 500 people. Allows worldwide eBlock use without distributing sets of

physical blocks. Simulator useful for testing and feedback.

Allows eBlock designers to judge user understanding of blocks.

Able to test and change block customization without physical construction. Ex: 2-input logic user interface.

Lack of cycles a limitation – certain systems cannot be simulated.

Software simulator generally well-liked by users. What if physical systems could be built using the simulator

interface?

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Programmable eBlock Idea: Use simulator to layout eBlock system. Replace

multiple computation blocks with a single custom block synthesized to perform the same exact function for implementation.

ProgrammableeBlock

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Programmable eBlock Tool Design laid out using simulator drag-and-drop interface.

Different input blocks replaced with “INPUT” point. Output blocks replaced with “OUTPUT” point. Represent input and output points into programmable block.

Once design completed, “SYNTHESIS” button is clicked. Ordered table created from user’s design. C struct representation copied into code file along with

static code to step through table. File is compliable using PICC to program onto a

microcontroller without any code needing to be written by user.

Usable by advanced users or engineers without programming experience.

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Programmable eBlock Tool

const struct block blocks[NUMBLOCKS]={{-1,-1,INPUT,0,0,0,0},{0,-1,SPLITTER,0,0,0,0},{1,-1,TOGGLE,0,0,0,0},{1,-1,INVERTER,0,0,0,0},{3,2,OR,0,0,0,0},{4,-1,OUTPUT,0,0,0,0}};

GetOrdered(table T[n]) Call Simulate(T) Keep Ordered array and output to C code

Step (table Ordered[m]) for i=1 to m do eval[i] = Evaluate(Ordered[i]) output = eval[m]

Algorithm:

GetOrdered runs on PC, produces ordered representation in C.

Step runs on microcontroller once each time a packet is received or timeout occurs. Both O(V+E).

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Programmable eBlock After C code generation, PIC microcontroller can be

programmed. Zero programming knowledge required by user – simply

compile and download to chip. Programmable block implemented as enclosure with ZIF

socket. Allows easy chip placement after programming.

Problem: One UART per microcontroller. Separate microcontroller needed for each set of inputs and

outputs included. Extra microcontrollers serve only to receive input and send

output. Communicate with single master microcontroller to perform all

computation.

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Virtual Blocks Blocks in programmable eBlock tool do not

necessarily have to exist at physical level. Blocks implemented in C code for programmable block. No need for stand-alone eBlock implementing the same function.

Size of virtual eBlock library does not have to be limited.

Selecting a virtual block from library as simple as selecting from menu and dragging.

Fine-grained functional blocks can be created without worry of bloat.

Certain blocks requiring user customization are easier to set by computer. Ex: dial-switch timer.

Programmable blocks can be a mix of actual physical blocks and “virtual blocks” which exist only in software.

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Virtual Blocks

Two additional blocks created for programmable eBlock tool. Sequencer block used for pattern matching of previous

input. Eight previous inputs represented with {‘1’, ‘0’, ‘*’}. Ex: “*****101” outputs ‘YES’ only if previous input was ‘YES’,

previous to that ‘NO’, previous to that ‘YES’. Replaces gate-level pattern matching.

N-Timer block used to monitor time with continuous ‘YES’ packets received.

Value N from 1-59,999 specified by user If only “YES” packets have been received for N continuous seconds then “YES” is outputted for one timeout period (2 secs).

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Virtual Block Applications Sequencer

Can be used for passcode systems. Also useful for error correction – don’t sound alarm

unless motion sensor detects several consecutive YES inputs. First input may be false alarm.

N-Timer Useful for systems that perform long-range timing. Difficult for users to easily specify large periods of

time on-block: Dial and DIP switches don’t work well for customizing large values.

Best solution is to specify using computer – simply type desired value in.

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Sample Application

eBlock External Interfacing Internet Telephone PDA

eBlock Software Tools eBlock Simulator Programmable eBlock

Sample Application Parking Lot Monitor

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Parking Lot Monitor

Meter-free time-limited spaces usually monitored manually.

Chalk tire marks used to determine time elapsed. Labor-intensive: Monitor must constantly walk

around lots. Automate parking lot monitoring using

electronics. Keep track of time elapsed in parking space. Wirelessly alert car driver several minutes before

expiration. Wirelessly alert lot monitor at expiration.

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Parking Lot Monitor from Traditional eBlocks

Infrared receiver / transmitter placed across parking space. Logic blocks set to trigger when pulse goes low (time

exceeded) and infrared beam is broken (car still in space). Two extended pulse generators performing timing of deadline

time and deadline time minus 5 minutes so driver gets chance to move car before time expires.

IR RxBlock

IR BeamTx

SplitterBlock

Pulse Gen.Block

(deadline)

Pulse Gen.Block

(deadline--)

2-IN LogicBlock (01)

2-IN LogicBlock (01)

WirelessTx Block

WirelessTx Block

WirelessRx Block

(to attendant)

WirelessRx Block(to user)

Buzzer Buzzer

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Parking Lot Monitor with Dialer Dialer used to send alerts to user and monitor.

Advantage: Replaces six wireless receiver, transmitter, and buzzer blocks with two dialer blocks.

Advantage: Not range-limited like wireless eBlocks. Advantage: Doesn’t require external buzzer to carry

around. Disadvantage: Requires user to have mobile phone. Disadvantage: Requires phone line near parking space.

IR RxBlock

IR BeamTx

SplitterBlock

Pulse Gen.Block

(deadline)

Pulse Gen.Block

(deadline--)

2-IN LogicBlock (01)

2-IN LogicBlock (01)

PhoneDialer

PhoneDialer

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Parking Lot Monitor with Programmable eBlock

Replaces five blocks used for timing with a single programmable eBlock.

Programmable block created with splitter and two N-Timers.

Advantage: Five to one block reduction. Advantage: Easier to design and understand for user.

IR RxBlock

IR BeamTx

PhoneDialer

PhoneDialer

Split

N-Time

N-Time

blocks[NUMBLOCKS]={{-1,-1,INPUT,0,0,0,0},{0,-1,SPLITTER,0,0,0,0},{1,-1,NCOUNTER,14,16,0,0},{1,-1,NCOUNTER,12,128,0,0},{2,-1,OUTPUT,0,0,0,0},{3,-1,OUTPUT,0,0,0,0}};

Programmable eBlock

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Parking Lot Monitor from Components

Parking lot monitoring system also implemented with traditional components.

With schematic from web, construction required 8.5 hrs compared to 1.25 hrs for traditional eBlock construction.

Microcontroller programming required for component version, but not necessary for eBlock construction. Component version not buildable for non-programmers.

Component version allows more flexibility, but eBlock design meets all requirements in this case.

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Conclusion and Future Work Conclusion

eBlocks have been expanded to use external interfaces, allowing a wide range of powerful new systems to be created.

eBlock software tools were created that are being built on and improved today. These tools allow large scale use and experiment on eBlocks, and are the basis for eBlock synthesis.

Future Directions Expand the library of virtual blocks to include many more

functions useful for systems. Improve the synthesis tool to perform advanced optimizations

such as design minimization and partitioning across multiple blocks.