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Cricket (Handy Cricket). Kyeongseo Hwang (Mike) Nicholas Ver Hoeve. Agenda. About Cricket (HW) History of Logo (Built in interpreter) Intro to Cricket Logo Demo. About Cricket. LIGHT SENSOR. TOUCH SENSOR. MAG. REED SWITCH. IR SENSOR. DC MOTOR. BREAK BEAM SENSOR. History of Logo.
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Cricket (Handy Cricket) Kyeongseo Hwang (Mike) Nicholas Ver Hoeve
Agenda • About Cricket (HW) • History of Logo (Built in interpreter) • Intro to Cricket Logo • Demo
About Cricket LIGHT SENSOR TOUCH SENSOR MAG. REED SWITCH IR SENSOR DC MOTOR BREAK BEAM SENSOR
History of Logo • Logo: Developed in BBN (a Cambridge University research firm), in 1966 • By Seymour Papert, Wally Feurzeig • Modeled after LISP • Now in multiple dialects; ExperLogo, ARLogo, MIT StarLogo, NetLogo, etc. • Cricket Logo developed in MIT by Brian Silverman with Fred Martin beginning in 1995
Intro to Cricket Logo • Procedure definition with inputs and return values • Global variables and local procedure inputs • Control structures: if, repeat, and loop • 16-bit number system: addition, subtraction, multiplication, division, remainder, comparison, bit-wise operations, random function • Motor and sensor primitives • Timing functions and tone-playing functions • Data recording and playback primitives • IR Communications primitives
Motor Command • a, Motor A • b, Motor B • ab, Motor A and B • on Selected motor On • off Selected motor Off • onfor # Selected motor will turn on for #/10 secs. • thisway/ thatway Sets direction • rd Reverses the direction • setpower # set power level
Sensor Command • switcha • return 1 if switched plugged into sensor A is pressed • switchb • return 1 if switched plugged into sensor A is pressed • sensora • Report the value of sensor A 0~255 • sensorb • Report the value of sensor B 0~255
Timing and tone-playing • Timing • ab, on wait 20 off • ab, onfor 20 • wait # • timer • resett • Tone-playing • beep • note 110 30 www.handyboard.com/cricket/program
Control Structures • repeat times [body] • loop [body] • if condition [body] • ifelse condition [body-1] [body-2] • waituntil [condition] • stop(!) • output returning_value
Numbers • 16 bit number system • -32768 ~ +32767 • All arithmetic operators separated by a space • 3 + 4 • Normal expression precedence rules are not used, evaluated left to right • 3 + 5 * 7 = ? • (3 + (4 * 5)) = ?
Number Operator (cont) • + Infix addition • - Infix subtraction • * Infix multiplication • / Infix division • % Infix modulus (remainder after integer division). • < Infix LESS-THAN test. • Results in 1 if left-hand value is less than right-hand value; 0 otherwise.
Number Operator (cont) • > Infix GREATER-THAN test. Results in 1 if left-hand value is greater-than than right-hand value; 0 otherwise. • = Infix equality test. • Results in 1 if left-hand value is equal to right-hand value; 0 otherwise. • and Infix AND operation (bitwise). • or Infix OR operation (bitwise). • xor Infix exclusive-OR operation (bitwise). • not prefix NOT operation (logical inversion, not bitwise). • random Reports pseudo-random number from 0 to 32767. • Use the modulus operator to reduce the range; e.g., (random % 100) yields a number from 0 to 99.
Procedure Definition with input to flash1 repeat 10 [a, onfor 5 wait 5] end to flash2 :n repeat :n [a, onfor 5 wait 5] end global [temp] to detect settemp sensora if temp < 30 [output 1] if temp < 50 [output 2] output 3 end
Variables • Global variable • global [variable-list] e.g. global [cat dog] • Stored in RAM -> data recording and playback functions • Integer only • Global-setting primitive • setcar, setdog e.g. setcat 3 setcat cat + 1 • Global Array • array [clicks 10 clacks 15] • Array indices start at 0 • aget name index • aset name index • No buffer-overrun checking • Stored consecutively in memory • stored in the Cricket's non-volatile memory
Data Recording and Playback to take-data resetdp repeat 2500 [record sensora wait 10] end • resetdp • setdp position • erase # • record value • Recall
Recursion to fact :n if :n = 1 [output 1] output n * fact :n – 1 end -> repeat fact 3 [beep wait 1] Normal Recursion has uncertain max depth, can be as low as 5 • Supports Tail Recursion • converting the recursive call into a goto statement to beep-forever beep wait 1 beep-forever end
Multi-Tasking • supports a limited form of multi-tasking • One “background task” • repeatedly checks a condition • When true it interrupts and processes when [switcha] [beep] loop [a, onfor 5 rd] • only one background task operating at any given time. • If a when statement is executed after the background task has already been started, the subsequent when task supercedes the earlier one • To stop the background task from operating, use the primitive “whenoff”.
Samples • Files at www.cs.rit.edu/~kxh7583/PLC/ • Demo the multi-taking • IR communication between crickets • Background Operation
Reference • www.handyboard.com/cricket • http://gleasonresearch.com/http://lcs.www.media.mit.edu/people/fredm/projects/cricket/redlogo.html • http://www.papert.org/ • http://www.mathsnet.net/logo/turtlelogo/