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

MAG. REED SWITCH

DC MOTOR

TOUCH SENSOR

IR SENSOR

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

Intro to Cricket Logo

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 inputto 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 statementto 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/turtl

elogo/