sequences and input

kaz

hi,

we are trying to make our stamp listen for an input sequence. we've tried embeded if statements and they don't seem to want to work.

anyone know how to make this work?

Andy Lindsay (Parallax)

Could you be a little more specific? What sequence are you looking for? Please also post the code you using to discern the sequence.

kaz

we are looking to use switches attached to the feet of the user to control a robot's motion.

so, we are trying to figure out how to make the stamp listen for when 1 switch is pressed then another.

something like this:

if switch1 = 1 then switch2 = 1
do this

that part is easy, but we also need it to do the reverse

so

if switch1 = 1 then switch2 = 1
do this
if switch2 = 1 then switch1 = 1
do this2

so we need the stamp to distinguish the order of the switches being triggered

Andy Lindsay (Parallax)

Your design is commonly referred to as a state machine.· Here is a an example of a simple PBASIC state machine; hope·it helps.· Good luck with your robot design.

state VAR Nib
stateOld VAR Nib

DO

· state.bit0 = switch1
· state.bit1 = switch2

· IF state <> stateOld THEN

··· SELECT state
····· CASE %00
·······action = Do_Something
···· CASE %01
······ action = Do_Another_Thing
···· CASE %10
······ action = Do_That_Other_Thing
···· CASE %11
······ action = Fall_Over
···· ENDSELECT

· ENDIF

· GOSUB Perform_Action

· stateOld = state

LOOP

Andy Lindsay (Parallax)

Oops, sorry.· The previous post did not deal with the previous state of the switches.··Here is a modified example·that makes decisions based on·both the·previous and current states of the switches.·

state VAR Nib
stateOld VAR Nib

DO

· state.bit0 = switch1
· state.bit1 = switch2

· IF state <> stateOld THEN

· · IF state = %01 AND stateOld = %10 THEN
· ··· action = Do_Something
·· ·ELSEIF state = %01 AND stateOld = %11 THEN
·· ·· action = Do_Another_Thing
··· ELSEIF state = %10 AND stateOld = %00 THEN
····· action = Do_That_Other_Thing
···· .
·· · .
··· ·.
·· ·ENDIF

· ENDIF

· GOSUB Perform_Action

· stateOld = state

LOOP

Post Edited (Andy Lindsay (Parallax)) : 2/14/2006 6:49:14 PM GMT