Switch-Operated Elevator

Two of my 9th grade students created this elevator. It raises up at the press of a switch, then waits for another press before descending. The motors also gear down for increased torque.

Ways to Program a Loop

If you need a switch to work repeatedly when you run its program, you need to loop it. Here are some ways depending on exactly how you want them to work:

;this strategy repeats indefinitely
to main

loop
[commands to loop]

end

;this strategy makes the program run itself indefinitely
to main

commands to loop
main

end

;this strategy repeats the commands many times
to main

repeat 100
[commands to loop]

end

Many Ways to Program Switches

;simplest way, one switch
to go

waituntil [switcha = 1]
motor commands
waituntil [switcha = 1]
more motor commands

end

;another way, one switch
to go

if switcha = 1
[motor commands]
if switcha = 0
[more motor commands]

end

;another way, one switch
to go

ifelse switcha = 1
[motor commands]
[more motor commands]

end

;two switches!
to go

if switcha = 1
[motor commands]
if switchb = 1
[more motor commands]

end