startup.lua

forward = false

function pulse(colour)
    redstone.setBundledOutput("back", colour)
    os.sleep(.1)
    redstone.setBundledOutput("back", 0)
end

function moveForward()
    pulse(colours.blue)
    print("Moving forwards")
end

function moveBackward()
    pulse(colours.white)
    print("Moving backwards")
end

while true do
    local wait
    if colors.test(redstone.getBundledInput("back"), colors.pink) == true then
        forward = false
    end

    if colors.test(redstone.getBundledInput("back"), colors.red) == true then
        wait = true
        forward = true
    end

    if forward == true then
        if wait then
            for i=1, 6 do
                print("Waiting... " .. i)
                os.sleep(1)
            end
        end
        wait = false

        moveForward()
    else
        moveBackward()
    end

    os.sleep(1)
end