Elevator.lua

os.loadAPI("Touchpoint")

local monitor = peripheral.wrap("left")
monitor.setTextScale(0.5)
monitor.clear()
monitor.setCursorPos(1,1)

local t = Touchpoint.new("left")
t:add("Call elevator", nil, 1, 1, 15, 6, colors.red, colors.lime)
t:add("-", nil, 1, 8, 15, 10, colors.black, colors.black)

t:draw()

while true do
    local event, p1 = t:handleEvents(os.pullEvent())
    if event == "button_click" and rs.getAnalogInput("bottom") == 15 then
        t:flash(p1)
        t:rename("-", "Going up")

        sleep(4)

        rs.setOutput("back", true)
        os.pullEvent("redstone")
        rs.setOutput("back", false)

        break
    end
end

shell.run("Elevator")