Computercraft sensor

local sensor = peripheral.wrap("openperipheral_sensor_0")
local bsensor = peripheral.wrap("openperipheral_sensor_0")
local monitor = peripheral.wrap("monitor_4")

monitor.clear()
monitor.setCursorPos(1,1)

local pIn =
{
    ["jonassvensson4"] = false
}

-- Get users outside the shop
function getUserOut()
  playersb = bsensor.getPlayers()
  if playersb[1] == nil then
       -- No one is outside
  else
    usernameOut = playersb[1].name
    for name, status in pairs(pIn) do
      if pIn[usernameOut] == true then
        monitor.setTextColor(colors.red)
        monitor.setCursorPos(1,1)
        monitor.write("Please come again!")
        monitor.setTextColor(colors.white)
        monitor.setCursorPos(1,2)
        monitor.write("  " .. usernameOut)
        sleep(1)
        monitor.clear()
        pIn[usernameOut] = false
      end
    end
  end
end

-- Get user who enters the shop
function getUser()
  players = sensor.getPlayers()
  -- Checks if there's a player inside the shop
  if players[1] == nil then
    username = "null"
  else
  -- Player found
    username = players[1].name
    for name, status in pairs(pIn) do
      if pIn[username] == true then
        -- Player has already been in the shop
        playersb = bsensor.getPlayers()
        if playersb[1] == nil then
            -- No one is outside
        else
            usernameOut = playersb[1].name
            if pIn[usernameOut] == true then
                pIn[usernameOut] = false
                break
            end
        end
      elseif pIn[username] == false then
        pIn[username] = true

        -- Welcome message:
        monitor.setTextColor(colors.green)
        monitor.setCursorPos(1,1)
        monitor.write("     Welcome!")
        monitor.setCursorPos(1,2)
        monitor.setTextColor(colors.white)
        monitor.write("  " .. username)
        sleep(2)
        monitor.clear()
      end
    end
  end
end

while true do
  monitor.setCursorPos(1,1)
  getUser()
  sleep(0.75)
end