Player Detector for ComupterCraft (CraftOS 1.8)

--Programm to be used with CraftOS 1.8+ and a "Player Detector" from the mod "Advanced Peripherals"

local detector  = peripheral.find("playerDetector") --finds and gives the Player Detector an "address"
local range = 3 --Change this value to the number of blocks you wish to detect the player (centre is the Player Detector)

function detectorCheck() --This checks if the Player Detector is coneected to the sytstem.

if detector == nil then
 print("Player detector not attached.")
  else
  term.write("Player detector block connected. ")
  print(detector)
  end
end

--main code
detectorCheck()

if detector == nil then
 sleep(1)
 print("Terminating program...")
 sleep(1)
 error()
  else
  print("Redstone output set to 'back'")
end

while true do

local inRange = detector.isPlayersInRange(range)
local prevInRange = false
local day = os.day()
local time = os.time()


    if inRange == true then
        term.write("Day "..day.." @ ")
        term.write(time..": ")
        print("Player detected.")

        while inRange == true do
            redstone.setAnalogOutput("back",15)
            sleep(0.5)
            inRange = detector.isPlayersInRange(range)
        end
    end

    if inRange == false then
        term.write("Day "..day.." @ ")
        term.write(time..": ")
        print("Player no longer detected.")

        while inRange == false do
            redstone.setAnalogOutput("back",0)
            sleep(0.5)
            inRange = detector.isPlayersInRange(range)
        end
    end
end