ComparatorWatcher v0

rednet.open("right")

local args = {...}

if args[3] == nil then
  print("usage: " .. shell.getRunningProgram() .. " <comaparator side> <low> <high>")
  error()
end

local side = args[1]
local low  = tonumber(args[2])
local high = tonumber(args[3])


local on = redstone.getAnalogInput(side) <= low

function checkSwitch()
  if on then
    if redstone.getAnalogInput(side) >= high then
      on = false
      return true
    end
  else
    if redstone.getAnalogInput(side) <= low then
      on = true
      return true
    end
  end
  return false
end

function stateStr(state)
  if state then
    return "on"
  else
    return "off"
  end
end

print("startup " .. stateStr(on))
rednet.broadcast(stateStr(on))

while true do
  local e, p1, p2 = os.pullEvent()
  print(e)
  if e == "rednet_message" then
    if p2 == "stateplease" then
      rednet.send(p1, stateStr(on))
      print(os.clock() .. " sent " .. stateStr(on) .. " to " .. p1)
    end
  end

  if e == "redstone" then
    print(os.clock() .. " " .. redstone.getAnalogInput(side))
    if checkSwitch() then
      rednet.broadcast(stateStr(on))
      print(os.clock() .. " switch " .. stateStr(on))
    end
  end
end