Lua Helmet addEvent [1.4.2]

[lexus21]

Hi, I'm trying to create a helmet with an event. When equipped, it should execute the script every second, but it doesn't - it executes once when equipped.

function onEquip(player, item, slot)
     addEvent(function()
             print("working")
         end, 1000, cid)
end

I also tried another option: (draft)
in this code, equipping this helmet triggered an event and removing the helmet stopped the event, but the change (swapping helmets) duplicated the events and e.g. I swapped helmets 3 times and the event triggered 3 times

function onEquip(player, slot, item)
        startScript(player)
end

function startScript(player)
        eve = addEvent(startScript, 1000, player:getId())
        print("working")
end

function onDeEquip(player, item, slot)
        if eve then
            stopEvent(eve)
            eve = nil
        end

end

What is a good way to start an event after equipping the helmet and end the event after taking the helmet off? (so that swap does not duplicate events)