-- Program that sends a redstone pulse at noon and midnight

-- the side of the computer to output the pulse
local SIDE = "right"

function pulse ()
    rs.setOutput(true, SIDE)
    os.sleep(0.05) -- maybe sleep for a tick?
    rs.setOutput(false, SIDE)
end

while true do
    local timedelta = os.time("ingame") % 12
    if timedelta < 0.2 then -- too strict?
        pulse()
        os.sleep(0.2) -- don't pulse more than once
    else
        local sleep_amt = 60 * (12 - timedelta) / 2 -- cut the time in half?
        os.sleep(sleep_amt)
    end
end