Computercraft Inventory Detector

c = peripheral.wrap("back")
r_side = "top"

while true do
    items = 0
    for k, item in pairs(c.getAllStacks()) do
        items = items + 1
    end
    if items == 0 then
        redstone.setOutput(r_side, false)
    else
        redstone.setOutput(r_side, true)
    end
    os.sleep(0.05)
end