Before revision: Another design combined the battery with a capacitor to power a pocket calculator for up to one minute at a time .A modification suggested by "BotherSaidPooh" of Hackaday uses a modified "phatlight" red LED with its reverse diode disconnected via laser ablation, yielding slightly more power due to closer bandgap match
After revision: Another design combined the battery with a capacitor to power a pocket calculator for up to one minute at a time