The peltier element comes from a mini fridge i found in the dumpster. It was used to cool a swedish type of tobacco called snus.

The cooling module was in the bottom and on one side was the black cooling element that you see in tho top of the finished build. On the other side (the cool side) was a big circular block of aluminum. This whole module was used upside down where the heat from the candle now acted on the original cool side.

The peltier is connected to a joule thief and then a LED.

Since it takes a long time for a candle to heat up the big block of aluminum there is around 15 mins of delay from lighting the candle until the LED goes on. Also when you put out the candle it stays lit for another 10 mins or so due to the heat differential still in the large mass of metal.