Whether it is required to simulate an open fire in a nativity scene, a forest fire in a model railway landscape, a log fire in a doll’s house or simply for an artificial candle, neither steady light nor the commercially-available regularly flickering lights are very realistic. The circuit described here imitates much better the irregular flickering of a fire.For maximum flexibility, and to reduce the component count to a minimum, a microcontroller from the Atmel ATtiny range has been selected to generate the flickering pattern. Two miniature light bulbs, each driven by a transistor, are controlled using a PWM signal to produce eight different light levels. Potentiometer P1 in the RC network adjusts the speed of the clock to the microcontroller, and hence the speed of the flickering.