This very simple brake light circuit is activated with the brake lights, just connecting it by diodes D1 and D2. The diodes may be of type 1N4002, and the common red LEDs. R1 to R12 resistors are 220 Ω x 1 W can be used high-brightness LEDs. The circuit was found in an American 1983 publication called Electronics Handbook Volume XIII, which contains a lot of very simple circuits.