bicycle lights and alarm

elektor july/august 1985 A bicycle or tricycle should, as everyone knows, be fitted with front and rear lights. The noteworthy aspect of the lights circuit described here is that it also provides a visible alarm, which is primarily intended for invalid road users. When such handi- capped people are in need of assist- ance during the day, this is quickly spotted by passers-by. At night, this is, unfortunately, not so, whence the present circuit. The usual dynamo or battery is replaced by a 6 V rechargeable lead- acid battery, which ensures that the bicycle lights are operational even when the bicycle is not moving. When the rider is in need of assistance, the alarm can be switched on: in addition to the normal lights, a small display with the word "HELP" will then flash. Such a signal for help is not easily overlooked! The circuit is based on an astable multivibrator, which does not operate when alarm switch S2 is open. Pro- la 2 A lb Lai = front light La2,La3 = rear lights Lag Lag...