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Without using a microcontroller how would you flash an LED 10 times in 1 second and then stay lit thereafter? Answered

 Assumes only 1 physical input.  I am trying to mimic a brake light flasher where the driver presses on the brakes and the brake light quickly flashes for 1 second or so and then just goes to solid.  Thanks,


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Best Answer 8 years ago

This circuit can drive 300ma of LEDS 10 pulses and stay on...   .   .   A


8 years ago

555 timer plus 4017 decade counter..

VERY common circuit.

it has 10 outputs
set them to
(in order, you'll only use 9 of the 10 outputs)
0 on
1 off
2 on
3 off
4 on
5 off
6 on
7 off
8 on

where on indicates the output goes through a diode to your led driver (probably a transistor). Off indicates unconnected

the trick is to have output 8 ALSO connected through a diode to the inhibit pin so that the 555 will stop pulsing, and stop updating the 4017

The last trick is to ensure that when power is cut, no big capacitors keep the circuit energized - you want it to reset back to zero whenever power is cut.