PIC powered by capacitor for 0,5 second

[flotulopex]

This circuit will control a "stop-light" made of LEDs located in the center of the rear-window of a car.

There are two wires powering the "stop-light". Only 0V is constant and V+ comes when you go on the brakes.

My first idea was to install a third permanent V+ wire but the engineers from RENAULT made things not a simple way and it is almost impossible to do so .

Function of the circuit: when I go on the brakes, all LEDs light-up.

If I go on the brakes a second time:
- more than half a second later (> 0,5s), all LEDs will light-up again;
- less than half a second later (< 0,5s - or, if I go a second time on the brakes within half a second), I will activate a function that makes my LEDs scroll.

[Ioannis]

OK. Now is Clear. Well, the 1 Farad is very large capacitor at 5.5Volt. I think is the cheaper and easiest solution.

Only as a precaution, use a small resistor of 100 ohms to charge it, not directly at +5V.

Ioannis

[Acetronics2]

Hi, Roger

Why not, when removing power, enter a BASIC .5 seconds SLEEP command, and then verify if power is still here ???

Think to modify the WDT prescaler ... cause PbP sets it to 128 ( the 2.3 s granularity ! )
See OPTION Reg setting (in PBPIC.xx LIB ... ???)

The capacitor size could be reduced ...

Alain

[Luciano]

This circuit will control a "stop-light" made of LEDs located in the center of the rear-window of a car.

Function of the circuit: when I go on the brakes, all LEDs light-up.

If I go on the brakes a second time:
- more than half a second later (> 0,5s), all LEDs will light-up again;
- less than half a second later (< 0,5s - or, if I go a second time on the brakes within half a second), I will activate a function that makes my LEDs scroll.

Hi Roger,

Not allowed in Switzerland, in case of a car accident you will have a problem.

The police will stop your car immediately and you will have to fix the car and then
go with the car to the "Service des automobile" of the canton where the car is immatriculated.

Best regards,

Luciano

[flotulopex]

I know that...

But what would be the taste of Life if there is no risk?

BTW, with this circuit, I will "harm" myself only.

Thanks anyway for warning.

[flotulopex]

Thank you Luciano!

It works perfectly with a 1000µF according to your schema and BODEN disabled.

Try to show the final result in a few days...