Discussion in 'The Projects Forum' started by Roy, Feb 27, 2009.

  1. Roy

    Thread Starter New Member

    Feb 27, 2009
    :confused: Can anyone help me please?

    Basically, I want to flash an L.E.D. on and off.

    I have a solar powered, bright -white led device which charges 2 Nmh cells connected in series.
    When the light level falls, the led turns on until it drops the supply voltage ( 2.4V ) below a set amount, to protect the battery from being discharged too much.

    I simply want to modulate the constant light output, with brief off periods, of say 1 every few seconds. Ideally the off periods need to appear to be random.

    The additional circuitry must be powered by the supply voltage to the led and should be as simple as possible.

    I thought of 2 or 3 gates all switching the same led at around 3, 5 and 9 seconds so that the flicker would appear random, but will gates run on such a low supply voltage.

    If you can advise me, the extra drain should be negligable.

    Any ideas please???