[sci.electronics] alpha light flasher

system@sys6626.bison.mb.ca (Victor Spicer ) (04/06/91)

I designed an electronic "alpha-inducer" LED flashing circuit which
works very well. It uses a chip designed for flashing LED's, the
8 pin LM 3909. Connections are as follows:

        Pin             Connection
        1               NC
        2               + of 100uf electrolytic
        3               NC
        4               wiper tap of 100k pot, gnd
        5               + 3 volts
        6               + LED connection
        7               NC
        8               - of 100uf electrolytic
                        other connection on 100k pot

Power is provided by 2 alkaline D cells, which can keep the unit
running for several months of continous use. The D cells are necessary
to provide sufficient current to the LED's.

Frequency range is about 1 Hz to 40 Hz. LED's are looked in parallel
and epoxied into holes drilled in a pair of sun glasses. The highest
intensity LED's that can be found are best.

The unit is best used in a darkened room, with your eyes closed.

Experiments with this unit have revealed some interesting results. At
higher frequencies, your eyelids start twitching in sync with the
flashes. It can be used in conjunction with a GSR device (the one Radio
Shack sells works very nicely). It also does a good job of freaking
out guests who wonder what the basement full of electronic widgets is
about....                       :-)



....
        victor spicer           sysop system 6626
        63 point west drive
        winnipeg manitoba canada

INTERNET: vspicer@ccu.umanitoba.ca              OR
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