[sci.electronics] Mind Machine - Need LED Flasher

whos@ddsw1.MCS.COM (Ben Feen) (04/03/91)

Help!  I want to make a "Mind machine" type device - 2 pairs of red/green
LEDs, arranged thus:

	RG           RG

I will build them into a pair of goggles, and supposedly, the correct
frequency will have psychological effects.  Now:

I want the red and green LEDS to light up like this:

	R            G   - "High" pulse
	G            R   - "Low"" pulse

Or whatever.  The point being that you see red with your left eye,  and
green with your right, and then vice-versa.  I would like to be able to use
a pot to adjust the frequency.  Now - How would I wire something like this?
A 555 timer would be perfect for this, but I don't know how to get a
symmetrical waveform.  (I am a high school 'lectronics student) He who can
develop a good circuit will win everlasting fame in the annals of... well,
I'll be really grateful, at least.

-- 
whos@ddsw1.MCS.COM | I don't know, who's at DDSW1? | whos@ddsw1.MCS.COM!
I asked YOU who's at DDSW1! Ok, there's a guy at DDSW1, right? | Right!
Who? | Exactly! | What? | No, he's at lll-winken. | Where? | No, What! |  I
don't know! | He's at gargoyle. | Who? | No, he's at DDSW1.MCS.COM!

rusty@steelmill.cs.umd.edu (Rusty Haddock) (04/03/91)

In article <1991Apr03.005649.22625@ddsw1.MCS.COM> whos@ddsw1.MCS.COM (Ben Feen) writes:
   >Help!  I want to make a "Mind machine" type device - 2 pairs of red/green
   >LEDs, arranged thus:
   >
   >	RG           RG
   >
   >a pot to adjust the frequency.  Now - How would I wire something like this?
   >A 555 timer would be perfect for this, but I don't know how to get a
   >symmetrical waveform.  (I am a high school 'lectronics student) He who can

Well... Although I thought you could get a sym wave out of a 555 maybe not --
it's been a while.  Still, there's always running the 555 about 2 times 
faster and running its output through a flip-flop.  Then, no matter how
fast you clock your 555 the output you want will be symmetric.  No?

		-Rusty-
--
Rusty Haddock / CompSci Dept		DOMAIN:	rusty@mimsy.cs.umd.edu
University of Maryland		PATH:	{uunet,rutgers}!mimsy!rusty
    If someone points a quad-vectored, hyper-thermic, cosmo blaster
       at you it's a safe bet that you're about to become toast.

amaranth@vela.acs.oakland.edu (Paul Amaranth) (04/04/91)

In article <1991Apr03.005649.22625@ddsw1.MCS.COM> whos@ddsw1.MCS.COM (Ben Feen) writes:
>Help!  I want to make a "Mind machine" type device - 2 pairs of red/green
>LEDs, arranged thus:
>
>	RG           RG
>
>I will build them into a pair of goggles, and supposedly, the correct
>frequency will have psychological effects.  

One of the electronic project magazine had a project like this within
the last couple of months.  They used a single red led for each eye with
a 555 to blink them.  The article included a discussion of the photo-optic
effect.  If you get the lights to blink at your natural alpha frequency,
your brain "locks" in on it resulting in a state of relaxation.  Apparently
you can also do this with the theta frequency, although the article was
vague on the experienced effects.

DISCLAIMER:  I have not tried this, and the article explicitly warns of
the danger of TRIGGERING AN EPILEPTIC SEIZURE IN SUSCEPTIBLE PEOPLE.

Has anyone built one of these gizmos?
-- 
Paul Amaranth  office: (313) 370 4541 (also voicemail) 
(internet)     amaranth@vela.acs.oakland.edu  | WANTED: Clever saying
(bitnet)       amaranth@oakland               | to fill this space. 
(uucp)         ...!uunet!umich!vela!amaranth  | Puns need not apply.

raoul@eplunix.UUCP (Nico Garcia) (04/04/91)

In article <1991Apr03.005649.22625@ddsw1.MCS.COM>, whos@ddsw1.MCS.COM (Ben Feen) writes:
> green with your right, and then vice-versa.  I would like to be able to use
> a pot to adjust the frequency.  Now - How would I wire something like this?
> A 555 timer would be perfect for this, but I don't know how to get a
> symmetrical waveform.  (I am a high school 'lectronics student) He who can

Connect the output of your pot-controlled 555 to the clock input of a
counter, say a '163. Take the lowest digit of the counter output as
your control signal, or higher digits for lower frequencies. (This gives
you a much lower frequency range than a normal 555 will give you, with
better control.)

Have fun....
-- 
			Nico Garcia
			Designs by Geniuses for use by Idiots
			eplunix!cirl!raoul@eddie.mit.edu

newton@ils.nwu.edu (David Newton) (04/04/91)

In article <5618@vela.acs.oakland.edu>, amaranth@vela.acs.oakland.edu
(Paul Amaranth) writes:
> In article <1991Apr03.005649.22625@ddsw1.MCS.COM> whos@ddsw1.MCS.COM
(Ben Feen) writes:
> >Help!  I want to make a "Mind machine" type device - 2 pairs of red/green
> >LEDs, arranged thus:
> DISCLAIMER:  I have not tried this, and the article explicitly warns of
> the danger of TRIGGERING AN EPILEPTIC SEIZURE IN SUSCEPTIBLE PEOPLE.
> Has anyone built one of these gizmos?

   These toys can be a lot of fun, but for a LOT of people they can be...
unsettling?  They can _easily_ trigger seizures, known as photo-epilepsy.

Dad:  "Dave?  Dave?  Are you okay?"
Dave: "*mumble mumble*"
Dad:  "Dave?  *slap slap*"
Dave: "*froth huh wha froth*?"

Yes, that was me, many many moons ago.  Ambulance, hospital, strobe
light testing, blah blah.  It was pretty cool, but don't know as I'd
want to do it again. 

Oh, the perils of being young.  (God, I was young.)

There are commercial units available at ridiculously high prices.

--
David L. Newton	    |  Work: (708) 467-1015  |      newton@ils.nwu.edu 
ILS, Room 135       |  Home: (708) 332-2321  |-------------------------------
1890 Maple St.      |-Gumby Cyberdeck Jockey-| Kicked out of alt.hackers by
Evanston, IL  60201 |__Dr. Seuss is a god.___| "Real Hackers."  Oh WOE is me.

whos@ddsw1.MCS.COM (Ben Feen) (04/16/91)

Well, I figured a circuit diagram, and after some work, the board is etched.
I will drill tomorrow, and hopefully will have a working circuit by Friday.

Also - I've sent for a catalog from a company called Zentech, a seller of
such stuff.  Will report on their quality soon.

-- 
whos@ddsw1.MCS.COM | I don't know, who's at DDSW1? | whos@ddsw1.MCS.COM!
I asked YOU who's at DDSW1! Ok, there's a guy at DDSW1, right? | Right!
Who? | Exactly! | What? | No, he's at lll-winken. | Where? | No, What! |  I
don't know! | He's at gargoyle. | Who? | No, he's at DDSW1.MCS.COM!