FLASHING BULB CIRCUIT WANTED.....

030902040607020204010102 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit

Hi all, I'm looking for a circuit, either a kit, or built that will flash low wattage 12 volt lamps AT RANDOM. I need to flash about 25 bayonet bulbs, a bunch at a time but completely random. Like if I just used old style flashing bulbs with the bi-matalic strip inside. Also it would need the capability to change speed. Does anything like this exist without spending a lot of money??

THANKS!!

Reply to
Steve
Loading thread data ...

ash

The usual source of "random" signals is a pseudo-random binary sequency generator.

formatting link

The sequence of "0" and "1" states it produces isn't actually random, but a long enough shift register won't repeat itself for quite a while and is random enough for your kind of application,

Horowitz and Hill's "Mastering the Art of Electronics" has a useful section on the subject in chapter 9.32.

These days a professiona engineer would realise the shift register and the exclusive-OR gate in a programmable logic array or a single-chip microprocessor, but you can still buy cheap CMOS shift registers and OR-gates, and use the shift register's parallel outputs to drive the gates of 25 cheap N-channel MOSFET transistors to control your lamps.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

ash

A little off the beaten track, but it might work. (?)

Get a box and attach little strips of metal inside so that the edges line up close to each other. Each pair of strips will form one switch. The gap between the metal strips should be small, maybe 0.1 inches apart. Connect it all up.

Then fill the box with ball bearings and shake. Adjust amount and size of ball bearings until you get the effect you want.

MacGuyver up some way to shake the box and you're done!! :)

Reply to
mpm

--
There are at least three problems with that approach, the first being
that it won\'t at all simulate incandescent lamps with mechanical
 Click to see the full signature
Reply to
John Fields

"John Fields" schreef in bericht news: snipped-for-privacy@4ax.com...

The 555 solution looks promessing. But you may need to take measures to prevent the individual circuits from "seeing" each other. I once experienced that similar circuits synchronized after some time. Never had the change to look after the cause but I guess they influenced each other via the power lines. For the same reason the gates-solution may not randomize.

petrus bitbyter

Reply to
petrus bitbyter

flash

ust

Steve doesn't seem to want to simulate lamps with mechanical flashers

- he's merely asking for something similar.

This doesn't seem to cut into the sales of LED-based flashing lights

Sonce the 555 doesn't have a lot of common mode rejection, this is unlikely to be true. I suppose that anybody silly enough to propose wiring up 25 555-based drivers has to be silly enough to be unaware that buying twenty-five identical resistora and capacitors is likely to get you parts from the same manufacturing batch, which will be much closer in value that the specified tolerance, so there might not not be a lot of unit to unit variation between the array of 555-base flashers to prevent the switching spikes from one part from triggering all the other parts that are close to switching, and eventually forcing most of the flashers to cycle in concert.

The kind of elaboration that often goes wrong ...

You really do want Steve to do a lot more soldering that he has to, don't you.

Are there an endless supply of wet-back wiremen in Texas who will work for peanuts?

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

PLA's? uP's??? That's like using a cruise missile to kill a mouse. Google "relaxation oscillator". P.U.T.'s are still available from ON Semi (and maybe others) for about a dime ea. Freq can be varied by varying the charging resistor. Add an NPN to the output to drive the load.

5 or 6 parts per flasher output should about do it. Art
Reply to
Artemus

What is your solution Bill?

Ed

Reply to
ehsjr

None. He's all critique and no solution, just like Ms Prissy ;-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
 Click to see the full signature
Reply to
Jim Thompson

Interesting problem. Kudos to mpm (alias Rube Goldberg) for the ball bearing solution. LOL

Don't they still make LED's with blinking circuit built in? Do those have good common node rejection? Do they end up synching up with each other?

Could the LED's with blinking circuit inside be used to drive FET driver transisters?

Reply to
Greegor

I think it's a given that, unless you have phenomenal VDD filtering, relaxation oscillators tend to at least "semi-sync".

...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
 Click to see the full signature
Reply to
Jim Thompson

G > Interesting problem. G > Kudos to mpm (alias Rube Goldberg) for the ball bearing solution. =A0LOL

G > Don't they still make LED's with blinking circuit built in? G > Do those have good common node rejection? G > Do they end up synching up with each other?

JT > I think it's a given that, unless you have phenomenal VDD filtering, JT > relaxation oscillators tend to at least "semi-sync".

Would the blinker LED's at least make the amount of filtering required more readily attainable?

G > Could the LED's with blinking circuit inside be used G > to drive FET driver transisters?

Reply to
Greegor

Jim Thompson seems to forget that he can't read my posts, so he hasn't actually read what I posted on the 19th. It's not a fully worked out solution - I haven't specified a clock generator to clock the pseudo- random binary sequence generator, nor specified the the CMOS shift registers that you might use to build it or the "n" and "m" numbers for a particular pseudo-random binary sequence generator - but I could do it in a couple of minutes. It isn't exactly rocket science, even if John Fields finds it intimidating.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

The one I posted on the 19th, which John Fields doesn't seem to like - a pseudo-randon binary sequence generator,

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

ash

emi

The OP want 25 lamps. Twenty-five times five or six parts is 125 or

150 components.

A pseudo-random binary sequence generator is a little more economical

- fewer parts and fewer solder joints.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

--
Well, then, I guess I should have said:

"There are at least three problems with that approach, the first being
 Click to see the full signature
Reply to
John Fields

--
Then do it instead of just saying you can, and post your circuit.
Reply to
John Fields

--
It\'s not that I don\'t like PRSGs, it\'s just that for this application,
your implementation, as presented, will be clunky.
 Click to see the full signature
Reply to
John Fields

--
Depends on what happens to Vdd/Vcc on transitions, I think.

Using 7555\'s with tiny switching transients and different supplies for
 Click to see the full signature
Reply to
John Fields

A 555 at each location allows local "stiff" filtering of the "Control Voltage" pin, which should help a lot to prevent syncing. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
 Click to see the full signature
Reply to
Jim Thompson

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.