Flickering lamp

Mar 09, 2012 12 Replies

I am working on a "toy" which has a 6 volt lamp. I want it to flicker a bit. Is there a simple way to do this?



Rich


In simple, do you want to buy a device to do this,

or,

Do you want a simple DIY project ?

Lots. Assuming you have a microprocessor in there somewhere, run the lamp from a current-limited power FET such as a VNP20N07 using PWM, and make the duty cycle whatever you like. Lamps flicker quite strongly with voltage changes of only 10% or so, so you don't need to turn the thing all the way off.

The current limiting action is important so that the FET doesn't blow up when the bulb filament breaks and shorts the terminals briefly. (Of course using a big beefy FET is the other approach.)

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net

hich has a 6 volt lamp. =A0I want it to flicker

I was thinking he could adapt a flickering LED tea light, which go for about a dollar these days.

which has a 6 volt lamp. I want it to flicker

Yes, but they have an LED and a 3 Volt battery.

SO a little modification would be necessary.

Here is how I made little Xmas tree lights.

See Flickering Lamps on a.b.s.e.

On a sunny day (Fri, 9 Mar 2012 09:48:35 -0800 (PST)) it happened spamtrap1888 wrote in :

Even cheaper is using a defective bulb :-)

You can prototype it with a little 6-pin or 8-pin micro + BJT or whatever driver, but go to an ASIC for production, assuming it's a high-volume toy.

which has a 6 volt lamp. I want it to flicker

Those use a CMOS COB, very small (ASIC) simple circuit chip with

99.99% wafer yield and cost in the $0.001 area (the epoxy blobbed on top costs more).

For a hobbyist, that is a QND and inexpensive way to go.

This looks pretty simple

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r

Wow! So many ideas. This is great. My toy will probably be one off. This approach looks like it is within my skill set. I am off to the shack tomorrow. Thanks to you all. This is my first post to this site and I am a happy poster.

Rich

r

This is probably a graet approach, but it is probably beyond my present ability. Rich

If you want to wiggle it a bit in analog, you can use a 555 driving a voltage divider on the gate of the VNP20N07. Nice thing is that it's a very hard part to blow up.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net

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