[SML] 12V flicker fire effect?

[e-mail frank.wood95]

By far the simplest way is to build several astable multivibrators,
one per two bulbs. These are one of the most elemrntary circuits, each
needing two transistors, two bulbs, two resistors, and two capacitors.
The transistors should be rated for the bulb current. Any elementary
electronics textbook will show you the circuit, and tell you how to
calculate the component values for given rates of flicker.

There is no need of printed circuit boards, as a 'bird's nest' wiring
arrangement will be perfectly adequate. Personally, I have made them
using the 'festoon' bulbs made for car interior lighting. There
should, though, be a fuse in the battery supply.

Make it on a baseboard, of suitable size and shape, cover with
suitably coloured gel, and matt black spray paint according to your
artistic judgement. Note that there should be some bulbs permanently
on.

To trigger it on, I suggest that you use lines 5 to 8 of the decoded
DMX signal you heve available, gated together with diodes, and a
larger power transistor. At least one of these will go positive for
any level above 50%. As an alternative, a push-on/push-off switch
operated by an actor or crew member will do.

I have made several: all worked.

On 23 January 2015 at 02:42, Glenn Hoit via Stagecraft
<stagecraft at theatrical.net> wrote:
> We have used small 12v battery with an inverter and plugged in a small "Halloween type" flame cauldron....worked very well.
>
> Glenn
>
>> On Jan 22, 2015, at 5:49 PM, "Jon Ares via Stagecraft" <stagecraft at theatrical.net> wrote:
>>
>> I just know someone's done this... and probably many times....
>>
>> I need to create a 'cordless' (battery powered) burn barrel....
>> flickery flame light action... I've done this many times using AC
>> current/dimmers and fluorescent starters, but never with 12V DC. Any
>> suggestions? Anything exist to make 12V lights flicker?
>>
>> (Short of getting a 4-channel wireless dimmer... just can't afford
>> that. I do have wireless DMX, which luckily runs off of 12V as well.)
>>
>> --
>> Jon Ares
>> www.arescreative.com
>> Follow my twits @jon_ares
>>
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-- 
Frank Wood