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My arduino powered firework sequencer. 2018 version!

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CopperCone:
you can have a static charge occur between the igniter wire and the earth. Should not happen because of insulators but charcoal and metal powders are conductive and you have moisture. You need to ensure there is a favorable area for a spark to form away from the powder charge chamber. Only posted because it's not obvious and relates to why metal/shield design is a good idea. Or a spark occur on a broke igniter wire, they are usually thin or very fragile if you are 'smart' enough to use a light bulb. 

stj:
it's obvious most people here dont know electric matches are a virtual shortcircuit and need a MINIMUM 0f half an amp to fire - usually atleast double that to be sure it will go.

they arent like airbag triggers - they cant be fired by static.

CopperCone:

--- Quote from: stj on July 04, 2018, 04:36:34 pm ---it's obvious most people here dont know electric matches are a virtual shortcircuit and need a MINIMUM 0f half an amp to fire - usually atleast double that to be sure it will go.

they arent like airbag triggers - they cant be fired by static.

--- End quote ---

its well known that they are surrounded by a conductive powder. It's also obvious that if you beak the wire a spark gap forms. If the enclosure is wet or covered with powder, and touches the earth, a spark gap forms between the wires connected to the igniter and the chassis.

It's also obvious that you don't need much energy to ignite a microscopic particle of carbon that has had oxidizer and sulfur beat into it by a ball mill or recrystallized inside of it.
Even if you use smokeless powder or pyrodex (which has charcoal in it) its often lubricated by very fine graphite (forgoing the usual conductive charcoal black powder), though it should be more difficult to ignite so long its been polished well in a mill to break off corners that can lower ignition temperature. But transport and temperature fluctuations may cause a fracture and formation of small particles that have a drastically lower ignition behavior.

 :blah:

usagi:

--- Quote from: stj on July 04, 2018, 04:36:34 pm ---it's obvious most people here dont know electric matches are a virtual shortcircuit and need a MINIMUM 0f half an amp to fire - usually atleast double that to be sure it will go.

they arent like airbag triggers - they cant be fired by static.

--- End quote ---

yep, pyrogen igniters are very robust electric firing devices -- which explains why they are used. they are very safe and reliable. the only unintentional ignition i can recall is due to direct lightning strikes on the shooting site, no real way to prevent that!

nichrome igniters are also an option. you need a beefy system to ignite them though. the igniter wire is also very fragile and easy to break when fusing up.

my firing system has safe defaults, multiple interlocks, and idle shunts. the system uses encrypted spread spectrum with 2-way handshaking. i even have separate i2c buses for devices, none of the buses are shared.

Teledog:
Nifty stuff! :D
Friends in the entertainment business were always using pyrotechnics for stage shows.
Strange happenstance that Big Clive just did a video on the electric matches;

Looked them up, and the specs do state 500mA for a single match & 800mA for series ignition.
Doubt I'd ever get into it (with our nanny state laws), but interesting non-the-less!  :)

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