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Help with creating remote igniter

TmatFX

Feb 3, 2014
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Hello folks,

Working on a remote igniter. I'm using the following parts.

32 gauge nichrome wire (as the igniter element)
12 volt DC 6 amps on/off remote relay kit
9 volt battery
copper wire 22g

I have constructed the project for the purpose of igniting flash paper. The nichrome wire gets red hot and is able to light the paper, however the remote kit does not shut off. The remote kit has been tested and works with different load (small light bulb). The kit sticks in the on position when the nichrome wire is being used as the load/igniter element.

Can anyone advise me on this and/or offer a solution? I need to be able to shut it off with the remote but for some reason the relay sticks. This is one of my first projects. Any direction would be greatly appreciated.

Thanks,
Ted
 
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Arouse1973

Adam
Dec 18, 2013
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Do you have a spec sheet for the remote unit. What power source are you using? What length of wire are you using?
Adam
 

TmatFX

Feb 3, 2014
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Hey Adam,

I taking spec. from the box.
12v DC to 12vDC switch by remote.
Max.= 6A output/72 watt
Cable lengths 16 inches. I may need to add another 24 inches to that.
using a 9 volt Alkaline battery.

Thanks for your time

Ted
 

GonzoEngineer

Dec 2, 2011
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I don't think anyone is going to give you advise on this, unless you can explain your purpose and prove to them that it is not nefarious!
 

TmatFX

Feb 3, 2014
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To all concerned members,

I understand your concerns.. about this project. I will explain... I own 1098 Consulting& Special effect we provide Special effects and weapons for Film and Stage. www.facebook.com/1098Consulting

I currently working on a film project where One sheet of flash pager needs to get ignited. I was hoping to do it remotely so the actor would not get distracted by hitting a switch. I will explain further if necessary and answer any questions.

Thanks for your reply.

Regards,
Ted
 

davenn

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Sep 5, 2009
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you already have another thread on this
starting 2 threads on the same subject only confuses everyone

Dave
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Does it shut off if you tap the relay?

It sounds like your relay may be having its contacts welded shut by the current drawn by the piece of wire.

A heavier duty relay, or finer wire (that doesn't require so much current to heat it to the desired temperature) would be better.

I'd also investigate using a solid state relay so you don't have to worry about clicks on the soundtrack.

edit: Thanks Dave. TMatFX, don't tell me I've wasted my time. It's really annoying.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Threads merged.
 

TmatFX

Feb 3, 2014
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Thx!

Steve,

I will try your recommendations and let you know how it turned out.

Thanks,

Ted
 

Arouse1973

Adam
Dec 18, 2013
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32 gauge will have something like 10R/ft. So even with 1ft, the wire should draw approx. 1.2Amps.

Adam
 

TmatFX

Feb 3, 2014
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Adam,

Thanks for your reply! I appreciate your expertise in this area however, Please forgive my ignorance... can you explain your reply. Iam totally green with this subject.


Thanks,

Ted
 
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Arouse1973

Adam
Dec 18, 2013
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The wire will have a resistance which will limit the current to the Voltage divided by the resistance. 12V/10R=1.2A. Your relay can switch 6A so this will be fine. The more wire you use the less current you will draw from the supply. I'll see if I can calculate the temperature rise.
Adam
 

Arouse1973

Adam
Dec 18, 2013
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For Nichrome wire the temperature rise is roughly as follows.

For 32AWG the temp rise is approx. 32 degrees centigrade per watt. So for 12 inches of 32 AWG at 12V will be 12V/10.55R = 1.13A and power is I^2*R = 13.56W. Temp rise is thus 32*13.56 = 433 degrees centigrade. If you want to use a longer wire the you will have to increase the voltage by 12V for each extra foot of cable to maintain the same temperature wire, subsequently if you reduce the cable by 1/2 of its length you double the temperature. If you coil up the wire then reduce the current by approx 1/2.

Thanks
Adam
 

TmatFX

Feb 3, 2014
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Your a genius

Adam... I increased the voltage to 12v.. it works great! Thank you!
However... the 12 volts 1.5 amps was achieved by using a AC adapter. How can I get 12 volts and the 1.2 a needed with a batter back. Appreciate your feedback.

Thanks,

Ted
 

Arouse1973

Adam
Dec 18, 2013
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Increase the amount of wire slightly. It's that simple. More wire equals more resistance which equals less current. But you will get less heat.
Adam
 

TmatFX

Feb 3, 2014
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Heat

Adam... I need the coil to get red hot.. within 3-5 seconds. any ideas?

thanks,
Ted
 

Arouse1973

Adam
Dec 18, 2013
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Now your using a coil? I think it would be better if you could supply a simple drawing with the dimensions you want the wire to cover and the type of battery you are using, Voltage and mAh. But initial thoughts is your going to need more power. Red hot is probably in the range of 800 degrees C. Can you get hold of a 12 Volts car battery then we have something big to play with.
Adam
 

jpanhalt

Nov 12, 2013
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How big an area are you trying to ignite? If a small spot will suffice, I see no need for a large battery and current demanding coil. A single, 1200 mAH NiCd will light a model glow plug for quite awhile.

John
 

TmatFX

Feb 3, 2014
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battery

Adam,

Nichrome wire coiled up to save space.. sorry I should made that clear. Is there anyway to get 12 volts. and 1.2 amps in a small battey pack.. similar to this device. This one is 9 volts. please take a look. I tried to buy it but its sold out every where.

http://www.penguinmagic.com/p/S13831

This is a demo of the device


Thanks for all you help.. I really appreciate it.. Sorry for all the questions.I need to get this completed by next week or I'm screwed.

Thanks,

Ted.
 

TmatFX

Feb 3, 2014
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Jpanholt,

Im trying to ignite a sheet of flash paper remotely.. its for a movie shoot. Im trying to copy this device which is sold out everywhere in the USA. Here is a link to the device.

Thanks for your time.

Ted
 
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