Wireless firing system

[schroedinger]

Hi

 

as i was thinking about building my own firing system, would like it to be wireless.

 

I found this remote switch is 12 channel

• Channel: 12
  
• 315MHz
  
• Power supply: DC 12V
  
• Relay: 10A/120VAC
  20A/14VDC
  
• Relay bandwith: AC 110 - 240V oder DC 0 - 28V
  

 

I`m not sure if this would be suited to be used for the system.

 

 

 

Did i understand it right, that i would build a circuit witch contains a LED and resistor limiting current flow to 10 mAmp,So a power is going trough the ematch but, less then what you need to set it of?

[eb11]

I was told not to use a relay for a firing system from a licenced pyro only use ic chips for the firing circuit. this is a picture of the circuit I have designed with a lot of help from an electronics chat room. it is an 80 cue circuit that shots a shell at a predetermind time. http://screencast.com/t/ngIvEaj61yTh Edited August 14, 2013 by eb11

[Bobosan]

Might want to read the threads below as they will give you an idea of current requirements and limits for e-matching.

 

http://www.pyrouniverse.com/forum/showthread.php/6189-DIY-wireless-slats-many-cues

 

http://www.pyrouniverse.com/forum/showthread.php/18109-Firing-System-Panel-Designs-amp-Diagrams

[eb11]

who you referring to bobosan. I cant view it my virus software keeps kicking me out Edited August 14, 2013 by eb11

[Bobosan]

Anyone who wishes to view. I have heard that some antivirus programs see that forum as dangerous. The home page URL is http://www.pyrouniverse.com/

 

There are a few members here that also use the site. I've never had a problem with it.

[nater]

That is correct, you do not want a firing system that uses relays. I have seen this happen first hand twice and heard about it numerous other times. If a salute or hard breaking shell bursts near the system, the vibrations can trip the rely causing everything still live to fire. That could raise the potential for a bad accident, especially if a flowerpot destroyed a rack and then more shells fired that could be pointed any direction. It is wide to reduce the risk and use a solid state system.

[SekndAmendment]

Yeah, no relays. I've done some nifty stuff with a small RF receiver, stack of cheap LCR components, 9V battery, couple logic gates, and some high-gain operational amplifiers all duct taped onto a breadboard...it was cheap but it wasn't very robust. I mean, you could technically consider what we built a relay, but there was no switching mechanism. No power enters the circuit without an input from the RF receiver. We used them to remotely ignite 8' diameter rubber balloons filled with hydrogen after touchdowns at the local high school football games. The city wouldn't let them use a cannon with powder charges because it would be too scary and could possibly offend people that are opposed to guns or artillery. They wouldn't let us shoot rockets or use any type of BP or any other combustible pyro compounds. We asked about popping big balloons and they OK'd that. I asked if I could put something in the balloons that would increase the sound and only make a brief flame with some water as the only byproduct. They loved it because I said there was no black powder smell or smoke cloud....Retards. The balloons were much louder than the small ROTC cannon!!!

 

They were great for our needs. On the output we had a small filament on a rack and pinion set with a small DC motor. The filament would receive current and glow red hot as the DC motor turned the pinion and pushed the rack (with the filament attached to the rack) towards the balloon. It would puncture and ignite. The mechanism would fall on the grass behind the scoreboard and we could pick it up and use it again. We had to make 4-5 of them so there'd be one for each touchdown. Each circuit had to be tuned to amplify the output from the RF antenna at a different frequency so we could use the same transmitter to light them all by just changing the frequency of the transmission. They were pretty fun and I could see it being adapted for rockets...but only 1 at a time. It wouldn't work for lighting a whole show...and hard-wired is my favorite for that anyway. I get nervous with too many receivers and too many transmission bands too close together. It's a superstition or paranoia of mine. I like the hard-wired stuff.

[mike_au]

I've said this before, and it doesn't seem to be a popular opinion (especially on pyrouniverse) but I don't trust any wireless firing system without some sort of smarts at each end. Most of the radios people are using for these builds are AM (and therefore more prone to interference) and have no checksuming, error detection or error correction capabilities.

 

If all you are doing is lighting off a couple of cakes in the backyard then it probably isn't too big a deal, but if you are lighting something with enough kick that it could switch a relay then IMHO you should be using reliable communications.

 

I've had plenty of people tell me that I am being over cautious or that there is no risk, but so far all of their arguments have been along the lines of "I've never had anything bad happen" rather than actual evidence that the radio link is safe so not exactly compelling evidence in my opinion.

[schroedinger]

Ok, i checked with the PU sites, and found that the offer i found was the guy who is selling the receiver´s on PU. ^^ Also found that the circuit is quite easy to make up, so i think i will start soon to build this (as time allows it).

 

For the test circuit´s i think i will go with some 3mm 10 mAmp 12V LED`s, should be enought, or would be 5mm with 20 mAmp still be ok? (as i still have heaps of those)