Apollofrost Posted March 24, 2008 Share Posted March 24, 2008 EDIT: This falls under the heading of very bad ideas and cheaper better systems can be found else where. This is more of a "oh that's interesting" project than anything useful. What you need: Wireless battery powered doorbell from homedepot 9volt battery Electrical tape NiChrome wire Altoids tin or plastic tupperware These are basic instructions from a project I did a few months ago. There are no pictures as at the time I didn't have a camera. I may revisit this in the future, but right now I have no real use for this. Ok, open the doorbell case and cut the wires going from the circuit board to the speaker. Unscrew the circuit board and clip the wires going to the battery compartment. Attach the correct leads to the correct terminals of the battery and wind with tape to ensure that they do not slip. Punch a small hole in the side of the altoids tin. Place strips of electrical tape on the back of the circuit board and place inside the altoids tin. Place the battery inside as well. Snake the two wires that went to the speaker through the hole in the side of the tin. Make an electrical igniter with the nichrome and voila! Notes: I used an altoids tin and a nine volt battery. You may want to use something different as the circuit board burned out after a day or so. I might suggest just using 3 Dcell batteries and just leaving the circuit board inside the case. READ THIS! Because it uses a common wireless doorbell any other doorbell from the same brand will trigger the device. That means that it would be very bad to try and use this in an urban environment where someone might have the same type of doorbell. Though out in a field, I doubt you would have to worry. I'm eager to see what people do with this. Link to comment Share on other sites More sharing options...
TheSidewinder Posted March 24, 2008 Share Posted March 24, 2008 Sounds OK, up to AND including the last sentence. It needs expansion though. ANY stray RF close to the required frequency could set it off. It wouldn't require someone with a nearby doorbell similar to your receiver. As far as I know none of them have encoded transmitters/receivers, though I could certainly be wrong! Correct me if so. And that *really* disqualifies its use as a pyro firing panel. I suspect if someone showed up at a WPAG shoot with one made like that, our Safety Officer would go bananas. I don't wish to discourage the "DIY" people though, so I'll add that if you could get your hands on a relativey recent Genie, etc, garage door opener whose motor has died but is otherwise fine, with fairly strong encoding to prevent false open/close, that would be safer. Still wouldn't pass Brian K's muster though. M 1 Link to comment Share on other sites More sharing options...
50AE Posted March 24, 2008 Share Posted March 24, 2008 True. I was thinking if a cell phone call could ignite it, as it does disturbance at speakers. Depends of the frequencies of course. Link to comment Share on other sites More sharing options...
FrankRizzo Posted March 25, 2008 Share Posted March 25, 2008 There's a company who makes and sells high quality wireless relay boards and transmitters on eBay very inexpensively. These units *do* have digital encoding. http://stores.ebay.com/e-MadeinCHN_Remotes...2QQftidZ2QQtZkm Link to comment Share on other sites More sharing options...
tentacles Posted March 25, 2008 Share Posted March 25, 2008 Using one of these wireless doorbells is insane. You might as well just put a long fuse on your shell, light it and carry the mortar into the field, and hope you can set it up before it goes off in your face! We have one here at work that will go off at random times, from EMI, sunspots, who knows? And that's with the transmitter a whopping 6 feet from the reciever. The encoded garage door transmitter isn't a bad idea but the range on them usually isn't too great, and they typically run on 110v. Link to comment Share on other sites More sharing options...
Apollofrost Posted March 26, 2008 Author Share Posted March 26, 2008 Eh, it was more of an whimsical project than anything. Commercial companies are bound to make a better or cheaper alternative. I just thought it might be cool to see a household item turned into something else. Link to comment Share on other sites More sharing options...
TheSidewinder Posted March 26, 2008 Share Posted March 26, 2008 Hmm... forgot about the 110v on the main receiver. However, I *KNOW* I've seen "remote-controlled" (for want of a better term) devices with strong security encoding, that ran off batteries at both ends, had about a 1000-ft range, and could easily be adapted for firing. I just can't remember where I saw them. And it may be moot: the labor involved to adapt one probably costs more than buying a "real" firing panel. And as was said, the risk is too high, at least for MY personal safety thresholds. M Link to comment Share on other sites More sharing options...
RubenE Posted March 26, 2008 Share Posted March 26, 2008 Yeah, I'd rather suggest buying a system from the guys Frank linked to. Quite a few guys on the Norwegain pyrotechnic forum are using their systems. I am personally waiting for a 12CH system myself. Stay green you know. Link to comment Share on other sites More sharing options...
TheSidewinder Posted March 27, 2008 Share Posted March 27, 2008 Do your research first. The relay-style ones are bouncy as hell and will sympathetically fire other cues. The new solid-state ones don't that have problem, though they have minor issues of their own, usually related to current draw. Link to comment Share on other sites More sharing options...
FrankRizzo Posted March 27, 2008 Share Posted March 27, 2008 Sindewinder, The relays on those new boards sold by e-MadeinCHN are rock-solid; I own two and have beat the hell out of one to test it. The old Chinese systems were bouncy like that because of a bad circuit design. Basically, the turn-on circuit was always partially energized and caused the gap between the switching electrodes to become very small and prone to shock. The newer units use a buffer chip which prevents this. Link to comment Share on other sites More sharing options...
Richtee Posted April 5, 2008 Share Posted April 5, 2008 What you need: Wireless battery powered doorbell from homedepot As mentioned, this Tx/Rx set is extremely unreliable. Let's face it... the downside of a false on a doorbell is an extraneous "bing bong". On a firing system?? I am a security and electronics professional, and could recommend units that would be MUCH safer. Digitally encoded is a great system, but I dunno about trusting it while loading a 3". I do not yet fire electrically, but plan on building a system. But I assure you it WILL NOT be wireless. Link to comment Share on other sites More sharing options...
TheSidewinder Posted April 6, 2008 Share Posted April 6, 2008 Sindewinder, The relays on those new boards sold by e-MadeinCHN are rock-solid; I own two and have beat the hell out of one to test it. The old Chinese systems were bouncy like that because of a bad circuit design. Basically, the turn-on circuit was always partially energized and caused the gap between the switching electrodes to become very small and prone to shock. The newer units use a buffer chip which prevents this. Thanks, Frank! I knew the switchover was being made, but wasn't sure how far along it was. Some of the crap units are still imported, though, aren't they? Sounds like you got two nice firing panels. Were they reasonably priced? Link to comment Share on other sites More sharing options...
h0lx Posted March 16, 2009 Share Posted March 16, 2009 How about building an extra safety arming circuit for it, like a timer? Make it so once activated, it will arm itself in like 60 seconds or so, then you will have time to retreat to a safe distance, before a stray signal could possibly ignite your device. Link to comment Share on other sites More sharing options...
andyboy Posted March 16, 2009 Share Posted March 16, 2009 How about building an extra safety arming circuit for it, like a timer? Make it so once activated, it will arm itself in like 60 seconds or so, then you will have time to retreat to a safe distance, before a stray signal could possibly ignite your device. That falls on one point but a rather large one. The use of a remote detonation system is to make you in charge of when it goes of, press the button and it goes boom. If you want it to go of at a specific time, just use the timer, no need for a remote detonating system at all in that case. Link to comment Share on other sites More sharing options...
mike_au Posted March 17, 2009 Share Posted March 17, 2009 That falls on one point but a rather large one. The use of a remote detonation system is to make you in charge of when it goes of, press the button and it goes boom. If you want it to go of at a specific time, just use the timer, no need for a remote detonating system at all in that case. I don't think that he meant "push a button and in 60 seconds it goes off" but rather "push a button and in 60 seconds the receiver will begin accepting signals". You are still in charge from the remote. I think it is a pretty good idea, although I am biased because this is exactly what my wireless system does. Theoretically, a stray signal could by chance produce a "fire" command, we reduce the chance of that happening by using encoding, encryption, etc but it is still a possibility. The benefit of the delay is that when I am up near the rack turning the receiver on, even if the air is full of valid fire signals I have 35 seconds to move away. It is just another level of security. Certainly not an alternative to encoding or encryption but I think it is a useful addition to them. Link to comment Share on other sites More sharing options...
andyboy Posted March 17, 2009 Share Posted March 17, 2009 I don't think that he meant "push a button and in 60 seconds it goes off" but rather "push a button and in 60 seconds the receiver will begin accepting signals". You are still in charge from the remote. I think it is a pretty good idea, although I am biased because this is exactly what my wireless system does. Theoretically, a stray signal could by chance produce a "fire" command, we reduce the chance of that happening by using encoding, encryption, etc but it is still a possibility. The benefit of the delay is that when I am up near the rack turning the receiver on, even if the air is full of valid fire signals I have 35 seconds to move away. It is just another level of security. Certainly not an alternative to encoding or encryption but I think it is a useful addition to them. I understood perfectly well what he meant, but the whole point is that if the receiver starts accepting stray signals as valid fire commands you are still not in charge of when it should go of. Hypothetically, you set up a charge in the woods consisting of 100 grams of flash. You set your timer and retreat to a safe distance where you can still keep an eye on it. As you are ready to press the button you see a group of children approaching the clearing where you have your charge, oops. They are going to have a picnic. So, do you still find it OK that a stray signal or atmospheric interference can set it off? Off course you can approach the charge and disarm it or tell the kids to get the F away from there but the chance for disaster is to high to risk it in my opinion. Link to comment Share on other sites More sharing options...
h0lx Posted March 17, 2009 Share Posted March 17, 2009 Well if other people are the case, then it's correct. I used to set off my stuff in large open areas, where I would see from far, far away if someone is approaching, that way I would just set it off long before someone got dangerously close to the device. Link to comment Share on other sites More sharing options...
Arthur Posted March 17, 2009 Share Posted March 17, 2009 Sorry but a roll of bell wire is cheaper and more reliable. The e-madeinCHN boards are easily bought via ebay and the coding is adequate if you change it yourself from the one factory default coding, which is easily done. Link to comment Share on other sites More sharing options...
h0lx Posted March 17, 2009 Share Posted March 17, 2009 But wire has too much resistance, if longer distances are required.. that means more bulky wire or more batteries. Link to comment Share on other sites More sharing options...
FrankRizzo Posted March 17, 2009 Share Posted March 17, 2009 Additionally, the e-madeinCHN boards can be ordered with both latching and momentary outputs on the same board. For a dual layer of security, simply wire the circuit such that both a latching relay and a momentary relay have to be switched before initiation (i.e. one button press latches and "arms" the circuit, while a second button press switches the final current...the latch can be disengaged if necessary and "de-arm" the circuit). Link to comment Share on other sites More sharing options...
mike_au Posted March 17, 2009 Share Posted March 17, 2009 I understood perfectly well what he meant, but the whole point is that if the receiver starts accepting stray signals as valid fire commands you are still not in charge of when it should go of. Hypothetically, you set up a charge in the woods consisting of 100 grams of flash. You set your timer and retreat to a safe distance where you can still keep an eye on it. As you are ready to press the button you see a group of children approaching the clearing where you have your charge, oops. They are going to have a picnic. So, do you still find it OK that a stray signal or atmospheric interference can set it off? Off course you can approach the charge and disarm it or tell the kids to get the F away from there but the chance for disaster is to high to risk it in my opinion. OK, but that is a complaint against wireless systems in general, not a problem with h0lx's timer idea (which is the post you quoted in your original message). If we assume that the person is going to be using a wireless system, then the timer could be a useful addition to that system. As for the wireless/wired debate, sure wireless will never be as secure and reliable as a hard wired system. It is up to the person running the show to decide if they are willing to trade a small amount of security for convenience and flexibility. Link to comment Share on other sites More sharing options...
andyboy Posted March 18, 2009 Share Posted March 18, 2009 I don't have a problem with wireless systems as long as they don't fire when they shouldn't. If a system will accept stray signals or interference as valid fire signals it doesn't matter how many extra security items that are connected, you are not in charge of when a piece will go off. In h0lx's example, there could be a fire signal on in the area that he has set up his charge in, when the timer has armed the device, BOOM. Would you say that he controlled the firing, arguably yes, by timer but not by remote. Then the remote is obsolete in this case, just use the timer. I don't have anything against remote detting, but I think that you should think twice about it. What happens if you get a dud when you try to set it of remotely? The charge is armed since the run-away-time is expired, but why didn't it go of? Is it your remote that's screwed up or is it the charge itself. Link to comment Share on other sites More sharing options...
h0lx Posted March 18, 2009 Share Posted March 18, 2009 (edited) I agree with you. It's not that I will build anything, I just suggested a safety feature. I myself still use my 50m of mains cable and a drill accu. EDIT: added a comma Edited March 18, 2009 by h0lx Link to comment Share on other sites More sharing options...
mike_au Posted March 19, 2009 Share Posted March 19, 2009 I don't have a problem with wireless systems as long as they don't fire when they shouldn't. If a system will accept stray signals or interference as valid fire signals it doesn't matter how many extra security items that are connected, you are not in charge of when a piece will go off. A wireless signal is just a radio wave. One radio wave transmitting a given signal on a given frequency using a given modulation is exactly the same as any other and therefore ALL wireless systems will accept a stray signal as a valid fire signal if the stray happens to be exactly the same as the legitimate signal. We use preambles, encoding, encryption, arm/disarm states, checksums and frequency hopping to reduce the chance of a stray signal being valid, but it will never be perfect. There is always going to be a chance (however small) that a wireless system will go off when it shouldn't. In h0lx's example, there could be a fire signal on in the area that he has set up his charge in, when the timer has armed the device, BOOM. Certainly this isn't the desired outcome, now describe the same situation, but without the timer...he set up his charge, turns on the receiver, BOOM. Neither situation is good but one is certainly less bad. Fortunately due to all the precautions we took (preambles, encoding...) both situations are incredible unlikely. Would you prefer a 1 in 10,000,000 chance of having a device go off 60 seconds after you leave the area or a 1 in 10,000,000 chance of it going off when you turn on the receiver? Would you say that he controlled the firing, arguably yes, by timer but not by remote. Then the remote is obsolete in this case, just use the timer. Yes, in the 1 in a 10,000,000 chance that the area is saturated with valid fire signals, the remote is obsolete however in 9,999,999 cases in 10,000,000 the remote is in control of the show and provides far better flexibility and safety than a simple timer. No one is advocating a timer as an alternative to a well secured wireless protocol, but no wireless protocol is ever going to be perfect and in the extremely unlikely case of it failing a timer will work as a final line of defense that gives you a slightly better chance of being at a safe distance when the failure occurs. I don't have anything against remote detting, but I think that you should think twice about it.Certainly, there are risks and they should all be considered before you start. You should also take as many precautions as possible to minimize the risks, including having the firing system disabled until you have time to reach a safe distance. What happens if you get a dud when you try to set it of remotely? The charge is armed since the run-away-time is expired, but why didn't it go of? Is it your remote that's screwed up or is it the charge itself. How is this any different to any other form of firing? What if you get a dud and light it with visco+QM? Was the visco kinked? or was the BM from a dud batch? was the QM tube pinched too tight? is the tube slowly smoldering? I don't know about other systems, but my wireless setup has an abort button which puts the receiver back into the "ignore everything" state, the only way to get it back to being armed is to reset the receiver. So in the event of a dud, you hit abort, wait the standard 10-20 minutes in case something is still smoldering and then walk up, turn off the receiver, disconnect the ematch, flood the mortar. Link to comment Share on other sites More sharing options...
andyboy Posted March 19, 2009 Share Posted March 19, 2009 A wireless signal is just a radio wave. One radio wave transmitting a given signal on a given frequency using a given modulation is exactly the same as any other and therefore ALL wireless systems will accept a stray signal as a valid fire signal if the stray happens to be exactly the same as the legitimate signal. We use preambles, encoding, encryption, arm/disarm states, checksums and frequency hopping to reduce the chance of a stray signal being valid, but it will never be perfect. There is always going to be a chance (however small) that a wireless system will go off when it shouldn't. A wireless doorbell doesn't have encoding encryption nor remotely (pun) anything like that. You have a different system and that's not what I was referring to to begin with. Yes, in the 1 in a 10,000,000 chance that the area is saturated with valid fire signals, the remote is obsolete however in 9,999,999 cases in 10,000,000 the remote is in control of the show and provides far better flexibility and safety than a simple timer. Wireless doorbells in Sweden signal at 868 Mhz or 27 Mhz, wireless cars at 27Mhz and wireless phones at 800-900Mhz. This gives that there could be a lot of interference in the given range, within range to set of the charge. How is this any different to any other form of firing? What if you get a dud and light it with visco+QM? Was the visco kinked? or was the BM from a dud batch? was the QM tube pinched too tight? is the tube slowly smoldering? A dud using fuse is a dud after an hour, no question. A "dud" using a wireless setup is a lot more unsafe, read my previous post. Link to comment Share on other sites More sharing options...
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