Draco_Americanus Posted March 11, 2010 Posted March 11, 2010 I have been working on a micro controlled remote system but one question i have been having is what would i use to make a pyrogen for the ignighters? I find lots of kits but no one says what the chemicals are? any ideas? sofar i have the remote and transmitter working, for safty they brodcast a digital id code and if that matches with the reciver's code the command to fire is carried out. I am trying to fashion the transmitter to look like a remote device that was widely used in the stargate sg1 tv series, I think i can do it but it will be a tight fit and i would need to use a lithium ion battery beacuse of size constrants, but anyway i will try to be more active and get back into thye swing of things. it's nice to be back
dagabu Posted March 11, 2010 Posted March 11, 2010 How about this one? Potassium Chlorate 20 Lampblack, conductive 5 Antimony Trisulfide, Dark Pyro Al, 325 mesh 5 http://passfire.com/images/clear.gif http://passfire.com/images/clear.gif Tare: http://passfire.com/images/clear.gif Total: 30 Add a small dollop of NC lacquer and thin with acetone. You want as little NC as you can get away with, because it is an insulator. Strip the ends of your wires, dip them in slurry, hang up to dry. After about an hour, dip them once more. Finish off with a dip in straight NC lacquer or PVC pipe cement. You can add a pinch of aluminum or fine Ti to the mix for sparks. (I don't because a lot of what I do needs a very dark ignition to not interfere with the effect, but for most fireworks purposes a large ball of sparks would be desirable.) These pop easily on 9V and will go off reliably with as little as 4V but not on a single AA battery.
Bonny Posted March 12, 2010 Posted March 12, 2010 I'm assuming you are looking for a bridgeless pyrogen? There are a few other formulae on Alan Yates page www.vk2zay.net/composition. If not though, and you are using a bridge wire, plain old BP + pinch of Al or MgAl works great. Beware that BP will eat away nichrome in several months to a year.
mike_au Posted March 12, 2010 Posted March 12, 2010 Slightly OT, but just be careful with those radios. Most if not all of the 433MHz units I have seen use a simple ASK modulation which is extremely susceptible to noise. Although most people would be using their firing system a fair distance from things like cordless phones, laptop computers, etc one radio transmitter that a lot of people carry around with them is a keyless entry/immobiliser remote for their cars, and a lot of these operate at 433MHz. You mention transmitting an ID, which is a good start, but do you do any sort of checksumming (at least a parity bit, if not a full 8bit XOR or even a 32bit CRC) ? Is there any way that one or two bit-flips could convert a "disarm" command into a "fire" command? I am also a fan of having an "abort" command that will irreversibly disable the system until a hard reset, just so there is no chance of it receiving a stray "fire" while you are walking up to it.
gordohigh Posted March 24, 2010 Posted March 24, 2010 Will the bridgeless mathches really go off on as little as 4 volts? Reason I ask is I just got a 6 cue expandable system and the individual que's have 4 aa batterries in each box and when at full charge are slightly over 6 volts. If I could use that formula, (with the conductive lamp black), it would sure save some time and hair pulling. BTW, is all lamp black conductive, being that it is carbon I would say yes as carbon fiber rc helicopter blades do conduct, found that out when putting some leds for night flying on it. I am greatly interested in this subject. If you do a bridged e-match, you would not need the lamp black and I would guess raise the Antimony Trisulfide?
Mumbles Posted March 24, 2010 Posted March 24, 2010 Not all lampblack is conductive. Lampblack is generally produced on a commercial scale with a special furnace from petroleum or coal tar. The normal grades are not conductive. You can make conductive lampblack from burning an extremely fuel rich acetylene flame. You need the higher temperature to give a somewhat graphitic structure. I've tried to convert charcoal to a more graphitic structure by heating significantly with a gas flame in a crucible for about 20-30 hours, but to little effect.
gordohigh Posted March 24, 2010 Posted March 24, 2010 OK, good to know. I guess I need to put that on my want list so I can try the bridgeless ematch to see if my system will work with it. I remember looking at this on firefox I believe.
Mumbles Posted March 24, 2010 Posted March 24, 2010 I'll try to look up the info for you, but you can make bridgeless e-matches with other compositions. I know one person used a simple dip of graphite in NC lacquer, and then BP over the top. It worked, but there was a bit of lag. I've often thought about the use of BP or sulfurless BP mix with graphite replacing the charcoal. I've also heard that high aluminum comps could also be a potential replacement. Alan Yate's website potentially have a few mixed not based on conductive lampblack.
dagabu Posted March 24, 2010 Posted March 24, 2010 (edited) I think that was me. It takes a lot of power to get the graphite to arc. Conductive lamp black is horrible to work with but once you mix a few ounces, you will be set for life. It takes significantly less amperage to light the lamp black. IMHO Not to railroad the thread but I found nichrome wire and pyrogen ignited by a old flash unit from a disposable camera to work great at distance. Edited March 24, 2010 by dagabu
Mumbles Posted March 24, 2010 Posted March 24, 2010 It's was a guy named Frogfot, who is from Finland. The site is down, but there is an archive. http://web.archive.org/web/20080610140257/http://www.frogfot.com/pyro.html#elig
Arthur Posted March 24, 2010 Posted March 24, 2010 I have used the igniter chips from ODA with great success. Get the 50gauge chips and they become as close as possible to commercial ematches. The dip I use is 47.5% antimony trisulphide, 47.5%KClO3 and 5% nitrocellulose. Method mill chlorate to pass 200 mesh, mill separately SbS to pass 200mesh. Mix chlorate with NC and add acetone then stir, then add antimony tri sulphide. Keep the mixture runny but like thick syrup. Make up less than half a gramme at a time and dispose of the surplus before it dries. H3 chlorate and charcoal seems to work also adhered with NC and acetone. If you must use bridgeless then you may need to find acetylene black to get conductivity and CMC to get things to stick together in a conductive way.
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