Quest Q2 vs. Q2G2 igniters - firing current

[BEC]

I just got back from the monthly Boeing Employees Model Rocket Club launch (where we had a bunch of Scouts launching their first rockets, among other things).

I discovered the hard way the the club's large launch system is only partially safe for Quest igniters. The first time I hooked one up - a Q2 as supplied with the German-made A8-3s they are currently filling A6-4 orders with - with great care since I didn't know if the continuity light current would fire it. It didn't. I subsequently flew that one and another just fine.

I later racked up my Zenith II for its maiden launch with a German Quest B6-0 booster and Estes A8-5 sustainer. I used the supplied Q2G2 igniter in the B6-0....and the rocket took off when I flipped the toggle to check continuity. No one was too close and it was actually a nice flight, though the sustainer shed a fin somewhere - and all was recovered except that fin.

I obviously generalized too much about firing current between the two types of Quest igniters.

I subsequently flew another Q A8-3 with Q2 igniter and all worked as it was supposed to.

So....how much different is the all-fire current for the Q2G2 than the Q2?

[shockwaveriderz]

you might find this an interesting read on the Quest Q2 igniters:

http://psas.pdx.edu/Q2IgniterEvaluation/


as for thr Q2G2 read this thread:

http://www.oldrocketforum.com/showthread.php?t=4516

both should answer all your questions concerning the Quest Q2 and Q2G2 igniters.

HTH

Terry Dean

[BEC]

Terry,

That helps. In working the math backward from that first link, it looks as if the Q2s take similar amounts of current to fire as do Estes igniters. They concluded it took about 1Joule, or 1 watt-second of energy. If we assume their 100 ms fire time and, say, 6V, then we get about 1.7A fire current.

That would certainly correlate with what I observed on a launch system that was pretty much designed for Estes igniters and which was running off a 12V garden tractor battery yesterday.

The specs of the Q2G2 are available and I've participated in the other thread you linked to, so it was the Q2s that I really had the question about.

I'll just have to take a meter to the launch next month and measure the continuity current on that system - and not use Q2G2s on it any more.

[Mark II]

The Q2G2's (Quest igniter 2, generation 2) are the very first igniters that Quest has made that have a low all-fire current threshold. The previous generation Q2 igniters had firing current requirements that were similar to those of the Estes Solar igniter, as you noted. I don't know what the requirements were for the Tiger Tails (first generation igniters; hey, you might still run across them at some point - it could happen), but I suspect that they were the same as those for the Q2's and Estes igniters.

MarkII

[BEC]

Thanks.

I clearly misunderstood in the midst of all the info I've been absorbing since becoming BAR'd in January. Before that I wasn't even aware that Quest existed, never mind that they've had three kinds of igniters in their history, while during the 30+ years I've been out for Estes what were back then then brand-new Solar igniters are still the standard.

I will try to remember to take my good multimeter to the next BEMRC launch and actually measure the continuity current of their 5-pad setup.

[Shreadvector]

According to Quest, the "No-Fire" current is 50 mA and the "All-Fire" current is 150mA.


Replace the incandescent lamp ("bulb") for continuity with an LED that allows 30 or less mA to pass. Our club replaced ours with a very high light output LED that only passes 10 mA. It is ****ED bright.

[BEC]

Fred,

That would be the way to go....but I need to convince them it's needed first. I'm probably the first one that's ever shown up to one of their launches with a Q2G2 (or even a Q2). In the case of this particular launch setup it will be one replacement per channel - it has 10 or 12 (I don't recall). We were using five this past Saturday. Each one has a dedicated lamp and toggle switch for continuity checking/arming.

I use Q2G2 igniters myself primarily with an Electron Beam that is modified as you suggest (though it draws 27 mA on fresh cells). I also have a Quest controller from my Micromaxx starter set and it's in my field box as well.

[Shreadvector]

Fred,

That would be the way to go....but I need to convince them it's needed first. I'm probably the first one that's ever shown up to one of their launches with a Q2G2 (or even a Q2). In the case of this particular launch setup it will be one replacement per channel - it has 10 or 12 (I don't recall). We were using five this past Saturday. Each one has a dedicated lamp and toggle switch for continuity checking/arming.

I use Q2G2 igniters myself primarily with an Electron Beam that is modified as you suggest (though it draws 27 mA on fresh cells). I also have a Quest controller from my Micromaxx starter set and it's in my field box as well.

Definitely worth the modification.

From the Sept NAR Electronic Model Rocketeer:




Safety Note: Read the Instructions









Our hobby involves the use of high-energy propellants in high-velocity flight vehicles. If these are not used in the proper manner they could be unsafe, but in its 52-year history and in over 500 million flights the hobby has never had a fatal injury from handling or flying rockets. This is a tribute to the inherently safe design and construction features of model rockets and of model and high power rocket motors, and to general public awareness of and adherence to the NAR Safety Codes and other safety practices, even by consumers who have never heard of the NAR. How does this safety-critical public awareness and adherence happen? Through the instructions that accompany the rocketry products. People actually read these, and they actually provide accurate and useful information about safety.


It is easy to become complacent about your overall knowledge of the hobby after you've been doing it a while, and to believe that it is no longer necessary to read the instructions that come with common rocket products such as motors, igniters, etc.. This is not a good practice, particularly when you are using a new brand or model of an item. The new version may have some unique characteristics that require a different form of pre-flight handling or preparation in order for it to be safe. The manufacturer's instructions almost always describe this new characteristic and how to deal with it safely, but you have to read the instructions to find out!

As examples of why reading the instructions is important, some igniters fire on much lower current values than others and therefore cannot be used with launch systems using incandescent light bulbs for continuity testing. Some motors produce far more sparks than others and require very specific actions to prepare the launch area to avoid starting ground fires. Their instructions warn you of these features but rocket fliers continue to appear to be surprised by them.

It's more than OK to actually read the instructions the first time you use a product, it's a key element of safety!

[luke strawwalker]

I just got back from the monthly Boeing Employees Model Rocket Club launch (where we had a bunch of Scouts launching their first rockets, among other things).

I discovered the hard way the the club's large launch system is only partially safe for Quest igniters. The first time I hooked one up - a Q2 as supplied with the German-made A8-3s they are currently filling A6-4 orders with - with great care since I didn't know if the continuity light current would fire it. It didn't. I subsequently flew that one and another just fine.

I later racked up my Zenith II for its maiden launch with a German Quest B6-0 booster and Estes A8-5 sustainer. I used the supplied Q2G2 igniter in the B6-0....and the rocket took off when I flipped the toggle to check continuity. No one was too close and it was actually a nice flight, though the sustainer shed a fin somewhere - and all was recovered except that fin.

I obviously generalized too much about firing current between the two types of Quest igniters.

I subsequently flew another Q A8-3 with Q2 igniter and all worked as it was supposed to.

So....how much different is the all-fire current for the Q2G2 than the Q2?

The OLDER Q2's are virtually identical to the standard Estes ignitors and should have pretty much the same current requirements/continuity current limits.

The NEWER Q2G2's are much more current-sensitive and you need to be careful with those.

Always test a spare ignitor against any system you have doubts about to prevent 'continuity check launches'... :)

Later! OL JR :)

[BEC]

Always test a spare ignitor against any system you have doubts about to prevent 'continuity check launches'... :)

Later! OL JR :)

Yep.....clearly should've done that. And I would have had I not been confused about the Q2s and thinking that they and the Q2G2s had similar requirements. And even though the Q2s are "older" they are still being supplied today by Quest in two forms: undipped with Micromaxx engines and dipped with the German WECO A8-3s they are substituting for Chinese A6-4s as I've posted about in another thread.

And yes, I saw that bit in the Electronic Rocketeer. As previously noted, I was well aware of that but was mistaken about similarity between the two types.

Fortunately besides a group of startled onlookers and one lost sustainer fin, there were no real repercussions from the incident.

[Mark II]

Yeah, I'm surprised that Quest has gone back to bundling Q2's with their German-made motors. The Q2G2's must only come from their Chinese subcontractor.

MarkII

[BEC]

Yeah, I'm surprised that Quest has gone back to bundling Q2's with their German-made motors. The Q2G2's must only come from their Chinese subcontractor.

MarkII

Which is interesting, because Q2G2s are in with the German-made B6-0s I got in February from their big sale (one of which was the motor ignited prematurely on Saturday.....)

[Shreadvector]

Testing an igniter will not tell you 100% that the system is safe for that type of igniter because there is a RANGE of firing current. For the Q2G2 I listed the All-Fire and the No-Fire currents. If your system supplies a current inside that range, some may fire and some may not.

Since we know the specifications for the Q2G2, there is absolutely no need to guess: simply design the sytem (or retrofit) to deliver less than 50 mA during continuity. The LED I provided the link for drops the Estes Electron Beam continuity current to 30 mA and is WAYYY bright. Of course, if you are buying quest motors, then the simplest solution is to get a Quest controller. It delivers 10 mA and beeps. It delivers a lot of current when firing and if you use the EBC you can fire clusters instantly.

[MKP]

I may sound like a dolt here but I'll ask anyway. Whats the best way to test for mA? I've got a good multimeter, I know how measure ohms and volts, but I've never figured out amps.

[Shreadvector]

http://www.google.com/search?hl=en&q=measure%20current&btnG=Google+Search



http://scienceshareware.com/how-to-measure-DC-current-with-a-dmm.htm


When I use my $2.99 Harbor Freight meter, I use either the regular hole for the red lead for up to 200 mA or I switch the red lead to the 10A hole for measurements between 200 mA and 10A.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=90899
They are often on sale in the stores for $2.99.....


I may sound like a dolt here but I'll ask anyway. Whats the best way to test for mA? I've got a good multimeter, I know how measure ohms and volts, but I've never figured out amps.

[shrox]

Quest is going to publish a data sheet about our Q2G2 igniters.

Look for it in a few days, and it will be on our website.

[BEC]

While you're at it, how about a similar data sheet on the Q2s since you're supplying them with motors now as well?

[Ltvscout]

Quest is going to publish a data sheet about our Q2G2 igniters.

Look for it in a few days, and it will be on our website.
Please add a link to it in this post when it goes online. Thanks!

[shrox]

"DESIGNED FOR USE WITH THE QUEST 9V LAUNCH CONTROLLER - Please note that since they are very low current igniters (120ma fire current), some model rocket launch controllers can set them off during continuity tests. Be sure to test your model rocket launch controller, by connecting an igniter to your controller before inserting it into the model rocket engine to make sure it does not prematurely activate when you insert your safety key and/or when you perform a continuity check. "

Quoted from the Quest Aerospace site.

(Just look stuff up! It is the 21st century...)

[BEC]

<RANT>
Yes, yes, I KNOW THAT. I read that.

For the umpteenth time: I made a poor assumption that the Q2 igniters had equivalent characteristics to the Q2G2s and therefore a launch system which was OK for Q2s was OK for Q2G2s. I now know this is not correct. Before January of this year I didn't even know there WAS a Quest, never mind that they have had three kinds of igniters.

So: what are the official no fire and all fire currents for Q2 - NOT Q2G2 igniters? Or is "same as Estes Solar igniters" close enough?? THAT's what needs to be added to the Quest online info alongside the data that's already there for Q2G2s.

Since Quest is RIGHT NOW supplying BOTH types - and in the case of my recent engine order substituting one for the other - the information should be available for BOTH types.

Is that clear enough for all who have directly or indirectly told me "read the instructions"? Sheesh.

I am one of those weirdos who actually reads documentation. But I can't read what's not there. And I'd rather build and fly rockets (or airplanes) than conduct a test program for igniters with my limited modeling time.</RANT>

[shrox]

<RANT>
Yes, yes, I KNOW THAT. I read that.

For the umpteenth time: I made a poor assumption that the Q2 igniters had equivalent characteristics to the Q2G2s and therefore a launch system which was OK for Q2s was OK for Q2G2s. I now know this is not correct. Before January of this year I didn't even know there WAS a Quest, never mind that they have had three kinds of igniters.

So: what are the official no fire and all fire currents for Q2 - NOT Q2G2 igniters? Or is "same as Estes Solar igniters" close enough?? THAT's what needs to be added to the Quest online info alongside the data that's already there for Q2G2s.

Since Quest is RIGHT NOW supplying BOTH types - and in the case of my recent engine order substituting one for the other - the information should be available for BOTH types.

Is that clear enough for all who have directly or indirectly told me "read the instructions"? Sheesh.

I am one of those weirdos who actually reads documentation. But I can't read what's not there. And I'd rather build and fly rockets (or airplanes) than conduct a test program for igniters with my limited modeling time.</RANT>

The Q2 packaging says they work with "standard 6v or 9v launch systems", so is that helpful?
We will release the igniter datasheet soon, just has to be put together all pretty...

[BEC]

The Q2 packaging says they work with "standard 6v or 9v launch systems", so is that helpful?
We will release the igniter datasheet soon, just has to be put together all pretty...

Yes. I'm not sure that that information is in the bags with the WECO A8-3s or the Micromaxx motors but I may have missed it. I will look again when I get home.

[BEC]

OK - I checked the Quest documentation I could find. The little yellow pamphlet in with the WECO A8-3s describes how to install Q2s but doesn't really say anything about firing characteristics other than to say one should use a Quest launch controller (which makes sense - Estes docs say to use an Estes one after all...).

The paperwork from the Zenith II kit that got the surprise ride on Saturday describes how to install and use the older Quest "tiger tail" igniters. (I ordered this kit this past February). Of course the docs with the Quest B6-0s - which came to me in the same order and one of which I used in the Zenith II - describe how to use Q2G2s that were supplied with them.

I opened one of the Astra kits that came in the same order as the WECO A8-3s. There the info is about Q2G2s (as one would expect).

The instructions that actually came with my Micromaxx starter set from February describe something called a QMX igniter that I presume were in used prior to the (undipped) Q2s.

On the Quest web site there is nothing about Q2s except in context with Micromaxxes and there all it says is that they won't work with "the old silo style MICRO MAXX Launch system."

In short, I don't think I missed the words "standard 6V or 9V launch systems" since those words are not on any of the documentation I actually received nor in any obvious place on the Quest web site. Perhaps it's on packs of Q2s sold separately, but I've never actually seen such a package.

Maybe it's because I generally do read the documentation, especially on something that is new to me (like Quest motors/igniters), that these gaps in the docs bug me so.....

Enough of this, though. I have enough of an answer to my original query to know what to do now and what to advise the BEMRC to do with their launch system(s). I've already done what is needed for my own personal stuff.

And hopefully soon the available info on Quest igniters (and A motors) will match what is being shipped to customers.

[shrox]

https://www.discountrocketry.com/quest-rocket-engines/quest-igniters-pi-656.html?osCsid=db3bf98fd8d575c8d88ae26d08ff880d

Here's a pic of the package, you can barely read it, but here it is.

[luke strawwalker]

Yep.....clearly should've done that. And I would have had I not been confused about the Q2s and thinking that they and the Q2G2s had similar requirements. And even though the Q2s are "older" they are still being supplied today by Quest in two forms: undipped with Micromaxx engines and dipped with the German WECO A8-3s they are substituting for Chinese A6-4s as I've posted about in another thread.

And yes, I saw that bit in the Electronic Rocketeer. As previously noted, I was well aware of that but was mistaken about similarity between the two types.

Fortunately besides a group of startled onlookers and one lost sustainer fin, there were no real repercussions from the incident.

Well, it's certainly easy to get confused with as quickly as things change nowdays! The "Tiger Tails" were just coming out when I quit rocketry after high school, and I never got a chance to fly using any of them. I thought they looked like a neat idea, though. I guess they were the precursor of the "Copperheads" from the looks of them.

The Q2G2's are the cat's meow though IMHO. I made sure my systems were safe for them, and Dave our semiretired NAR advisor for the club made sure the club system was safe for them, because he likes clusters and they're just the cat's pajamas for clusters. I usually just use my own launcher though-- I'm funny that way. Anyway, with the dual jacketed wire leads they remind me of the E-matches and other sensitive ignitors used in HPR and DD systems, so that helps me remember they are current sensitive.

I got some older Q2's with some booster motors I ordered from Quest here while back, and I haven't used any yet, but they look like a better quality ignitor than the standard Estes issue ignitors. Estes are ok but not particularly durable because the tape lets go and lets the leads either bust the pyrogen or short out or both, and about 10-20% are just junk straight out of the package, which is pretty poor quality IMHO. The Q2's just seem a little more robust and better quality from what I've seen.

Later! OL JR :)

[luke strawwalker]

I think the confusion comes in because a system that is perfectly safe for continuity checks on an Estes ignitor is also fine for Q2's and Tiger Tails and other such similar ignitors, BUT they will 'fire' a Q2G2 when the key is inserted.

A system that perfectly fine for Q2G2's out of the box (the Quest controller among other MPR/HPR type systems, but NOT older bulb-type low impedence controllers like ALL Estes controllers) is also perfectly suitable for Q2's, Tiger Tails, and Estes ignitors, among others, and will not fire any of them on a continuity check.

Homemade systems like most clubs use may or may not be safe depending on their impedence and resulting current levels during the continuity check.

SO, I guess the answer is, "IT DEPENDS!" LOL:)

Generally speaking (very generally as I don't want to incur the wrath of Shreadvector) the ignitor's general construction should give a hint as to it's current sensitivity. Q2G2's are constructed similar to ematches and other HPR type ignitors, and are thus current sensitive. Q2's are constructed similar to Estes ignitors, which we know are NOT current sensitive. Tiger Tails and Copperheads are similar and fall somewhere in between...

clear as mud?? LOL:)

Good luck and if anybody ever gives you a straight answer with the actual current values, please post them here. I would if I had them.

Thanks! OL JR :)

[Mark II]

In the 4 years since I resumed my model rocketry hobby, I have seen Quest produce all five (!) of their igniter designs: Tiger Tails, QMX igniters (for the Micromaxx Silo launcher), Q2's, Q2G2's and finally the Micromaxx Igniter (a variant of the Q2 design). All new versions were welcome advances over the previous ones. (VERY welcome advances.) But rapid product development has the potential of confusing the consumer. BEC received a motor order that came with two different kinds of igniters, and no explanation of the difference between the two. That lack of explanation is where the problem occurred. In general, the changes have all been well-publicized and well-explained by Quest. There was simply a failure of communication, though, in this one order. The mistake (failure to include an explanation) occurred when the order was filled. Some of what followed was probably a consequence of that error.

Quest Aerospace is a very well-run and very responsible company. It enjoys great respect within the rocketry community. The two types of igniters in question, the Q2 and the Q2G2, are both very excellent products.

MarkII

[BEC]

Well, the varying types of igniters I've received (three types if you count the dipped and undipped Q2s as separate ones) have come over two orders, but the substitution of a different motor AND a different igniter type than what was expected from the description on their web site in the most recent order is partly to blame for my erroneous assumption about current equivalence. There was a little note saying I should expect similar performance from the motor, but nothing about the igniter "reversion" to Q2s. Also there is the mismatch between the documentation and the actual product received in the same order, since the kits' instructions describe Q2G2s.

I can understand wanting to use up rather than throw away existing documentation....but unless you assume the docs you send aren't read anyway (if so, why send 'em at all?), the instructions and the products should be consistent with one another.

The comment about e-matches and construction similarity is interesting. Were I active in composite motor use or HPR that would make more sense I suppose, but all I know of either is what I've read, mostly here, since late this past January. So I do know what's being referred to, but have no personal experience with any of that stuff.

As an aside, my failure rate on Estes igniters has been much lower than suggested above. I have had exactly one failure personally since Jaunuary and I have observed only a couple more that were clearly due to bad igniters (rather than bad installation of same) at one club launch. I've thrown away one igniter that was obviously bad right out of the package. That's it. I have an ever-growing supply of the Estes igniters since every WalMart motor pack has four igniters for three engines.

I have yet to experience a single failure of a Quest igniter (Q2G2, Q2 undipped or Q2) and in a couple of cases have been able to use the same undipped Q2 to launch more than one Micromaxx-powered flight. There is no doubt in my mind that they work very well.

[BEC]

I was at my local hobby shop earlier this afternoon. Their rocket section seems to be expanding - which is a good thing.

Anyway, there was quite a bit of Quest stuff - quite a bit more than they had last time I was there. This included three-packs of Quest motors hanging mixed in with the Estes ones. After pondering a bit, I picked up one of the bags of A6-4s. The package outside said that the engines were made in Germany and that it included Q2 igniters. When I got it home and opened it I found it DID have A6-4s (not A8-3s, which is what I expected since it was new stock). Instead it had the Chinese A6-4s and Q2G2 igniters inside (and the correct instructions for Q2G2s).

All of this is good except that's not what the bag said was in it. Now I'm sorry I didn't get a pack of C6-5s as I've been meaning to try the long-burn Cs - but the German/Q2 info on the bags made me figure that they'd be, well, the German ones. And since there was a bulk bag of A6-4s also on hand which visibly contained the black-nozzle German engines and Tiger Tail igniters (!) it certainly seemed plausible. I'll just have to go back and get a pack and see.

Clearly this is another case of using up existing stock - in this case engine packaging (the bags have the Arizona address for Quest on them, too) - but it sure is confusing when one has a specific desire. And I hope the bureaucrats don't get bent out of shape when the package says "made in Germany" and the contents are "made in China".

[luke strawwalker]

I was at my local hobby shop earlier this afternoon. Their rocket section seems to be expanding - which is a good thing.

Anyway, there was quite a bit of Quest stuff - quite a bit more than they had last time I was there. This included three-packs of Quest motors hanging mixed in with the Estes ones. After pondering a bit, I picked up one of the bags of A6-4s. The package outside said that the engines were made in Germany and that it included Q2 igniters. When I got it home and opened it I found it DID have A6-4s (not A8-3s, which is what I expected since it was new stock). Instead it had the Chinese A6-4s and Q2G2 igniters inside (and the correct instructions for Q2G2s).

All of this is good except that's not what the bag said was in it. Now I'm sorry I didn't get a pack of C6-5s as I've been meaning to try the long-burn Cs - but the German/Q2 info on the bags made me figure that they'd be, well, the German ones. And since there was a bulk bag of A6-4s also on hand which visibly contained the black-nozzle German engines and Tiger Tail igniters (!) it certainly seemed plausible. I'll just have to go back and get a pack and see.

Clearly this is another case of using up existing stock - in this case engine packaging (the bags have the Arizona address for Quest on them, too) - but it sure is confusing when one has a specific desire. And I hope the bureaucrats don't get bent out of shape when the package says "made in Germany" and the contents are "made in China".

Sounds like your LHS may have gotten some old stock... or else it's repackaged stuff...

Weird! OL JR :)

[John Brohm]

I've had the opportunity to conduct some quantified continuity tests with a number of available igniters. While the sample sizes used to conduct the tests were hardly statistically significant, I think the results are at least indicative of the performance we can expect, and provide some insight for those that may be planning or designing launch control and continuity check circuits.

My paper can be found at:

http://www.psc473.org/howto/Igniter.pdf

A special thanks to my good friend Doug Sams for his help in the preparation of the paper, as well as our esteemed Forum Moderator, Mr. Hansen, for providing his usual excellent editorial review.

[Rocketflyer]

Thank You, John. Good info. I printed it out and put into my binder.

[lmerdan]

Great paper John!

[brockrwood]

According to Quest, the "No-Fire" current is 50 mA and the "All-Fire" current is 150mA.


Replace the incandescent lamp ("bulb") for continuity with an LED that allows 30 or less mA to pass. Our club replaced ours with a very high light output LED that only passes 10 mA. It is ****ED bright.

Shoot, you stole my thunder! I was going to suggest just this approach. You can easily build your own launch controller (or you can hack the Estes controller) so that you use an LED and a resistor instead of a lamp. Wire the resistor in series with the LED (it doesn't matter which leg of the LED you hook the resistor to). The resistor limits the current to keep the LED from being zapped and, at the same time, keeps those feisty Quest Q2G2 igniters from firing!

The LED will show the "continuity" status while the resistor will only allow about 30 milliamps to pass through the igniter wires. A standard red LED (5 mm , a.k.a. "T 1 3/4" size) should work. To figure the value of the resistor, use this formula:

Resistance in ohms = (Supply voltage - voltage across resistor)/desired current in amps

A typical red LED will need about 1.8 volts to operate normally. The Estes controller provides 6 volts of supply voltage. The typical LED should get about 30 milliamps (.03 amps) of current to operate at a decent brightness level. The 30 milliamps through the circuit should be far less than the current required to fire a Q2G2 igniter.

In this case, the formula to determine the resistor's value looks like this:

R=(6-1.8)/.03
R=140 ohms

(If your controller supplies a different voltage, 9 or 12 volts, for example, replace the 6 volts in the equation with your controller's actual supply voltage.)

Use a resistor with a 1/4 watt or 1/2 watt power rating. If you can't find a resistor of exactly 140 ohms, just get as close as you can - a little higher is safer than a little lower. If the LED's brightness is too low (probably because of the resistance in the controller's wires, clips, and/or igniter itself) , you can decrease the resistor value a tad. Just test the hacked or homebrewed controller with an igniter or two before you use it to launch rockets.

Or you can just buy the Quest controller for about $16 and dispense with all this hacking nonsense!

- Brock

[LeeR]

According to Quest, the "No-Fire" current is 50 mA and the "All-Fire" current is 150mA.


Replace the incandescent lamp ("bulb") for continuity with an LED that allows 30 or less mA to pass. Our club replaced ours with a very high light output LED that only passes 10 mA. It is ****ED bright.

I modified an Estes Electron Beam controller with a very large, bright LED from RadioShack. The max draw on that LED, and many, is typically 20mA, so it is safe for Q2G2 igniters, and most low current igniters. Note: When you select a regular LED (one not specifically set up for a specific voltage, such as 12V), you must add a current limiting resistor. A good site for determining your need is www.ledcalc.com (http://www.ledcalc.com)


I also have an Electron Beam controller I modified for use at school launches. It uses 12V external battery, and I put a piezo buzzer on it for continuity checks. While kind of annoying to some, it is good in a group setting to give feedback to everyone that there is continuity, and launch is imminent. Piezo buzzers also are low draw, and I think the one I used was under 30mA - again safe for most low-current igniters.