Parts to convert Estes controller for Quest ignitors

[Marc_G]

Hi folks,

A while back I posted a thread ("Whip it good") that touched on cluster ignition details. Along the way, it came up that one can convert an Estes yellow launch controller (Electron Beam) to use Quest ignitors by switching out the bulb for an LED and adding another resistor to make the current appropriate for continuity check without pre-firing the low-current Quest ignitors.

I'm now at the point where I may be using Quest ignitors and am looking for the Radio Shack or similar store part numbers to buy to accomplish this. I could probably eventually figure out the details but I figure you guys have done this lots before.

Thanks in advance for suggestions.

Marc

 

[TheAviator]

You really don't need parts numbers. Rat Shack usually has a set of parts drawers all laid out, just open it and see what they have. You want to use a green or blue LED as they show up best during the day and are usually brighter. Just pick one of the ultra-bright green or blue LEDs and 180 ohm or 390 ohm resistor (20mA max and 10mA max, respectively). You could probably go a little lower on the resistor values, but I'm just giving you a safe estimate. If you want to, get a LED holder and mount it to the case, otherwise, just wire it in there. Just make sure you get the polarity of the LED correct.

 

[shreadvector]

Y0u do not need to buy and LED and resistor and solder anything.

Simply buy a direct replacement LED as i have recommended in several threads in the past. Here it is again (so we can refer to it in the future when people ask this common question again):

https://www.rocketryforum.com/showpost.php?p=107217&postcount=6

All the superbrights I've seen are VERY easy to see in bright sunlight. They are SUPERbright.

For plain old Estes controller lamp replacement, I've been using these:

Website is down during their move, but save this for later:
https://www.pinballlife.com/
https://www.pinballlife.com/index.php...174&parent=192

Another source is:
https://www.centsibleamusements.com/p...led-44-47.aspx

 

[BEC]

Having done this conversion both the Rat Shack way and the Pinball Life way, I have to say the latter is MUCH simpler. Both work.

It looks to me like Pinball Life's site is back up - perhaps they have completed their move....

 

[Marc_G]

guys,

Thanks. I've bought what I need at rat shack... the direct replacement way would definitely be much better but I was looking to get this done this weekend and didn't want to wait for mail order, nor possibly deal with shipping charges or minimum orders.

I'll give it a whirl and see how it goes. Thanks for the help!

Marc

 

[Marc_G]

One last question. Is the resistor I bought IN PLACE OF the one in the stock controller or IN ADDITION TO it? I bought two resistors... one about 400 Ohm and one about 200 Ohm.

Marc

 

[Trident]

[/URL]

One last question. Is the resistor I bought IN PLACE OF the one in the stock controller or IN ADDITION TO it? I bought two resistors... one about 400 Ohm and one about 200 Ohm.

Marc

The stock controller should just have a light bulb in it -- not sure about your comment on a resistor in the stock controller. The LED and current limiting resistor replace the continuity lamp. Incandescent bulbs pull lots of current, so the LED/resistor combo provide a low drain alternative for checking continuity, and are therefore safe for low current igniters like the Quest Q2G2.

Go to https://ledcalc.com, and it will tell you the value of the current limiting resistor to use. You need to know the current you want (usually 20mA), and the forward voltage of the LED (both specified on the LED's packaging). Different color LEDs can have differing forward voltages. I bought a Rat Shack monster blue LED, and the forward voltage was 3.8V, with 20mA nominal current. For my controller, which I kept at 6V, you will have (6-3.8) V, across that resistor. Divide that by 20mA, (2.2 V divided by 20mA), which gives you 110 ohms, so I picked up a 100 ohm resistor (the program will up it to 120 ohms to reduce the current below 20mA, I chose to go a little more). For 12V setup, plug in accordingly. And the ledcalc.com site does all this for you.

 

[Marc_G]

Thanks! For some reason I thought the Estes controller had both a bulb and a resistor, rather than relying on the resistance of the bulb. Got it.

Marc

 

[Peartree]

The direct replacement LED bulbs are a swell idea. Is there anything additional that needs to be done it, while upgrading an Estes controller, you also want to change from the standard 6 V to a 12 V system? Would an additional limiting resistor then be necessary or would there be a different LED bulb selection?

 

[CharlaineC]

I like the derect bulbs as well I used a 150 ohm resister on my estes controler i converted to use my 24v baterypack

 

[Trident]

The direct replacement LED bulbs are a swell idea. Is there anything additional that needs to be done it, while upgrading an Estes controller, you also want to change from the standard 6 V to a 12 V system? Would an additional limiting resistor then be necessary or would there be a different LED bulb selection?

Peartree,

See my post two above yours. The direct replacement choice is simple, and you will pick either a 6V or 12V LED. But you are pretty much limited to those choices. You may want to run off a NiCad pack, maybe 7.2V, or 9.6V, or even higher (I've heard of people using cordless drill batteries much higher than 12V). In that case, the direct replacement style is not a solution. Although a bit more complicated, the bare LED applications are the most flexible, but you will need that current limiting resistor. The forward voltage spec and current rating are the key pieces of data. In my example, the LED I chose will have 3.8V across it, and the supply voltage therefore needs to be at least 3.8V, or it will not light. Obviously you want to pick something readily available, and 6V and 12V are logical choices. For a 6V, or 12V supply, that extra voltage would burn up the LED rated for 3.8V, so you use a current limiting resistor. If the LED has 3.8V across it, then the extra voltage ends up across that resistor. So if you know that you want 20mA max flowing through the circuit during continuity check (typical rating of many LEDs, and also safe for the low-current igniters), then the resistance needed is V/I -- voltage divided by current (which is ohms). And again, you are not limited to 6 or 12V. If you used a battery combo consisting of two 7.2V RC NiCad packs, then you would have 14.4 V total, which gives you 10.6V across the resistor. That would translate to 530 ohms resistance required. But 530 ohms is not a value available for 5% resistors, so you'd go to 560 ohms (therefore safely limiting the current to slightly less than the 20mA). Try out the website I mentioned -- it is pretty handy if you want to go the bare LED route.

Now, you could also make a controller dual voltage -- maybe 6V using the 4 AA batteries in the Estes controllers, and then an extra cable to run it off your car's 12V battery. A switch, and two different resistors, and you could have a dual voltage model.

Hmmm, I think I'll convert mine!

 

[Marc_G]

Hi guys,

I'll do a build thread tomorrow if I have time, but I'll report here that I've successfully converted a spare Electron Beam controller using a Radio Shack 276-006 LED (blue, ultrabright something like 8000 millicandle) and a 330 Ohm resistor.

I did some tests with first one Q2G2 and was pleased when it didn't fire the ignitor on continuity check, but I got a nice bright blue light. Hooked up 3 of them with a whip, and all was still well. Hit the Fire button and all thre ignitors flared instantaneously.

Took it out to the field and tried my Big Green Max with 3x C6-3. Left the pad like a bat out of hell. I spent a few hours in recovery efforts getting it out of a tree somewhat outside the primary recovery zone. Tried local materials (sticks, not high enough), went to Home Depot (PVC pipes, but poking at it didn't help) and eventually went home, got big stepladder and a hook, and pulled it down. Snapped the kevlar cord somehow... But Got 'er back! Confirmed all three motors fired. Equivalent of 2 D motors. Hee hee.

Unfortunately, I thought I had video but apparently screwed up. Sigh. Wouldn't have been much to see... it teleported off the pad and was next seen about 800 feet up, and climbing.

Marc

 

[bobkrech]

Marc was asking for information on converting the Estes launcher for Quest Q2 igniters.

The Quest igniters have an all-fire spec of 120 ma. Generally accepted safety practices limit the continuity current to about 1/10 of this value or ~12 ma, so some of the solutions presented here would allow higher currents to be present.

The voltage drop across a standard ultrabright LED range from about 2 volts for red to about 3.5 volts for blue and white. A 1000 ohm 1/8 watt resistor in series with any led will limit the loop current to ~10 ma with 12 volt batteries or 5 ma with 6 volt batteries. Any clear ultrabright LED will be readily visible in sunlight at these currents.

Bob

Correction: The Q2G2 all-fire current is 350 ma, and the no-fire current is 120 ma accoridng to the Quest website. Based on this information, the continuity current should not exceed 35 ma: 1/10 the all-fire current and well below the no-fire current to extend battery life.

 

[Marc_G]

Thanks Bob,

This is good info. I had thought I was shooting for no more than 20 mA; didn't realize I needed to be down at 12 mA.

Still I think I'm OK. Check my math; maybe I missed something.

The LED I used (RS 276-006) has a voltage drop of 3.8v (that's what it's rated at, at least). If I assume that my 4x AA battery set gives 6 V, that means I've got 2.2 V to handle at 12mA. If V=IR, with V of 2.2 V and I of .012 Amps, R comes out to 183 Ohms.

Since I'm up at 330 Ohms, isn't that enough to spare?

OR, is it that by bringing down the current, I also reduce the V drop over the LED? If this is what's happening, then indeed it's down to about 2.3 V. That leaves 3.7 Volts to kill via resistor, which at 12 mA works out to 308 Ohms. So my 330 Ohm resistor should be safe, even if I'm slightly above the rated 6V.

This is fun recreational mathematics for me! If I've missed something please let me know.

Marc

 

[Marc_G]

Hi folks,

Here's a mini-build-sub-thread for converting a spare Electron Beam launch controller for the Q2G2 ignitors. First a few disclaimers and so forth:
-I'm not an expert. I'm relating what I did, not telling you what you should do. Anything you do is at your own risk.
-When I was a kid I was I was kind of a whiz with electronics and such but that was 30 years ago.
-For stuff like this it's my nature to plan a little and then play it by ear. Be kind!
-The idea of using a direct replacement LED that goes in is an obviously great idea but I didn't feel like ordering stuff and waiting for it to come. Also, as you'll see, there would still have been a bit of work to doing it that way.

I'm not sure how to insert pictures inline with the text on this board so I'll do this over a few posts.

OK. First, I'm using as the basis for this build the standard yellow Electron Beam controller that comes in the starter sets. I unscrewed the battery door screws and found that the rest of the works inside were not immediately accessible. They are glued in behind a plastic cover.

To remove this plastic cover I inserted a screwdriver in a little gap near where the positive battery terminal contact is. I levered it up a bit, then used a sharp mat knife (new blade) to cut the bonded plastic joint for the length of the long axis. Every few millimeters I repositioned the screwdriver I was using to pry up a bit more plastic. A steady hand and sharp blade let me cut the whole length of the controller. After that I turned 90 degrees and did the same thing to cut the short side, after which the remaining glue failed and I was able to remove the cover, exposing the guts.

Sorry, I didn't take a picture at this stage.

With the electronics exposed, I could see it was pretty basic in there. A bulb and some sheet metal bits with a little joint for the launch key to make contact across. Should be pretty easy to retrofit.

The parts I used were from Radio Shack:
The Ultra Bright Blue LED part 276-006
Part of an LED holder part 276-080
330 Ohm resistor 271-1315

I unscrewed the screw holding the top metal contact plate that contacted the postive battery terminal. I removed this plate as well as a small yellow plastic ring that retains the bottom contact plate. The bulb is a bayonet-base thing that lives in a little plastic holder that slides in and out of the mount.

Now for an interesting revelation: for a typical user, if the bulb failed, there's no way to replace it short of cutting the controlle open. I assumed the clear bulb protector would twist off or some such but I found it is glued on. The only way to replace the bulb is to cut your way in like I did.

Anyway, I used the rubber lead spacer from the LED holder and slid it over the LED leads, pushing it all the way to the LED. I then built up its width with a strip of electrical tape I cut just slightly wider than the rubber thing. I used enough tape winds so that it now fits well in the bulb holder:

 

[Marc_G]

Having gotten this far, I then took the LED/rubber/tape assembly out of the metal plate.

I soldered the 330 Ohm resistor to the bottom of the metal plate that holds the bulb. I was worried the flux might not stick the solder to it very well but it actually grabbed right on once I got it hot enough with the iron.

Sorry for the blurry picture.

 

[Marc_G]

Next I mounted the LED (with the rubber/tape mount) into the plastic holder and made sure it fit well and was not too far up or down:

 

[Marc_G]

I placed the metal plate with the resistor on it over the mounted LED and then soldered the negative lead of the LED to the free lead of the resistor. I put a little bit of heat shrink tubing over most of the exposed lead wires.

 

[Marc_G]

Then I covered the resistor and the rest of the exposed leads with a slice of electrical tape and adjusted the position of the resistor so the plastic cover would eventually fit:

 

[Marc_G]

In the picture above, the exposed lead is the positive lead (it was the longer of the two on my LED).

I fit the top metal plate (the positive terminal contact plate) back on (having previously put back the little circle of yellow plastic), such that the positive LED lead went through the hole for the mounting screw. I screwed in the screw (tight fit due to the lead taking up room, but doable) and wond the lead around the screw before tightening it.

 

[BEC]

The Quest igniters have an all-fire spec of 120 ma. Generally accepted safety practices limit the continuity current to about 1/10 of this value or ~12 ma, so some of the solutions presented here would allow higher currents to be present.

Uh, Bob, this is what's on the Quest web site for Q2G2s:

TECHNICAL SPECIFICATIONS: No-Fire Current = 150mA, All-Fire Current = 350mA

My personal modified Electron Beam runs at 27mA with a fresh set of AAs and has never fired a Q2G2 without pushing the firing button.

The last time I measured an Electron Beam incandescent continuity light it was over 200 mA.

Marc: the most recent Electron Beams are sealed as you have described, which makes the replacement LED lamps from the pinball supply places cut-into-it exercise as you described. The older (say 18 months ago or more) black ones, or the older yellow with black printing ones have the removable bulb cover and the inside cover you had to pry off is not there, so these are real simple to do the pinball lamp way.

 

[Marc_G]

From there, it was just a bit of work to get the plastic cover back on. I didn't reglue it or anything. After I put fresh batteries in, and screwed the main cover back on, all was well. It held together nicely.

I next cut most of the original cable off, and substituted some solid 16 gauge speaker wire. I used the original small gauge stuff to make a whip with 3 sets of clips (eventually, will expand to 4 or 5). I made them 28 inches long, which was calculated to be a good length in the event I stake the line at the point where they split off. That would give them some travel but ensure they pull off before the rocket leaves the rail in the event of a non-firing engine in a cluster.

That all done, I tested it.

First, in my garage, I connected one Quest Q2G2 ignitor and inserted the launch key. Nice blue light from the LED (yes, I had tested it before in a mock up mode, but this was REAL). Noproblem with the ignitor prefiring. I left it for a few minutes in this manner actually, just to be sure it wouldn't gradually heat up and fire.

Then I connected 3 ignitors, one per whip end, and again was reqarded with blue light when I inserted the key.

Counted down and hit the fire key. All 3 fired simultaneously.

Here's video of the test:

[YOUTUBE]AGWwV3SBvlM[/YOUTUBE]

Emboldened, I went to my range and set up my Big Green Max with a triplet of C6-3 engines. It was windy (gusting to 10 miles per hour) but I wanted to see if it would work for a good launch.

I inserted the ignitors and plugged in the straws nice and tight. Really tight. Didn't seem like I would need any tape. See picture.

Waited for a break in the wind then hit the fire button. The thing took off like a bat out of hell. I thought I had the camera running but when I got home found no entry for it in the camera. Bummer. The rocket went up, and up, and up, with the ejection happening while it was still moving upwards at a nice clip. I use a streamer in this bird (3 feet by six inches) but even so the wind grabbed it and it landed outside my normal recovery zone. Took me 2 hours to get it out of a tree (several attempts with different implements). Eventually recovered it and here's a picture confirming all three lit, attached.

So, it's all good at this point. I'm quite pleased with how this worked out and grateful for all the help I've received here.

Wish me luck for future cluster flights.

Marc

 

[bobkrech]

Uh, Bob, this is what's on the Quest web site for Q2G2s:

My personal modified Electron Beam runs at 27mA with a fresh set of AAs and has never fired a Q2G2 without pushing the firing button.

The last time I measured an Electron Beam incandescent continuity light it was over 200 mA.

Marc: the most recent Electron Beams are sealed as you have described, which makes the replacement LED lamps from the pinball supply places cut-into-it exercise as you described. The older (say 18 months ago or more) black ones, or the older yellow with black printing ones have the removable bulb cover and the inside cover you had to pry off is not there, so these are real simple to do the pinball lamp way.

BEC

My mistake. You are indeed correct. The last time I looked it up, that information was not on the Quest wesite, and the value I gave was given on several of the forums IIRC.

As you stated, the published no-fire specification is 120 ma and the all-fire specification is 350 ma. https://www.questaerospace.com/itemdesc.asp?ic=7024B&eq=&Tp=

That being the case, most recommendations would use the all-fire current divided by 10 as the continuity current which would be 35 ma, although you can go as high as 120 ma according to the Quest information.

The Estes website lists the Estes lamp current at 0.25 amps which is twice the Q2G2 max-no fire current by less than the all-fire current. This is why the Q2G igniter usually fire when continuity tested on the Estes launcher.

Bob

 

[Marc_G]

I can't tell you guys how much I appreciate all the assistance I've gotten here. Without this forum, I'd be up a creek without a paddle!

Meanwhile it's nice to know I'm safe with the resistor I'm currently using.

 

[UhClem]

The Estes website lists the Estes lamp current at 0.25 amps which is twice the Q2G2 max-no fire current by less than the all-fire current. This is why the Q2G igniter usually fire when continuity tested on the Estes launcher.

The resistance of an incandescent light increases as it heats up so the initial current will be higher. I measured a resistance of 6 Ohms (excluding battery internal resistance) on my Electron Beam. When you add in the 3 Ohm Q2G2 resistance the initial current will be 6V/9Ohm = 2/3 Amp.