Replacing lamp with LED in Estes Launch Controller

[LeeR]

I've seen comments in another thread about using a low current LED in launch controllers to prevent accidental firing of Quest's new Q2G2 igniters. I just bought a 10mm blue LED at Radio Shack that is nearly a perfect fit in the Estes controller. This LED is rated at 20mA, so it is well below the Q2G2 firing current of 120mA. It has a forward voltage of 3.2 to 3.8V, so a 470 ohm current limiting resistor is fine.

For anyone wanting to try this, and not really comfortable trying to figure out what values of resistors to use, check out http://www.ledcalc.com

This site tells typical voltages required for different color LEDs, and depending on whether you are using 6, 9, or 12V, you just plug in your numbers and it tells you what resistor to use.
It also tells what power rating needed, but 1/4 watt is going to be the case for most situations. A pack of 5 resistors is 99 cents at Radio Shack.

I used Radio Shack's model 276-0006 LED, since I wanted blue, but red and green LEDs are cheaper. The package gives current and voltage ratings, so it is easy to figure out what you need with this website utility.

I have not finished the conversion, I've only hooked up the LED and resistor to a 12V gel cell to test it. I'll post pictures when I complete it -- probably this weekend.

[shrox]

I've seen comments in another thread about using a low current LED in launch controllers to prevent accidental firing of Quest's new Q2G2 igniters. I just bought a 10mm blue LED at Radio Shack that is nearly a perfect fit in the Estes controller. This LED is rated at 20mA, so it is well below the Q2G2 firing current of 120mA. It has a forward voltage of 3.2 to 3.8V, so a 470 ohm current limiting resistor is fine.

For anyone wanting to try this, and not really comfortable trying to figure out what values of resistors to use, check out http://www.ledcalc.com

This site tells typical voltages required for different color LEDs, and depending on whether you are using 6, 9, or 12V, you just plug in your numbers and it tells you what resistor to use.
It also tells what power rating needed, but 1/4 watt is going to be the case for most situations. A pack of 5 resistors is 99 cents at Radio Shack.

I used Radio Shack's model 276-0006 LED, since I wanted blue, but red and green LEDs are cheaper. The package gives current and voltage ratings, so it is easy to figure out what you need with this website utility.

I have not finished the conversion, I've only hooked up the LED and resistor to a 12V gel cell to test it. I'll post pictures when I complete it -- probably this weekend.


You could just buy a Quest controller. It's already got an LED and a pleasant beep. And it fires Q2G2s.

[mycrofte]

Will the Quest controller fire Estes igniters too?

[Ltvscout]

Will the Quest controller fire Estes igniters too?
Absolutely.

[Shreadvector]

The wording would have been clearer if he said that the Quest controller will *not* accidentally fire any igniter during continuity check.

When you hit the launch button, it will fire almost any igniter using the internal 9volt alkaline battery. If you use the "EBC" and a bigger battery you can fire anything. The launch leads are much thicker than the Estes wires, so there is less resistance. I'm going to check the delivered amperage during launch with various batteries when I have the time.

If you really must re-use the old fashioned Estes controller, you can install a plug in LED replacement lamp and it will then only pass 30 mA during continuity check and it will be safe for the Q2G2.

http://www.pinballlife.com/index.php?p=product&id=1174&parent=192

Absolutely.

[BEC]

Will the Quest controller fire Estes igniters too?
I did some measurements on current delivery of a Quest controller and two Electron Beams - one modified very similarly to what Lee is planning to do. Results are here: http://www.oldrocketforum.com/showpost.php?p=75102&postcount=22 I was surprised at how much current that little 9V Duracell delivered for a short time.

On the other hand, I think it would make much more sense to use the Quest external battery connector hooked to a 6-cell RC car NiCd pack or something larger if you were going to do a bunch of launching in one session. While the little 9V can deliver the necessary current it certainly isn't going to be able to do it as many times as even four alkaline AAs could (as in the stock or LED-modded Electron Beam controller). Battery capacity is battery capacity after all.

I now have made some leads up so I could actually fire some igniters and capture the data with my PA Pro. I should do a Solar, a Q2 and a Q2G2 to see how they compare.

[LeeR]

You could just buy a Quest controller. It's already got an LED and a pleasant beep. And it fires Q2G2s.
I am not sure I see you point -- why would anyone ever buy a perfectly acceptable solution when one can bash a different brand at considerably greater expense?

:chuckle:

OK, I own a Quest controller, but I wanted to go to even greater pain and modify an Estes one for 12V as well as the change to an LED. I like the Quest controller, I like the Quest pad, too. And I've read so much good news about the Q2G2s, that I'm looking forward to trying them out as well.

And you might appreciate this, being at Quest.

I bought a Moon Mutt at Walmart, and it was missing half the parts for the pad. Estes Customer Service finally just sent me a whole new starter set, after about 2 months of trying to figure out what I needed (or not figuring it out). But, they did fix the problem in a very reasonable way. But I now have more Estes controllers than I know what to do with. Figured a conversion to LED was a fun project to do.

[mycrofte]

Being a "purest", I'll burn in hell before I give up my Estes Electron Beam! That, and a $1.50 bulb is a bit cheaper than a new controller...

Thanx for the link Fred!

Now, if they would just make the Quest engines the same size as Estes, I would use them. Who was the bonehead that decided to make them a different size anyway. There used to be a term in this country called "standardization". The first thing an engineer wants to do is re-invent the wheel...

[Bob Kaplow]

Now, if they would just make the Quest engines the same size as Estes, I would use them. Who was the bonehead that decided to make them a different size anyway. There used to be a term in this country called "standardization". The first thing an engineer wants to do is re-invent the wheel...

Huh? I've had no problems using Quest motors in my fleet. Some of the paper wraps are a bit tight, but some of the swelled Estes motors are a bit tight.

[luke strawwalker]

You could just buy a Quest controller. It's already got an LED and a pleasant beep. And it fires Q2G2s.

See, that's the kind of thinking that has gotten NASA in so much trouble... "Let's build a whole new pair of rockets that only look like they use shuttle parts, but are really about 95% brand new" and cost accordingly. :D

Nope, "lets see what we can do with what we have" was never on the radar screen...

Works the same in model rocketry...

Course, you work for a 'contractor' so it's in your best interests for us to buy new controllers.... :D

Course I probably should get a Quest controller-- they kinda remind me of the missile firing switch in the movie "Crimson Tide"...

Can I get mine with Gene Hackman's voice saying "Missile Ready?? FIRE ONE!!!" when I pull the trigger??? That would be WAY COOL... :chuckle:

Later! OL JR :)

[mycrofte]

Huh? I've had no problems using Quest motors in my fleet. Some of the paper wraps are a bit tight, but some of the swelled Estes motors are a bit tight.

We bought some Quest 'B' engines last spring and had to tape every one of them to fit into Estes rockets. So, I can only guess you are shooting Quest rockets if they fit OK. Or I had an odd batch...