### Help Support The Rocketry Forum:

#### Steve

##### Well-Known Member
Is there a point to using both a continuity light and a buzzer? I finished building my first cluster (you'll never guess what it is ) and I don't want to depend on my otherwise reliable Electron Beam to light two engines in a model that kinda needs 'em both to fly straight - so I am in the process of building a 12v launch controller. Only I haven't decided on which to use, a buzzer or a light. So, I just wondered if there was any reason to go with both. Any thoughts?

Stephen

#### jflis

##### Well-Known Member
Personal preference, but i've always prefered a light. I don't see any real advantage to both, but either one works fine.

I think it boils down to preference. do you want to *see* or *hear* continuity?

jim

#### Steward

##### Well-Known Member

It's up to you....

And if you haven't noticed Bushrat...sorry for the delay in responding on that other thread...just did so...and it sounds like I'm just a little too late....

Sounds like you're on your way or almost finished building a controller...GOOD LUCK..and HAPPY FLYING...!!!

#### astrowolf67

##### Well-Known Member
I just built a 12V system not too long ago. I put both on mine. If I had just gone with one, it would have been the buzzer. Lots of times, the led can't be seen due to the brightness of the sun. With a buzzer, when you press the continuity button, not only you, but those around you can hear it, and will know the system is armed.

A

#### Austin

##### Guest
I use both a continuity LED and buzzer. The LED is at the launch controller and the bussers are at the pad. When armed and ready to fire, the buzzers turn on and are a good indicator for people that are setting up rockets on opposing pads or returning from fetching rockets to keep clear...you can hear them pretty well.

Another advantage is if one or the other fails due to wear or burnout, I still have a secondary means to check.

Carl

#### Micromeister

##### Micro Craftman/ClusterNut
TRF Supporter
I have both, with a toggle between, but I normally use the LED, the buzzer is just more noise and confusion during the countdown. It's a personal preferrence issue, as Jim mentioned either will work fine.

#### Steve

##### Well-Known Member
I suspected it's really a matter of personal preference. I might just go with the idea of installing them both, and toggle between. One more thing... I noticed some of you use a continuity button - is this for an extra level of safety? It would be easier to install now than to retrofit later.

BTW - Steward, I used the picture of your controller for my template, so if you happen to see mine and notice a resemblance... well, you know what they say about imitation and flattery and all that, right? (Who knew they had project boxes at Radio Shack®! Everybody but me, I guess).

Stephen

#### Stones

##### Well-Known Member
I have both. I agree with Carl on the "backup" type system. If one fails, the other still keeps you in the know. If I had to choose one it would be the buzzer. Especially for taking pics. Once you don't hear the buzzer at countdown, you better be pressing the button on the 'ol camera.

#### astrowolf67

##### Well-Known Member
On my controller, nothing is turned on when the safety key is inserted. All the key does is disconnect the battery when removed. After they key is inserted, then I can do a continuity check, by pressing a momentary button. Or, I can skip a continuity check, and press the launch button. I went with a seperate continuity button for two reasons. One, so the buzzer is not sounding through out the whole count down. Two, some low current e matches might ignite with a continuity check, which I would rather not happen while inserting the key. Johnnierkt can vouch for the sensitivity of a low current igniter system (does a certain 5x J cluster ring a bell?).

#### Steve

##### Well-Known Member
I have decided to install both a buzzer and a light, with the buzzer being switched. I attached a simple drawing of what I plan to do. Would it work?

Stephen

#### jflis

##### Well-Known Member
um... it *looks* like it would work, but man that's one convoluted schematic...

I did a quick sketch of what I *think* is the same wiring as in your schematic, but it's a little easier to see where the connections are going.

let me know if this helps.
jim

#### goose_in_co

##### Well-Known Member
looks like it would work fine to me, but might I make a suggestion?

Don't use the same connector for both the battery and the Ignitor clips.

That way there will be no confusion as what to plug where.

my 2 cents...

Goose

#### jflis

##### Well-Known Member
oohhh, good point. I never even notice that... yea, never use the same connector.

also (i've seen this MANY times and it drives me NUTS), don't use household outlets and such in your design. It's just too **** confusing and could lead to a serious problem if someone unfamilar with your use "plugs it in" to see what it does...

##### Well-Known Member
In a 12V system like that, what gauge wire (speaker OK?) would you use if you wanted about 5) feet?

Also, what gauge internal wiring?

(building one myself)

#### goose_in_co

##### Well-Known Member
What type of speaker wire?

I have seen everything from 22 AWG to 10 AWG used for speakers.

I would use 14-16 AWG wire, typically the stuff that you find used for lamp cords, it's cheap, easy to find (someone is always throwing away a lamp) and flexable.

What type of internal Wire?

It Depends on if it is carrying the igniter current or not. In Bushrat's diagram (use Jim's, it's easier to follow) Use the heavy wire from the battery to the igniter clips, and back to the battery. Lighter wire (22 AWG) can be used to connect to the continuity lamps and buzzers since they do not draw much power. The easy way to see where you need heavy wire is to press the launch button and then trace the power from the battery to the igniter and back to the battery, that will be where you need the heavy wire, the rest can be lighter gauge.

Goose

#### astrowolf67

##### Well-Known Member
Originally posted by jflis
oohhh, good point. I never even notice that... yea, never use the same connector.

also (i've seen this MANY times and it drives me NUTS), don't use household outlets and such in your design. It's just too **** confusing and could lead to a serious problem if someone unfamilar with your use "plugs it in" to see what it does...
Jim, my system uses house hold outlets for igniter lead outs. Only 39 cents each, and 25ft 16 guage launch cables from the dollar store for 3 bucks a set. Much cheaper than using banana jacks. More money saved to buy some more Fliskits

I do keep my cables put up where no one will get to them, in the same storage tote with my pads.

#### Stones

##### Well-Known Member
Looks like I'm guilty too Jim. I use a standard 3 prong "adapter" to plug in my 100' extension cord. Makes it easy to switch from the multi-pad to the rail pad. A phono plug to connect the igniter wires makes for a quick setup.

#### jflis

##### Well-Known Member
well, you see, it's a pet-peeve of mine...

I did that once too...

One day i'm in my shop refurbishing my club launch pads and controller and I needed more light so I plugged the lamp in...

...oh man...

you guessed it, i grabbed one of my pad leads instead of the lamp cord and pluged IT in... scared the beegeebers outta me, i gotta tell you! It could have been worse too. I could have been working on those leads at the time and had them in my hand.

anywho, it's just a peeve of mine. *i* certainly won't do it

#### goose_in_co

##### Well-Known Member
I have to agree with Jim.

As much as you keep your own stuff secure, all it takes is for someone's kid to grab one and plug it in, then you have a much bigger problem on your hands.

I understand the attraction to using AC Wall Outlets for launch pad connections, they are cheap, easy to get, reliable, and easy to use.

The one thing that I have learned in my years in the Electronics industry is that if there is a way for someone to mess it up and hurt themselves, they will.

##### Well-Known Member
How about using international plugs and outlets...of course you could never take it over seas....

#### Stones

##### Well-Known Member
Originally posted by Micromister
Jim I'm with you on the standard recepticle power plug and outlets.
another of my pet peeves is the phono plug, Mike is correct as the plug is inserted into the jack it is possible to short the plug out. not to mention the jack makes whatever it is installed in hot. ...
I gotta tell ya, I can't for the life of me, short a phono plug by inserting into the jack. If I turn it completely sideways and go out of my way to touch both the male and female surfaces of the plug to the jack, then it's possible. Unless you're using an unshielded jack, then that's another story. Also, igniters are never connected when inserting the plug and I believe there's no power there, until at least the continuity button is depressed, which is at the controller. I agree that there is always a "safer" way to do things but, I'm totally confident that the pad(s) I built are safe and work as designed. So there...

Btw...would love to check out the relay pic you posted but, alas, it's not very readable. Could you repost it in a higher rez, if possible?

#### jflis

##### Well-Known Member
Originally posted by Bushrat
Some really good advice. Thanks all. I was able to put everything together and it looks like it will work. Goose - very good tip on the connectors. I will definitely make some changes in that regard. Yes, Jim - your schematic is much easier to read than mine.

(By the way - if this message is full of misspellings and other errors, that's because my hand is sore from writing 10,000 times:"I promise I will never try and draw another electrical schematic as long as I live. ")

Now, I must sulk.

Stephen
LOL beleive me, that was NOT my intent!

just comes from a lifetime of sketching such things that turn into products... LOL

#### jflis

##### Well-Known Member
well, not all phono plugs are the same. Some are well insulated, some are not. Some are specifically make-before-break or break-befor-make, etc.

for my own stuff I usually use pretty high end components, but that comes from working in an engineering lab for nearly 20 years and having access to some *very* high end "scrap"...

*now* I have to look into a reliable, safe and functional version that uses more economy materials. it's a fine line to be walkin'

jim

#### goose_in_co

##### Well-Known Member
Stones...

I think that I know what your confusion is.

You are looking at an "RCA Phono Plug", which is what is used to connect your CD player (among other things) to your Stereo amplifier.

The other type is the "Phone Plug" which is also known as a 1/4" phone jack, or more commonly, the "large" Headphone jack/plug. On these the tip of the plug comes in contact with the ring on the receptacle when it is inserted. This was not an issue when they were designed for telephone switchboards back in the early 1900's, and it is not an issue for the headphones that you plug into your stereo, since the power is in your stereo. It coud be an issue for a launch controller, depending on how it is designed.

BTW Jim, good luck looking for parts, that is not an easy job.

Goose