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Indicator light circuit with push to test

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donjohnston

Joined: 13 Dec 2009
Posts: 231

Posted: Sun Jun 09, 2013 4:15 am Post subject: Indicator light circuit with push to test

I'm working on an annunciator panel circuit that will have a push-to-test function and dimmer. No problem there. 



The challenge that I'm having is that some of the indicators will be powered by the line which drives the device (pitot heat, fuel pump, etc.) and others will be switched to ground. 



I'd be fine if it weren't for the push-to-test function.

JOHN TIPTON

Joined: 17 Sep 2006
Posts: 239
Location: Torquay - England

Posted: Sun Jun 09, 2013 5:42 am Post subject: Indicator light circuit with push to test

There are push (to test) switches out there that are two (double) pole - use

one to power circuit, and one to earth circuit:



Here are a few:

http://www.e-switch.com/product/tabid/96/productid/60/sename/mdp-16-series-modular-pushbutton-switch-interchangeable-actuators/default.aspx



John



---

Bob McC

Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

Posted: Sun Jun 09, 2013 6:00 am Post subject: Indicator light circuit with push to test

Don;



You indicate that "push to test" is no problem for you, but you're

struggling with the opposite polarities. One method would be to duplicate

whatever circuitry you intend to connect all of your indicators together to

accomplish the push to test on the other side of those lamps which are

switched opposite. Use a double pole "push to test" button with one pole

switching the "live" side lamps and the other pole switching the "ground"

side lamps.



Bob McC



[quote] --

_________________
Bob McC
Falco #908
(just starting)

sprocket(at)vx-aviation.c
Guest

Posted: Sun Jun 09, 2013 8:16 am Post subject: Indicator light circuit with push to test

Here's what you need:

http://store.makerplane.org/annunciator-controller-il-4a-kitset/



This design provides for active high or active low inputs, push to test and 

supports the connection of an external dimmer for night ops.



Vern



--

graeme.hart(at)onecoolkat
Guest

Posted: Mon Jun 10, 2013 12:00 pm Post subject: Indicator light circuit with push to test

If you are sitting in the plane on the ground doing pre-flight checks I hope you would notice if  the landing gear was not down! 

On Tue, Jun 11, 2013 at 4:23 AM, John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)> wrote:

 [quote]--> AeroElectric-List message posted by: John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)>

  

 That is certainly true, but if my landing gear "down light" doesn't come on, I'd like to be able to at least verify that the bulb is or isn't working.

 

 John Grosse

 

  	  Quote: 	
		   Robert L. Nuckolls, III <mailto:nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

 June 11, 2013 9:33 AM

 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

 

 



    Is it not better to test a warning system by

    watching for annunciation of a real stimulus

    like low pressure, unlocked canopy or low

    voltage . . . as opposed to knowing that the

    lamp is good?

 

 

   Bob . . .

 

 



	
 

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[b]

grosseair(at)comcast.net
Guest

Posted: Mon Jun 10, 2013 12:39 pm Post subject: Indicator light circuit with push to test

Gee, really? The situation I was imagining would be in the air, on 

approach, but on the ground you would be right:)



Do you happen to remember Eastern 401 that crashed in the Everglades 

while the crew tried to figure out if the gear light was burned out. A 

"push to test" function would have been handy to have.



John



Graeme Hart wrote:

 	  Quote: 	
		  

 If you are sitting in the plane on the ground doing pre-flight checks 

 I hope you would notice if  the landing gear was not down! 



 On Tue, Jun 11, 2013 at 4:23 AM, John Grosse <grosseair(at)comcast.net 

 <mailto:grosseair(at)comcast.net>> wrote:



     

     <grosseair(at)comcast.net <mailto:grosseair(at)comcast.net>>



     That is certainly true, but if my landing gear "down light"

     doesn't come on, I'd like to be able to at least verify that the

     bulb is or isn't working.



     John Grosse

endspeed(at)yahoo.com
Guest

Posted: Mon Jun 10, 2013 1:25 pm Post subject: Indicator light circuit with push to test

Or maybe the simpler solution is two juxtaposed indicator bulbs wired in parallel.

On Jun 10, 2013, at 3:39 PM, John Grosse <grosseair(at)comcast.net> wrote:

 	  Quote: 	

 Gee, really? The situation I was imagining would be in the air, on approach, but on the ground you would be right:)

 Do you happen to remember Eastern 401 that crashed in the Everglades while the crew tried to figure out if the gear light was burned out. A "push to test" function would have been handy to have.

 John

 Graeme Hart wrote:

> 

> If you are sitting in the plane on the ground doing pre-flight checks I hope you would notice if  the landing gear was not down! 

> 

> 

> 

> On Tue, Jun 11, 2013 at 4:23 AM, John Grosse <grosseair(at)comcast.net <mailto:grosseair(at)comcast.net>> wrote:

> 

>    

>    <grosseair(at)comcast.net <mailto:grosseair(at)comcast.net>>

> 

>    That is certainly true, but if my landing gear "down light"

>    doesn't come on, I'd like to be able to at least verify that the

>    bulb is or isn't working.

> 

>    John Grosse

graeme.hart(at)onecoolkat
Guest

Posted: Mon Jun 10, 2013 2:04 pm Post subject: Indicator light circuit with push to test

Good point, we were obviously thinking of quite different situations.

 

With an LED "light" the chance of it failing is minute.  It is much more likely the sensor on the gear or the wiring will fail and a "push to test" function would do nothing to help in this situation.

 

 On Tue, Jun 11, 2013 at 8:39 AM, John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)> wrote:

 [quote] --> AeroElectric-List message posted by: John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)>

Gee, really? The situation I was imagining would be in the air, on approach, but on the ground you would be right:)

 

Do you happen to remember Eastern 401 that crashed in the Everglades while the crew tried to figure out if the gear light was burned out. A "push to test" function would have been handy to have.



John

 

Graeme Hart wrote:

  	  Quote: 	
		   

If you are sitting in the plane on the ground doing pre-flight checks I hope you would notice if  the landing gear was not down! 





 On Tue, Jun 11, 2013 at 4:23 AM, John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net) <mailto:grosseair(at)comcast.net (grosseair(at)comcast.net)>> wrote:

 

    --> AeroElectric-List message posted by: John Grosse



    <grosseair(at)comcast.net (grosseair(at)comcast.net) <mailto:grosseair(at)comcast.net (grosseair(at)comcast.net)>>  



    That is certainly true, but if my landing gear "down light"

    doesn't come on, I'd like to be able to at least verify that the

    bulb is or isn't working.



     John Grosse

	
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[b]

sprocket(at)vx-aviation.c
Guest

Posted: Mon Jun 10, 2013 4:38 pm Post subject: Indicator light circuit with push to test

I think there is a bit of focus on testing the lamps.  Itâ€™s not the  only function for the PTT function.

 I use the PTT to set the dimmer level for night operations.  Press the  button, dial in the light level you want and you wonâ€™t be dazzled when a warning  lamp comes on.

  

 Vern

    

  From: Graeme Hart (graeme.hart(at)onecoolkat.com) 

 Sent: Monday, June 10, 2013 3:03 PM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: Re: Re: Indicator light circuit with  push to test

  



 Good  point, we were obviously thinking of quite different  situations.

 

With an LED "light" the chance of it failing is  minute.  It is much more likely the sensor on the gear or the wiring will  fail and a "push to test" function would do nothing to help in this  situation.



 On Tue, Jun 11, 2013 at 8:39 AM, John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)> wrote:

  	  Quote: 	
		     --> AeroElectric-List message posted by: John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)>

Gee, really? The    situation I was imagining would be in the air, on approach, but on the ground    you would be right:)



Do you happen to remember Eastern 401 that crashed    in the Everglades while the crew tried to figure out if the gear light was    burned out. A "push to test" function would have been handy to    have.



John



Graeme Hart wrote:

    	  Quote: 	
		       

If you are sitting in the plane on the ground doing      pre-flight checks I hope you would notice if  the landing gear was not      down! 





     On Tue, Jun 11, 2013 at 4:23 AM, John Grosse <grosseair(at)comcast.net (grosseair(at)comcast.net)      <mailto:grosseair(at)comcast.net (grosseair(at)comcast.net)>>      wrote:



    --> AeroElectric-List message posted by:      John Grosse



    <grosseair(at)comcast.net (grosseair(at)comcast.net)      <mailto:grosseair(at)comcast.net (grosseair(at)comcast.net)>>      



    That is certainly true, but if my      landing gear "down light"

    doesn't come on, I'd like to      be able to at least verify that the

    bulb is or isn't      working.



    John Grosse

	
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_ities    such as List    Un/Subscription,

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href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List

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Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Tue Jun 11, 2013 5:22 am Post subject: Re: Indicator light circuit with push to test

Push-to-Test circuits are testament to the poor reliability of tungsten filament lamps. They are not needed in LED systems. Granted, some allowance could be made if it made sense, but it would be a stretch to think of one.



One design note: The enormous decrease in the cost of tiny video systems means they could be put almost anywhere. Think of the possibilities:



Fire detection,

Ice detection,

landing gear position and lock condition,

In-tank fuel level indication,

rear traffic monitor,

FLIR 

Binocular altitude detection.

There are endless possibilities. Anyplace you would like to see can now be seen.

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

donjohnston

Joined: 13 Dec 2009
Posts: 231

Posted: Tue Jun 11, 2013 5:52 am Post subject: Re: Indicator light circuit with push to test

 	  Quote: 	
		  I think there is a bit of focus on testing the lamps.  Itâ€™s not the  only function for the PTT function.

 I use the PTT to set the dimmer level for night operations.  Press the  button, dial in the light level you want and you wonâ€™t be dazzled when a warning  lamp comes on. 	




Awww. Crap!  I didn't think about dimming.   



How the heck am I going to be able to dim all the indicators with a single knob? I used Eric's EGPAVR for panel and interior lights. And that would work with the ground switched indicators, but not the device driven indicators. 



BTW, After reading the responses, I've elected to forgo the PTT function. The indicators will be tested by activating the associated devices.

stuart(at)stuarthutchison
Guest

Posted: Tue Jun 11, 2013 6:22 am Post subject: Indicator light circuit with push to test

Kinda like the F-35, which employs a Distributed Aperture System (DAS) to

amalgamate video in the pilot's helmet for vision past the airframe in all

directions.



Yes, imagine if you could peer inside the fuel tanks ... yay!  Although,

this will probably become affordable just before the demise of fossil fuels

& electrolyte won't be quite so entertaining 



Kind regards, Stu



F1 Rocket    VH-FLY       http://www.mykitlog.com/RockFLY

www.teamrocketaircraft.com



--

sprocket(at)vx-aviation.c
Guest

Posted: Tue Jun 11, 2013 7:14 am Post subject: Indicator light circuit with push to test

.. That's why I developed the IL-4A lamp controller in 2004.  Now available 

from MakerPlane.  It supports the dimming and ptt for both active high and 

active  low signals...



Vern



--

sprocket(at)vx-aviation.c
Guest

Posted: Tue Jun 11, 2013 4:13 pm Post subject: Indicator light circuit with push to test

It's all there: http://107.22.231.30/redmine/projects/il-4a/documents



Thx, Vern



--

donjohnston

Joined: 13 Dec 2009
Posts: 231

Posted: Fri Jun 14, 2013 9:27 am Post subject: Re: Indicator light circuit with push to test

 	  sprocket(at)vx-aviation.c wrote: 	
		  It's all there: http://107.22.231.30/redmine/projects/il-4a/documents



Thx, Vern



-- 	




Looks like this is for 12v systems.  I'm running a 24v system.

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