---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 06/18/14: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:28 AM - Re: LED Ghosting (eschlanser) 2. 06:52 AM - Re: LED Ghosting (Dennis Johnson) 3. 06:56 AM - Re: Re: LED Ghosting (Sprocket) 4. 07:30 AM - Fw: Re: LED Ghosting (Roger & Jean) 5. 07:51 AM - Re: Fw: Re: LED Ghosting (Robert L. Nuckolls, III) 6. 08:02 AM - Re: Re: LED Ghosting (Sprocket) 7. 08:18 AM - Re: Fw: Re: LED Ghosting (Roger & Jean) 8. 08:51 AM - Re: Re: LED Ghosting (Robert L. Nuckolls, III) 9. 09:10 AM - Re: Re: LED Ghosting (Robert L. Nuckolls, III) 10. 12:54 PM - Re: LED Ghosting (donjohnston) 11. 01:04 PM - Re: LED Ghosting (donjohnston) 12. 03:11 PM - Re: Off Delay Cabin Light (Eric M. Jones) 13. 04:05 PM - Re: Re: Off Delay Cabin Light (R&J. Curtis) 14. 04:10 PM - Re: Re: LED Ghosting (Robert L. Nuckolls, III) 15. 04:21 PM - Re: Off Delay Cabin Light (user9253) ________________________________ Message 1 _____________________________________ Time: 06:28:49 AM PST US Subject: AeroElectric-List: Re: LED Ghosting From: "eschlanser" donjohnston wrote: > > > "The engine analyzer people said it was designed for incandescent... " Here's a simple solution. Use an incandescent bulb such as this: http://tinyurl.com/kw8usxc Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425076#425076 ________________________________ Message 2 _____________________________________ Time: 06:52:47 AM PST US From: "Dennis Johnson" Subject: AeroElectric-List: Re: LED Ghosting I don't remember specifically which of your instruments has the ghosting problem. I'll tell you my story, which may or may not be relevant, but it may help others with a similar situation as mine. When I first powered up my instrument panel, the red warning light for my Grand Rapids EIS engine monitor glowed very dimly when the panel was powered up but the engine monitor was turned off. Ghosting went away when I turned the engine monitor on. Like you, I had replaced an incandescent light with an LED. On the bench, the ghosting seemed like a problem. However, I focused on other, bigger, problems and never got around to fixing the ghosting problem. By the time I completed my flight test phase, I understood that the ghosting was not a problem at all and maybe even a benefit. I turn the engine monitor on before engine start and leave it on until after engine shutdown. Since ghosting only occurs when the master switch is on and the engine monitor is off, I never see ghosting because the engine monitor is normally on whenever the master switch is on. I now consider ghosting, if I ever see it, to be a warning that I've forgotten to turn the engine monitor on. "It's not a bug, it's a feature." Good luck, Dennis ________________________________ Message 3 _____________________________________ Time: 06:56:48 AM PST US From: Sprocket Subject: Re: AeroElectric-List: Re: LED Ghosting .....so the relay option is looking pretty good right about now. As I mentioned, there is the simple brute force relay method, then the more complicated 'elegant' method.... Elegance is elusive. Vern =================================================== Sent from my iThing. It is responsible for all gramma and typo terrors. > On Jun 18, 2014, at 6:27 AM, "eschlanser" wrote: > > > > donjohnston wrote: >> >> >> "The engine analyzer people said it was designed for incandescent... " > > > Here's a simple solution. Use an incandescent bulb such as this: http://tinyurl.com/kw8usxc > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=425076#425076 > > > > > > > > > > ________________________________ Message 4 _____________________________________ Time: 07:30:34 AM PST US From: "Roger & Jean" Subject: Fw: AeroElectric-List: Re: LED Ghosting I submitted this a couple of days ago and it seemed to be ignored. Does anyone know why this very simple method would not work?? Perhaps you could use a zener with a voltage just slitely higher than the open circuit off voltage output. Put that in series with the LED, to block the small output, and reduce the series resistor to bring the brightness up. Roger ________________________________ Message 5 _____________________________________ Time: 07:51:09 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: Fw: AeroElectric-List: Re: LED Ghosting At 09:29 AM 6/18/2014, you wrote: >I submitted this a couple of days ago and it seemed to be >ignored. Does anyone know why this very simple method would not work?? > > Perhaps you could use a zener with a voltage just slitely > higher than the open circuit off voltage output. Put that in > series with the LED, to block the small output, and reduce > the series resistor to bring the brightness up. Not sure what you're suggesting . . . can you offer a schematic along with some description of where the voltage drops are expected and of what magnitude? Bob . . . ________________________________ Message 6 _____________________________________ Time: 08:02:58 AM PST US From: Sprocket Subject: Re: AeroElectric-List: Re: LED Ghosting Dimming wouldn't work very well with an in series zener. Vern ========================== ========================== Sent from my iThing. It is responsible for all gramma and typo terrors. > On Jun 18, 2014, at 7:29 AM, "Roger & Jean" wrote: > > I submitted this a couple of days ago and it seemed to be ignored. Does a nyone know why this very simple method would not work?? > > Perhaps you could use a zener with a voltage just slitely > higher than the open circuit off voltage output. Put that in > series with the LED, to block the small output, and reduce > the series resistor to bring the brightness up. > > Roger > > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > ________________________________ Message 7 _____________________________________ Time: 08:18:05 AM PST US From: "Roger & Jean" Subject: Re: Fw: AeroElectric-List: Re: LED Ghosting Perhaps you could use a zener with a voltage just slitely higher than the open circuit off voltage output. Put that in series with the LED, to block the small output, and reduce the series resistor to bring the brightness up. Not sure what you're suggesting . . . can you offer a schematic along with some description of where the voltage drops are expected and of what magnitude? I am not familiar with the device outputing the signal to the LED. Perhaps I am all wet in assuming these outputs, See attached. Roger ________________________________ Message 8 _____________________________________ Time: 08:51:03 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: LED Ghosting At 08:52 AM 6/18/2014, you wrote: I don't remember specifically which of your instruments has the ghosting problem. I'll tell you my story, which may or may not be relevant, but it may help others with a similar situation as mine. When I first powered up my instrument panel, the red warning light for my Grand Rapids EIS engine monitor glowed very dimly when the panel was powered up but the engine monitor was turned off. Ghosting went away when I turned the engine monitor on. Like you, I had replaced an incandescent light with an LED. On the bench, the ghosting seemed like a problem. It was a legacy practice in aviation annunciator lamp outputs to offer some way that an annunciator can tell the pilot that the system driving that annunciator is OFF. Using the normally closed contacts of a relay ALWAYS works but if they can be replaced at less cost, the solid state option is preferred. The output circuit depicted in the adaptation of LED's to the B&C LR series regulators http://tinyurl.com/cgnwr5k is an exemplar approach to the task for incandescent annunciators common to the time. The resistor between the collector and base of the lamp driver causes a 'powered down' LR3 to drive an annunciator lamp into partial conduction . . . In later years we added a remote sense lead to the ov/lv detection system which causes the lv warn to come alive when the bus becomes hot but before the engine is started and irrespective of the position of the alternator field switch. This change of architecture eliminated the value of 'powered down' conduction of the annunciator sorta went away. The 'problem' can be eliminated by snipping out the one-time-useful resistor. I think I'll suggest that B&C eliminate that resistor in future production and modify any regulators that come back for other reasons. However, I focused on other, bigger, problems and never got around to fixing the ghosting problem. By the time I completed my flight test phase, I understood that the ghosting was not a problem at all and maybe even a benefit. It CAN be eliminated . . . with a massaging of performance facts . . . I turn the engine monitor on before engine start and leave it on until after engine shutdown. Since ghosting only occurs when the master switch is on and the engine monitor is off, I never see ghosting because the engine monitor is normally on whenever the master switch is on. I now consider ghosting, if I ever see it, to be a warning that I've forgotten to turn the engine monitor on. "It's not a bug, it's a feature." . . . it may have been just that under alternative design goals. Without benefit of documentation or conversation with the original designer . . . its a WAG. Bob . . . ________________________________ Message 9 _____________________________________ Time: 09:10:05 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: LED Ghosting > > >I suggest we pay homage to our teachers one of whom once replied: >"Dammit Bob, I'm a doctor, not a engineer" -Dr. Leonard McCoy- > >Unfortunately, this is a bit beyond my skillset. While the squiggly >lines are not quite hieroglyphics to me, I'm not exactly sure what >to do with them. > Not sure how to answer this . . . analysis and resolution of some problems simply does not move forward without good data. Putting a resistor across the lamp/resistor string SHOULD have fixed your problem. But the narrative of your observed behavior left me scratching my head . . . too much is not yet known . . . Emacs! Bob . . . ________________________________ Message 10 ____________________________________ Time: 12:54:58 PM PST US Subject: AeroElectric-List: Re: LED Ghosting From: "donjohnston" [quote="nuckolls.bob(at)aeroelect"] > > Not sure how to answer this . . . analysis and > resolution of some problems simply does not > move forward without good data. > > Putting a resistor across the lamp/resistor > string SHOULD have fixed your problem. But the > narrative of your observed behavior left > me scratching my head . . . too much is > not yet known . . . > > Bob . . . Technically the resistor did fix the problem (ghosting). But it created a new problem (dim LED). So now I'm working on the second problem while not re-introducing the first problem. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425094#425094 ________________________________ Message 11 ____________________________________ Time: 01:04:07 PM PST US Subject: AeroElectric-List: Re: LED Ghosting From: "donjohnston" eschlanser wrote: > > donjohnston wrote: > > > > > > "The engine analyzer people said it was designed for incandescent... " > > > Here's a simple solution. Use an incandescent bulb such as this: http://tinyurl.com/kw8usxc You are right, it is a solution. Just not very simple. Since I would have to scrap the circuit board that the LEDs are mounted to and design a new one. And since this is a incandescent bulb, it would have to be socketed. Which means redesigning the warning panel assembly to be deep enough to accept the new light bulb. Not sure how I would handle replacing the bulb when it burns out though. Or I could just scrap the whole warning panel altogether. Then I'd have to fill in that rectangular hole in the panel, drill holes for the 8 warning lights. Come up with the circuit design for the new warning lights. etc., etc., etc., Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425095#425095 ________________________________ Message 12 ____________________________________ Time: 03:11:40 PM PST US Subject: AeroElectric-List: Re: Off Delay Cabin Light From: "Eric M. Jones" > I prefer simpler designs and hope to publish one here soon, using no ICs and only six basic parts. It will do a "slow-fade dim-out". As promised, here is a basic Sexy Slow-Fadeout Cabin Light that is very rugged and very simple. I uses only six basic parts. The main high-current switch is a LM395 Indestructible Power Transistor, but any number of other NPN power transistors would do just fine. The timer stays on for about R x C seconds, which here is 32 seconds. You can change this as you like preferably with a higher-value resistor (because it's easier). The transistor needs some heatsinking if you want it to dim a very big bunch of LEDs. But some experimenting will determine what you need. Two notes: 1) The previous "De-Slumpifier" also works well for this task, and you don't need any "keep-alive" bus. 2) Cree sells 200/lumen per watt white leds now, so don't be stuck with the antiques ones if you can use these. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425098#425098 Attachments: http://forums.matronics.com//files/lamp_fade_out_timer_441.pdf ________________________________ Message 13 ____________________________________ Time: 04:05:04 PM PST US From: "R&J. Curtis" Subject: Re: AeroElectric-List: Re: Off Delay Cabin Light Eric, my computer says Page not found when I try to open the attachment. Roger ________________________________ Message 14 ____________________________________ Time: 04:10:18 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: LED Ghosting > > >Technically the resistor did fix the problem (ghosting). But it >created a new problem (dim LED). So now I'm working on the second >problem while not re-introducing the first problem. That's the fact that does not make sense. The barefoot string of two LEDS and a resistor function with a current level on the order of 15 to 20 milliamps. (First sketch in the document I published). This is much lower than the typical incandescent lamp at 80+ milliamps. Adding the resistor (second sketch) adds another 12 to 14 milliamps for a total of 27 to 34 milliamps . . . much LOWER than the incandescent lamp being replaced. We can continue to flog this topic with all manner of cut, paste, try, suppose, wish and propose . . . with poor prospects for fixing it and poorer prospects for understanding root cause for the symptoms you've observed. The second sketch 'fix' should have NO effect on lamp intensity . . . the fact that it does have an effect says we don't know squat about what we're doing . . . yet. Hence, the 'dim LED' is a mystery that cannot be resolved without knowing the reason for what appears to be a reduction of available voltage. The experiments I asked you to conduct went toward resolving the mystery. Bob . . . ________________________________ Message 15 ____________________________________ Time: 04:21:43 PM PST US Subject: AeroElectric-List: Re: Off Delay Cabin Light From: "user9253" Thanks Eric, the download worked for me. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=425106#425106 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.