---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 10/27/11: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:24 AM - Re: Z16 voltage concern (Robert L. Nuckolls, III) 2. 06:40 AM - Incandescent lamps in Wig-Wag systems (OOPS) (Robert L. Nuckolls, III) 3. 06:56 AM - Re: Z16 voltage concern (Sam Marlow) 4. 07:48 AM - Re: Z16 voltage concern (Jared Yates) 5. 08:40 AM - Re: Z16 voltage concern (Robert L. Nuckolls, III) 6. 08:59 AM - Re: Z16 voltage concern () 7. 09:03 AM - Re: Z16 voltage concern () 8. 09:43 AM - Re: Z16 voltage concern (Jay Hyde) 9. 10:33 AM - Re: Z16 voltage concern (user9253) 10. 10:34 AM - Re: Z16 voltage concern (Robert L. Nuckolls, III) 11. 11:05 AM - Re: Re: Z16 voltage concern () 12. 01:53 PM - AeroLeds (Robert L. Nuckolls, III) 13. 01:53 PM - Canopy Switch (user9253) 14. 04:24 PM - Audio Design (messydeer) 15. 04:47 PM - Re: Audio Design (Michael Welch) 16. 04:52 PM - Re: Audio Design (Michael Welch) 17. 04:57 PM - Re: AeroLeds (James Kilford) 18. 10:04 PM - Re: Audio Design (messydeer) ________________________________ Message 1 _____________________________________ Time: 06:24:54 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Z16 voltage concern At 01:41 AM 10/27/2011, you wrote: >Hello Les, > > >The problem comes from the diode between the Main Bus and the >Endurance bus; the forward voltage drop across this diode leaves you >with the lower voltage at the Endurance bus. When you put the >alternate feed on to the Endurance bus you 'boost' boost the voltage >because there is no diode in the alternate path. If you use a >Schottkey diode instead of a normal diode between the Main and >Endurance bus the Endurance bus voltage will be better as the >forward voltage drop across a Schottkey is less than that of a >normal diode, but you will always have a slightly lower voltage on >the Endurance bus. > >Jay My face is red. I should also have asked where you measured the system voltage. If measured on the e-bus in normal ops mode, the voltage will be a bit lower than the main bus . . . which doesn't matter. Recall that when the alternator is running and carrying all operating loads, the target voltage for the battery and main bus is 14.2 to 14.6 volts. This is the nominal supply necessary to top off your battery after an engine start. The e-bus, being fed through the diode WILL be down around 13.5 to 13.8 which is okay. Recall also that while a battery CHARGES at 14.2 to 14.6, it DELIVERS energy at 12.5 volts and BELOW . . . when it gets down to 10.5 volts, the battery is used up. If your e-bus accessories are chosen for their usefulness as aids to battery-only ops, then they're EXPECTED to perform over the battery only voltage range of 10.5 to 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no issues of concern. If your low voltage warning is built into an accessory attached to the e-bus, then it needs to trigger at some level which accommodates the diode drop. 12.8 volts is about right. If it is not user adjustable, then perhaps it should be disabled and a separate, standalone, LV warning set for 13.0 volts be driven from the MAIN bus. Finally, if push comes to shove, there's no sin in leaving the e-bus alternate feed switch closed during normal operations. The diode is there to prevent back- feeding the main bus should you find it necessary to revert to battery only operations. Sorry for the fire-drill. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:40:13 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Incandescent lamps in Wig-Wag systems (OOPS) A sharp eyed reader pointed out that I cited the wrong plot for a close look at inrush on the 55w lamp. The corrected citation has been substituted in the mini-essay below: At 10:30 AM 10/26/2011, you wrote: A few weeks ago I was called to task for some demonstrably sloppy data gathering when we were discussing inrush limiting on incandescent lamps used in wig-wag recognition systems. The plot I'd published at: http://www.aeroelectric.com/Pictures/Curves/Wig_Wag_Currents.jpg . . . was properly identified as somewhat 'fuzzy' and not properly supportive of some estimates of the cold start inrush values. I ran across my little po' boy's solid state switch yesterday so I drug it to the bench and set up the following experiment: http://aeroelectric.com/Pictures/Schematics/Test_Set-Up_Picture.jpg http://aeroelectric.com/Pictures/Schematics/Test_Set-Up_Schematic.jpg I ran some data plots with a 1 ohm resistor-load in place of the lamp. Here we observe the expected current flow plotted at scan speeds that will display 3-4 wig-wag cycles. http://www.aeroelectric.com/Pictures/Curves/1-OHM_250mS.jpg Then I zoomed in on an exemplar ON transition . . . http://www.aeroelectric.com/Pictures/Curves/1-OHM_50uS.jpg . . . and we see that the 'probe' connection is a tad bit over-damped as indicated by the rounding at the upper corner of the rise. I then replaced the load resistor with a 55w halogen head lamp bulb and produced this plot of wig-wag currents: http://www.aeroelectric.com/Pictures/Curves/55W%20WIGWAG.jpg Here we see the effects of lamp temperature on the inrush and running currents. At turn on, the lamp was cool enough to produce about a 9A spike. The measured current just before turn-off was on the order of 5A. Inrush current from a cold start is determined by total loop resistance of the wiring, battery source impedance, and lamp cold resistance. The lamp has a measured cold resistance of 145 milliohms. If driven by a zero-ohms source at 12v, the theoretical inrush would be 12/.134 = 83 amps. A slow sweep (1 mS/Div) peek at a cold start in this test setup yielded the following trace: http://www.aeroelectric.com/Pictures/Curves/55W_COLD-START_1mS.jpg Here we see a measured inrush on the order of 42 amps. This suggests that wiring and battery resistances added another 140 milliohms or so to the loop resistance. Zooming in for a closer peek at the cold start . . . (Corrected image citation) http://www.aeroelectric.com/Pictures/Curves/55W_COLD-START_50uS.jpg we see the same 42A displayed value for peak current. Further, there is still more rounding of the plot as compared with the almost purely resistive plot cited above. Exploration of lamp behavior during turn-on could not be conducted with a mechanical switch or relay. Contact bounce during turn-on would badly contaminate the data. The solid state switch driven by a function generator suffers no such shortcomings. The closer look confirms that my original suppositions for inrush on the trashy trace were correct. The earlier plot was made with longer wires than for this experiment hence we saw a 32A cold start inrush as opposed to 42A in this case. It also confirms that the dynamics for rate of rise and peak currents are limited by system wiring (resistance and inductance) and there were no erroneous observations limited by oscilloscope sample rates. This experiment supports my original assertions that turn-on transitions during wig-wag operations are a small fraction (about 25%) of the initial cold-start value. Bob . . . ________________________________ Message 3 _____________________________________ Time: 06:56:43 AM PST US From: Sam Marlow Subject: Re: AeroElectric-List: Z16 voltage concern Just wondered where I could find a Schottkey bridge to bring my voltage back up close to normal? Thanks, Sam Robert L. Nuckolls, III wrote: > > > At 01:41 AM 10/27/2011, you wrote: > >> Hello Les, >> >> >> >> The problem comes from the diode between the Main Bus and the >> Endurance bus; the forward voltage drop across this diode leaves you >> with the lower voltage at the Endurance bus. When you put the >> alternate feed on to the Endurance bus you 'boost' boost the voltage >> because there is no diode in the alternate path. If you use a >> Schottkey diode instead of a normal diode between the Main and >> Endurance bus the Endurance bus voltage will be better as the forward >> voltage drop across a Schottkey is less than that of a normal diode, >> but you will always have a slightly lower voltage on the Endurance bus. >> >> Jay > > My face is red. I should also have asked where you > measured the system voltage. If measured on the e-bus > in normal ops mode, the voltage will be a bit lower than > the main bus . . . which doesn't matter. > > Recall that when the alternator is running and carrying > all operating loads, the target voltage for the battery > and main bus is 14.2 to 14.6 volts. This is the nominal > supply necessary to top off your battery after an engine > start. > > The e-bus, being fed through the diode WILL be down around > 13.5 to 13.8 which is okay. Recall also that while a > battery CHARGES at 14.2 to 14.6, it DELIVERS energy > at 12.5 volts and BELOW . . . when it gets down to 10.5 > volts, the battery is used up. > > If your e-bus accessories are chosen for their usefulness > as aids to battery-only ops, then they're EXPECTED to > perform over the battery only voltage range of 10.5 to > 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no > issues of concern. > > If your low voltage warning is built into an accessory > attached to the e-bus, then it needs to trigger at > some level which accommodates the diode drop. 12.8 > volts is about right. If it is not user adjustable, > then perhaps it should be disabled and a separate, > standalone, LV warning set for 13.0 volts be driven > from the MAIN bus. > > Finally, if push comes to shove, there's no sin in > leaving the e-bus alternate feed switch closed during > normal operations. The diode is there to prevent back- > feeding the main bus should you find it necessary to > revert to battery only operations. > > Sorry for the fire-drill. > > Bob . . . > > ________________________________ Message 4 _____________________________________ Time: 07:48:52 AM PST US Subject: Re: AeroElectric-List: Z16 voltage concern From: Jared Yates Bob sells a nice package on the aeroelectric connection website. I installed his system and subsequently cooked the diode due to improper insulation in my mounting, and I was able to find the diode itself online separately for a few dollars. I would recommend Bob's package since it has the circuit board and mounting hardware ready to go. On Thu, Oct 27, 2011 at 9:53 AM, Sam Marlow wrote: > > > Just wondered where I could find a Schottkey bridge to bring my voltage back > up close to normal? > Thanks, > Sam > > Robert L. Nuckolls, III wrote: >> >> >> >> At 01:41 AM 10/27/2011, you wrote: >> >>> Hello Les, >>> >>> >>> >>> The problem comes from the diode between the Main Bus and the Endurance >>> bus; the forward voltage drop across this diode leaves you with the lower >>> voltage at the Endurance bus. When you put the alternate feed on to the >>> Endurance bus you 'boost' boost the voltage because there is no diode in the >>> alternate path. If you use a Schottkey diode instead of a normal diode >>> between the Main and Endurance bus the Endurance bus voltage will be better >>> as the forward voltage drop across a Schottkey is less than that of a normal >>> diode, but you will always have a slightly lower voltage on the Endurance >>> bus. >>> >>> Jay >> >> My face is red. I should also have asked where you >> measured the system voltage. If measured on the e-bus >> in normal ops mode, the voltage will be a bit lower than >> the main bus . . . which doesn't matter. >> >> Recall that when the alternator is running and carrying >> all operating loads, the target voltage for the battery >> and main bus is 14.2 to 14.6 volts. This is the nominal >> supply necessary to top off your battery after an engine >> start. >> >> The e-bus, being fed through the diode WILL be down around >> 13.5 to 13.8 which is okay. Recall also that while a >> battery CHARGES at 14.2 to 14.6, it DELIVERS energy >> at 12.5 volts and BELOW . . . when it gets down to 10.5 >> volts, the battery is used up. >> >> If your e-bus accessories are chosen for their usefulness >> as aids to battery-only ops, then they're EXPECTED to >> perform over the battery only voltage range of 10.5 to >> 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no >> issues of concern. >> >> If your low voltage warning is built into an accessory >> attached to the e-bus, then it needs to trigger at >> some level which accommodates the diode drop. 12.8 >> volts is about right. If it is not user adjustable, >> then perhaps it should be disabled and a separate, >> standalone, LV warning set for 13.0 volts be driven >> from the MAIN bus. >> >> Finally, if push comes to shove, there's no sin in >> leaving the e-bus alternate feed switch closed during >> normal operations. The diode is there to prevent back- >> feeding the main bus should you find it necessary to >> revert to battery only operations. >> >> Sorry for the fire-drill. >> >> Bob . . . >> >> >> >> >> > > ________________________________ Message 5 _____________________________________ Time: 08:40:45 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z16 voltage concern At 08:53 AM 10/27/2011, you wrote: > > >Just wondered where I could find a Schottkey bridge to bring my >voltage back up close to normal? >Thanks, Why are you worried about it? Given the physics of how the system is designed, 13.5 IS normal. The standard rectifier bridge will give you a drop of about .7 volts for a 10A e-bus load. The Schottky device will drop that to about .5 volts. Not a great difference. The acid test is to operate your airplane for a time with the e-bus alt feed switch open, and then for a time with it closed. Were it not for a reading on a display, would you know the difference? Know that bus isolation diodes are used on large aircraft. While these are usually 28 volt systems were the diode drop represents a smaller percentage of loss . . . the drop is noted, evaluated and found insignificant to normal operations of devices down- stream of the diode. I suggest that such is the case here as well. Bob . . . ________________________________ Message 6 _____________________________________ Time: 08:59:03 AM PST US From: Subject: Re: AeroElectric-List: Z16 voltage concern I'm aware of the Schottkey diode board but that's not a bridge. I need two sources in to feed my aux buss, so no switching is required. I have this setup now, but it drops the voltage to the 12v range, with the Radio Shack bridge setup. ---- Jared Yates wrote: ============ Bob sells a nice package on the aeroelectric connection website. I installed his system and subsequently cooked the diode due to improper insulation in my mounting, and I was able to find the diode itself online separately for a few dollars. I would recommend Bob's package since it has the circuit board and mounting hardware ready to go. On Thu, Oct 27, 2011 at 9:53 AM, Sam Marlow wrote: > > > Just wondered where I could find a Schottkey bridge to bring my voltage back > up close to normal? > Thanks, > Sam > > Robert L. Nuckolls, III wrote: >> >> >> >> At 01:41 AM 10/27/2011, you wrote: >> >>> Hello Les, >>> >>> >>> >>> The problem comes from the diode between the Main Bus and the Endurance >>> bus; the forward voltage drop across this diode leaves you with the lower >>> voltage at the Endurance bus. When you put the alternate feed on to the >>> Endurance bus you 'boost' boost the voltage because there is no diode in the >>> alternate path. If you use a Schottkey diode instead of a normal diode >>> between the Main and Endurance bus the Endurance bus voltage will be better >>> as the forward voltage drop across a Schottkey is less than that of a normal >>> diode, but you will always have a slightly lower voltage on the Endurance >>> bus. >>> >>> Jay >> >> My face is red. I should also have asked where you >> measured the system voltage. If measured on the e-bus >> in normal ops mode, the voltage will be a bit lower than >> the main bus . . . which doesn't matter. >> >> Recall that when the alternator is running and carrying >> all operating loads, the target voltage for the battery >> and main bus is 14.2 to 14.6 volts. This is the nominal >> supply necessary to top off your battery after an engine >> start. >> >> The e-bus, being fed through the diode WILL be down around >> 13.5 to 13.8 which is okay. Recall also that while a >> battery CHARGES at 14.2 to 14.6, it DELIVERS energy >> at 12.5 volts and BELOW . . . when it gets down to 10.5 >> volts, the battery is used up. >> >> If your e-bus accessories are chosen for their usefulness >> as aids to battery-only ops, then they're EXPECTED to >> perform over the battery only voltage range of 10.5 to >> 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no >> issues of concern. >> >> If your low voltage warning is built into an accessory >> attached to the e-bus, then it needs to trigger at >> some level which accommodates the diode drop. 12.8 >> volts is about right. If it is not user adjustable, >> then perhaps it should be disabled and a separate, >> standalone, LV warning set for 13.0 volts be driven >> from the MAIN bus. >> >> Finally, if push comes to shove, there's no sin in >> leaving the e-bus alternate feed switch closed during >> normal operations. The diode is there to prevent back- >> feeding the main bus should you find it necessary to >> revert to battery only operations. >> >> Sorry for the fire-drill. >> >> Bob . . . >> >> >> >> >> > > ________________________________ Message 7 _____________________________________ Time: 09:03:56 AM PST US From: Subject: Re: AeroElectric-List: Z16 voltage concern Your right Bob, I just wanted see normal, or as close to normal, as possible. It's a good dignastic tool. Is it possible to construct my own bridge using Schottkey diode's, or is that silly? ---- "Robert L. Nuckolls wrote: ============ At 08:53 AM 10/27/2011, you wrote: > > >Just wondered where I could find a Schottkey bridge to bring my >voltage back up close to normal? >Thanks, Why are you worried about it? Given the physics of how the system is designed, 13.5 IS normal. The standard rectifier bridge will give you a drop of about .7 volts for a 10A e-bus load. The Schottky device will drop that to about .5 volts. Not a great difference. The acid test is to operate your airplane for a time with the e-bus alt feed switch open, and then for a time with it closed. Were it not for a reading on a display, would you know the difference? Know that bus isolation diodes are used on large aircraft. While these are usually 28 volt systems were the diode drop represents a smaller percentage of loss . . . the drop is noted, evaluated and found insignificant to normal operations of devices down- stream of the diode. I suggest that such is the case here as well. Bob . . . ________________________________ Message 8 _____________________________________ Time: 09:43:26 AM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: Z16 voltage concern I could tell you where to find it in South Africa! :-) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HH Enterprises Aircraft assembly, repair, wiring and avionics Flight instruction General and Electrical Engineering services (NHD Elec Eng, BTech Elec Eng, GDE ELec Eng) Great dinner parties and conversation General adventuring, climbing, kayaking and living Blog: www.rawhyde.wordpress.com Cel: 083300 8675 Email: jay@horriblehyde.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Sam Marlow Sent: 27 October 2011 03:53 PM Subject: Re: AeroElectric-List: Z16 voltage concern Just wondered where I could find a Schottkey bridge to bring my voltage back up close to normal? Thanks, Sam Robert L. Nuckolls, III wrote: > > > At 01:41 AM 10/27/2011, you wrote: > >> Hello Les, >> >> >> >> The problem comes from the diode between the Main Bus and the >> Endurance bus; the forward voltage drop across this diode leaves you >> with the lower voltage at the Endurance bus. When you put the >> alternate feed on to the Endurance bus you 'boost' boost the voltage >> because there is no diode in the alternate path. If you use a >> Schottkey diode instead of a normal diode between the Main and >> Endurance bus the Endurance bus voltage will be better as the forward >> voltage drop across a Schottkey is less than that of a normal diode, >> but you will always have a slightly lower voltage on the Endurance bus. >> >> Jay > > My face is red. I should also have asked where you > measured the system voltage. If measured on the e-bus > in normal ops mode, the voltage will be a bit lower than > the main bus . . . which doesn't matter. > > Recall that when the alternator is running and carrying > all operating loads, the target voltage for the battery > and main bus is 14.2 to 14.6 volts. This is the nominal > supply necessary to top off your battery after an engine > start. > > The e-bus, being fed through the diode WILL be down around > 13.5 to 13.8 which is okay. Recall also that while a > battery CHARGES at 14.2 to 14.6, it DELIVERS energy > at 12.5 volts and BELOW . . . when it gets down to 10.5 > volts, the battery is used up. > > If your e-bus accessories are chosen for their usefulness > as aids to battery-only ops, then they're EXPECTED to > perform over the battery only voltage range of 10.5 to > 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no > issues of concern. > > If your low voltage warning is built into an accessory > attached to the e-bus, then it needs to trigger at > some level which accommodates the diode drop. 12.8 > volts is about right. If it is not user adjustable, > then perhaps it should be disabled and a separate, > standalone, LV warning set for 13.0 volts be driven > from the MAIN bus. > > Finally, if push comes to shove, there's no sin in > leaving the e-bus alternate feed switch closed during > normal operations. The diode is there to prevent back- > feeding the main bus should you find it necessary to > revert to battery only operations. > > Sorry for the fire-drill. > > Bob . . . > > ________________________________ Message 9 _____________________________________ Time: 10:33:27 AM PST US Subject: AeroElectric-List: Re: Z16 voltage concern From: "user9253" > Is it possible to construct my own bridge using Schottkey diode's, or is that silly? The advantage of using a diode bridge with mounting hole in the center is its mechanical robustness. Two discrete diodes will function electrically just as well, as long as they are mounted securely for mechanical strength and heat dissipation. If it is desired to boost the voltage output from the Rotax regulator from 13.5 to 14, a Schottky diode could be put in series with the wire going to the regulator "C" terminal (arrow pointing towards the regulator). I have not actually done that but it should work. My Rotax voltage regulator puts out 13.6 volts. That might not be enough to top off a discharged battery, but the engine starts so quickly that it does not get run down much. I connect a battery maintainer when not flying. Everything works fine so I have not tried to boost the regulator voltage. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=356109#356109 ________________________________ Message 10 ____________________________________ Time: 10:34:56 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z16 voltage concern At 11:00 AM 10/27/2011, you wrote: > >Your right Bob, I just wanted see normal, or as close to normal, as >possible. It's a good dignastic tool. Is it possible to construct my >own bridge using Schottkey diode's, or is that silly? Not at all. I selected the single hole, potted 'brick' of plastic with 4 diodes for it's simplicity of mounting, no insulation needed, and fast-on tabs. In most applications we used only one of the four diodes . . . the other three were not 'in the way' of successful exploitation of other features for the device. If you only need one diode, then there's a host of offerings from the electronics suppliers. There are a number of dual Shottky devices that feature two diodes in the single package. Here's one example: http://tinyurl.com/4x87a6s This particular device does need to be insulated from its heat-sinking surface like so . . . http://www.aeroelectric.com/Catalog/AEC/9001 Bob . . . ________________________________ Message 11 ____________________________________ Time: 11:05:19 AM PST US From: Subject: Re: AeroElectric-List: Re: Z16 voltage concern Thanks! ---- user9253 wrote: ============ > Is it possible to construct my own bridge using Schottkey diode's, or is that silly? The advantage of using a diode bridge with mounting hole in the center is its mechanical robustness. Two discrete diodes will function electrically just as well, as long as they are mounted securely for mechanical strength and heat dissipation. If it is desired to boost the voltage output from the Rotax regulator from 13.5 to 14, a Schottky diode could be put in series with the wire going to the regulator "C" terminal (arrow pointing towards the regulator). I have not actually done that but it should work. My Rotax voltage regulator puts out 13.6 volts. That might not be enough to top off a discharged battery, but the engine starts so quickly that it does not get run down much. I connect a battery maintainer when not flying. Everything works fine so I have not tried to boost the regulator voltage. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=356109#356109 ________________________________ Message 12 ____________________________________ Time: 01:53:20 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: AeroLeds A few weeks ago there was some discussion on the List about noises from some AeroLed products. I cruised their website and promised to inquire into the marketing philosophy for their lighting products. I had some good conversation with one of the principals, a Mr. Nate Calvin. These guys are not the new kids on the block. They've delivered product to some very sophisticated customers who would demand careful scrutiny of mechanical and electrical characteristics. Nate tells me that all their product meets or exceeds DO-160 requirements for conducted noise in small aircraft. I'll remind readers that passing all the tests does not mean ZERO noise emissions . . . only that they are below the industry approved limits for this an all other electronics offered to the type certificated aircraft market. He recalled one case where an observed noise problem turned out to be a design problem with an intercom that was not fully vetted for living in the DO-160 world of light aircraft. Bottom line is that AeroLed products are very low risk for contributing to a noise issue. When they are identified as an observable noise source, the investigator should consider poor design of the victim system and/or some form of installation error first. Bob . . . ________________________________ Message 13 ____________________________________ Time: 01:53:21 PM PST US Subject: AeroElectric-List: Canopy Switch From: "user9253" A canopy-open indicator light does not help much to remind the pilot to latch the canopy. The pilot will become accustomed to seeing that light on while she taxies, trying to keep cool with the canopy open. What is needed is an audio and visual alarm that ONLY activates if the canopy is not latched for takeoff. I thought about using a microprocessor but am not proficient at programming. Then I found this LM2907 "RPM Speed Switch". Although it requires a few resistors and capacitors, all of the active components are contained in one 8-pin IC. Here is a proposed circuit: https://lh5.googleusercontent.com/-fI7pwRbufgI/Tqm5F18UY5I/AAAAAAAAAcw/QWs0GHx4q1I/s800/Canopy%252520Alarm.gif And here is the datasheet for the LM2907: http://www.national.com/ds/LM/LM2907.pdf Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=356119#356119 Attachments: http://forums.matronics.com//files/canopy_alarm_272.gif ________________________________ Message 14 ____________________________________ Time: 04:24:06 PM PST US Subject: AeroElectric-List: Audio Design From: "messydeer" Hi! I haven't yet bought any communication devices for my Sonex. I plan to get a COM radio, intercom, a couple headsets, and a couple PTT switches. I've got an MGL Enigma EFIS that can transmit audio warnings that I'd like to wire into the system. I'd also like to wire in an external audio device, like my cell phone which has an MP3 player and maybe an AM/FM radio or tablet computer. I think I'll pass on the DVD player. My goal is to get something that's dependable and affordable with an eye towards upgrading. Suggestions on what to get and how to wire these guys would be helpful. Thanks :-) -------- Dan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=356135#356135 ________________________________ Message 15 ____________________________________ Time: 04:47:45 PM PST US From: Michael Welch Subject: Re: AeroElectric-List: Audio Design Dan, I sure do like Icom products! An Icom IC210 would make a great com radio(or even an IC200). It's super easy to hard-wire an intercom to, which is what I did, or if I'm not mistaken, the IC210 may even have a built-in intercom (2 place). I needed the rubber "knob condoms" on my older IC200, (they dried out and cracked off) and when I told the parts guy what I needed he just sent them to me for FREE!!! They even paid for the shipping. I like Icom. Mike Welch > Suggestions on what to get and how to wire these guys would be helpful. > > Thanks :-) > > -------- > Dan ________________________________ Message 16 ____________________________________ Time: 04:52:31 PM PST US From: Michael Welch Subject: Re: AeroElectric-List: Audio Design Dan, Like this one: http://www.ebay.com/itm/Avionics-Icom-ICA210-IC-A210-VHF-Communication-Radio-/330614367526?pt=Motors_Aviation_Parts_Gear&vxp=mtr&hash=item4cfa26e526#ht_500wt_754 I see I messed up the model #. It was supposed to be IC "A"210. It's been many months since I was working with the radios. Mike ________________________________ Message 17 ____________________________________ Time: 04:57:51 PM PST US Subject: Re: AeroElectric-List: AeroLeds From: James Kilford Interesting stuff there Bob. On 27 October 2011 21:47, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > > A few weeks ago there was some discussion on the List about > noises from some AeroLed products. I cruised their website and > promised to inquire into the marketing philosophy for their > lighting products. > > I had some good conversation with one of the principals, > a Mr. Nate Calvin. These guys are not the new kids on the > block. They've delivered product to some very sophisticated > customers who would demand careful scrutiny of mechanical > and electrical characteristics. Nate tells me that all > their product meets or exceeds DO-160 requirements for > conducted noise in small aircraft. > > I'll remind readers that passing all the tests does not > mean ZERO noise emissions . . . only that they are below > the industry approved limits for this an all other electronics > offered to the type certificated aircraft market. > > He recalled one case where an observed noise problem > turned out to be a design problem with an intercom > that was not fully vetted for living in the DO-160 > world of light aircraft. > > Bottom line is that AeroLed products are very low > risk for contributing to a noise issue. When they > are identified as an observable noise source, the > investigator should consider poor design of the victim > system and/or some form of installation error first. > > > Bob . . . > > ________________________________ Message 18 ____________________________________ Time: 10:04:54 PM PST US Subject: AeroElectric-List: Re: Audio Design From: "messydeer" Thanks, Mike. I've heard ICOM makes quality stuff. But it's a bit big, both in price and size. I just realized MGL has an intercom in their V10 radio. They're also releasing soon their newer version, the V6. Reports say these intercoms actually work well, as opposed to earlier combo units of a different technology from other manufacturers. They'll be around $1000. If I go this route, it also simplifies things. Just connect the wires according to their diagrams. I got a little experience making a Dsub harness a few months ago, so I should be set. -------- Dan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=356155#356155 ------------------------------------------------------------------------------------- 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.