---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 03/16/12: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:12 AM - Re: USB (Christopher Cee Stone) 2. 06:48 AM - Poor Wiring Practice for VHF Noise? (stearman456) 3. 06:56 AM - Re: USB (Robert L. Nuckolls, III) 4. 08:02 AM - Re: USB (Christopher Cee Stone) 5. 11:19 AM - Re: Poor Wiring Practice for VHF Noise? (Robert L. Nuckolls, III) 6. 04:53 PM - white residue on solder (bob noffs) 7. 07:14 PM - Re: white residue on solder (Robert L. Nuckolls, III) 8. 11:04 PM - Re: white residue on solder (David Lloyd) ________________________________ Message 1 _____________________________________ Time: 06:12:03 AM PST US Subject: Re: AeroElectric-List: USB From: Christopher Cee Stone Bob... Thanks for the clarification... my point is simply that plugging a device into a USB jack may not provide the same level of charging as the device would receive from a dedicated wall wart charger. ...chris > USB charging. > > USB ports do not just provide 5v for the device under charge. The USB > port provides intelligent charging in so much as it poll s the device and > produces a charging current that is tailored to the battery state. In most > cases the default charge (no polling response) is trickle charge. This can > be as low as 20mA which will not run and charge some devices. > > . . . the operative word here is "SOME". It is > true that some devices are supplied with a dedicated > charger. > > The "wall charger" illustrated in the first link . . . > > [image: Emacs!] > > Is not a 'smart' charger. It's merely a 5V power supply > that includes a couple of bias networks intended to convice > the powered device that there is a 'real' USB client on > the other end of the cable . . . silent but real. > > Some power supplies do not include these resistors. My > Motorola mobile phone rejects some of the USB power > sources I've attempted to use but most 'foreign' chargers > work just fine with this particular phone. > > Without a doubt, any USB port on a computer used to > power up an external device is nothing more than a limited > current, 5V power supply with a couple of terminals for > bi-directional serial communications. USB devices intended > to work in concert with industry standard devices contain > identification data that is automatically offered to > your computer which will then search the list of presently > installed drivers that will provide a common language for > accomplishment of a task. This is why your computer automatically > recognizes many common tools like mice, keyboards, imaging > devices, etc. . . . while others don't wake up the computer > until a unique driver is installed. > > POWERING up a remote device, CHARGING that device's > battery and COMMUNICATING with that device are separate > and only slightly related tasks. I've designed several > USB interface devices where the +5V from the host computer > is not even hooked up. Current demands for my product > were too great to push off onto the computer. > > None of my projects included batteries . . . but if they > DID . . . and assuming I wanted to utilize an external > +5 volt source to CHARGE those batteries . . . all the > intelligence needed would be built into MY device. I'm > aware of no USB port on any PC that offers any measure of > control of the 5V supply line. In fact, given the huge > constellation of specialized battery charging protocols, > it would not make sense to integrate such features into > a PC. > > So you buy a battery powered device that comes with a > USB cord and perhaps a 'wall wart' for charging. All > bets for universal connection with other USB 'power > sources' is problematic. There are third party > chargers (like IGO) with specialized 'tips' > that not only brings +5 (or some other voltage) to the > portable device -AND- no doubt does some things to > spoof the portable into believing the foreign source > of power is 'friendly'. > > [image: Emacs!] > > I probed the 6 interface pins in this adapter (which > works with my mobile phone) and found THREE resistors. > No doubt they are necessary to effect a friendly > interconnection with the phone. There are only 3 wires > between the adapter and the power supply so at least > one and perhaps two of those resistors are used to > "talk to the power source" with the remainder used > to placate the mobile phone. > > Bottom line: > > There's an old adage that says "If it looks like > a duck, quacks like a duck and walks like a duck . . . > it must be a duck." > > The context of "USB" port discussions here on the List > is to provide a miniature version of the legacy cigar > lighter receptacle wherein power provided is not > ship's bus but a clean, regulated source of 5 volts. > These 'ducks' do indeed have common appearance and > they WALK like other ducks . . . but they don't TALK > like the others . . . and don't need to. > > One could consider adapting a compact, multi-port > device like this . . . > > [image: Emacs!] > > mounted on the panel and then wired to a 5V > DC-to-DC down converter . . . > > [image: Emacs!] > > Available for a few dollars . . . postage > paid. > > Some caveats: > > Given that this $3 device powers devices with much > greater $cost$ from a very robust energy source, it > might be prudent to craft some sort of OV protection > system. These are switchmode power supplies that > can either run un-regulated -OR- fail with a mode > that applies full bus voltage to your USB cord > connected precious. > > These are switchmode power supplies. They MIGHT > pose a risk to other devices on the panel . . . most > notably receivers. I've had several commercial-off- > the-shelf cigar lighter adapters that would tear up > AM radio reception under certain conditions. > > Should it happen that your particular device balks > for lack of characterization (like an IGO A32 tip) > then you might have to buy the tip designed to > 'talk' to your device and adapt or clone it into > your airborne, USB connector based POWER distribution > system. > > Bob . . . > ________________________________ Message 2 _____________________________________ Time: 06:48:43 AM PST US Subject: AeroElectric-List: Poor Wiring Practice for VHF Noise? From: "stearman456" Hi Bob, Would it be poor practice from an RFI point of view to run the avionics bus + wire and the strobe light power supply (Whelan A13A, HDA CF-14/28 ) + wire in the same bundle? Or the VHF + wire (remotely located Garmin SL40) and strobe light power supply + wire in another bundle? My switch panel is almost finished and will have these two bundles coming in and then going out of it. The "fat" wires are all up front on the firewall about 4 ft away. Dan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=368676#368676 ________________________________ Message 3 _____________________________________ Time: 06:56:46 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: USB At 08:05 AM 3/16/2012, you wrote: >Bob... > >Thanks for the clarification... my point is simply that plugging a >device into a USB jack may not provide the same level of charging as >the device would receive from a dedicated wall wart charger. Sure. It doesn't make much marketing sense to have a dedicated, 'smart' wall wart charger for any product. Smart chargers need to communicate with the client device . . . ostensibly over the native USB serial data lines. This connects the device and it's charger at the hip and locks out millions of opportunities for the device's owner to exploit other charging sources. That's sort of like selling a car that runs only on say kerosene. Even if kerosene were $1 gallon, there's no depth or breadth of supply that would make it an attractive transportation fuel. That's a recipe for marketing disaster. The constellation of on-board battery management chips targeted for inclusion within a battery or its companion device is huge. The art and science of application for such devices is well developed and pretty much standard procedure. To move battery management out into a companion charger and further complicate it's function with serial exchange of performance data seems somewhat self-defeating. But for the most part, it's a free-market decision that will ultimately be vetted by consumer product reviews and consumers credit cards that stay out of sight in their wallets. Bob . . . ________________________________ Message 4 _____________________________________ Time: 08:02:06 AM PST US Subject: Re: AeroElectric-List: USB From: Christopher Cee Stone > > USB charging cont. > > USB.org is in the process of crafting a specification that defines charging protocols for battery powered devices connected through USB. In as much as this will help to standardize the USB as charger it also provides for a common charger interface for these devices. As with all technology this one is changing rapidly... so while a 5v 500mA supply may work now, as devices evolve it may become a low performance default when connected to the latest techno whizzies. chris > http://www.usb.org/developers/devclass_docs > Sure. It doesn't make much marketing sense to... > > > Do not archive ________________________________ Message 5 _____________________________________ Time: 11:19:35 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Poor Wiring Practice for VHF Noise? At 08:45 AM 3/16/2012, you wrote: > >Hi Bob, > >Would it be poor practice from an RFI point of view to run the >avionics bus + wire and the strobe light power supply (Whelan A13A, >HDA CF-14/28 ) + wire in the same bundle? Or the VHF + wire >(remotely located Garmin SL40) and strobe light power supply + wire >in another bundle? My switch panel is almost finished and will have >these two bundles coming in and then going out of it. The "fat" >wires are all up front on the firewall about 4 ft away. In the heavy iron bird business, products bolted to airplanes are expected to be friendly citizens of the avionics community. In fact, there is a price of admission for gaining a seat aboard a type certificated aircraft. See: http://www.aeroelectric.com/articles/Philosophy/Whats_all_this_DO160_Stuff_Anyhow.pdf When every systems guy has to fight for and then jealously guard space on the airplane allotted to his efforts, it would be a disaster of some discovery were made where separation of certain wires from certain other wires was necessary or useful. Short answer is that wire bundles properly installed do not need to be separated for the purpose of protecting the performance of the home system or its neighbors. Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 6 _____________________________________ Time: 04:53:56 PM PST US Subject: AeroElectric-List: white residue on solder From: bob noffs hi all, i made a brass float for my fuel level indicator using solder. one area soldered has a white residue [maybe from resin] after being submerged in av gas 6 months. not all soldered areas have it. i could have easily used 2 different solders. i want to get into a small area on the float and make a repair. anyone know a solvent, liquid that would remove the chalky residue? it is a very thin layer and no threat to my fuel system but i want to get a clean area for a good bond. thanks, bob noffs ________________________________ Message 7 _____________________________________ Time: 07:14:51 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: white residue on solder At 06:52 PM 3/16/2012, you wrote: >hi all, > i made a brass float for my fuel level indicator using solder. one > area soldered has a white residue [maybe from resin] after being > submerged in av gas 6 months. not all soldered areas have it. i > could have easily used 2 different solders. i want to get into a > small area on the float and make a repair. anyone know a solvent, > liquid that would remove the chalky residue? it is a very thin > layer and no threat to my fuel system but i want to get a clean > area for a good bond. > thanks, bob noffs Without knowing more about the chemistry, its a toss up for being water soluble . . . or needs something else. You can't hurt the brass. Try water/solvent/acetone . . . or if push comes to shove, polish the brass with fine steel wool. Bob . . . ________________________________ Message 8 _____________________________________ Time: 11:04:44 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: white residue on solder ..use a little rubbing compound or similar and scrub with a toothbrush or similar. The brass has to brightened anyway to do a good solder touch up.... D ----- Original Message ----- From: bob noffs To: aeroelectric list Sent: Friday, March 16, 2012 4:52 PM Subject: AeroElectric-List: white residue on solder hi all, i made a brass float for my fuel level indicator using solder. one area soldered has a white residue [maybe from resin] after being submerged in av gas 6 months. not all soldered areas have it. i could have easily used 2 different solders. i want to get into a small area on the float and make a repair. anyone know a solvent, liquid that would remove the chalky residue? it is a very thin layer and no threat to my fuel system but i want to get a clean area for a good bond. thanks, bob noffs ------------------------------------------------------------------------------------- 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.