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* Open power connector for [[mobile phone]]s, [[PDA]]s and laptops. ''(Wikipedia lists [http://en.wikipedia.org/wiki/DC_plug a variety of connectors] -- or were you looking for an AC [http://en.wikipedia.org/wiki/Power_connector power connector]? What sort of specification do you want?)''
 
* Open power connector for [[mobile phone]]s, [[PDA]]s and laptops. ''(Wikipedia lists [http://en.wikipedia.org/wiki/DC_plug a variety of connectors] -- or were you looking for an AC [http://en.wikipedia.org/wiki/Power_connector power connector]? What sort of specification do you want?)''
 
*  "Open Source Disability Gadgets: DIY for PWD" [http://panelpicker.sxsw.com/ideas/view/1745] "Gear and software for people with disabilities is usually provided through charity or from medical supply companies. It's hard or impossible to repair it, or get anyone to repair it. We need to hack the model for accessibility tools! With a culture of open source designs, Instructables, wikis, and blogs, we can start an international movement."
 
*  "Open Source Disability Gadgets: DIY for PWD" [http://panelpicker.sxsw.com/ideas/view/1745] "Gear and software for people with disabilities is usually provided through charity or from medical supply companies. It's hard or impossible to repair it, or get anyone to repair it. We need to hack the model for accessibility tools! With a culture of open source designs, Instructables, wikis, and blogs, we can start an international movement."
* Maybe we should have a page on "bus termination". The "1/10 speed of light" rule of thumb; theoretical optimum "impedance matching" parallel end termination resistor; the advantages of (series) source termination over end termination (lower power, less EMI); Schottky diode termination clamps (lower power; protects against ESD). Also other things people put at the end of long cables -- stuff to deal with accidental electrostatic discharge (ESD); various ways to bias differential pairs so that "cable unplugged" doesn't cause lots of unwanted noise glitches; various ways of connecting the shield of shielded cables at one end or the other end or both; galvanic isolation -- MIDI-like opto-isolation; Ethernet-like transformer isolation -- etc. Perhaps a brief summary of the best answers from [http://electronics.stackexchange.com/questions/tagged/termination questions tagged "termination"] and [http://electronics.stackexchange.com/questions/tagged/signal-integrity questions tagged "signal-integrity"] would be good?
 
  
 
== open design laptop ==
 
== open design laptop ==
: ''main: [[PC#open laptop]]''
 
  
 
* Open design laptop (you can replace the components). ''(see [http://communitywiki.org/odd/ComputerComponent/CustomNotebook computer component wiki: custom notebook])''
 
* Open design laptop (you can replace the components). ''(see [http://communitywiki.org/odd/ComputerComponent/CustomNotebook computer component wiki: custom notebook])''
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* Many ham radio operators make all their equipment run on 12 V and a red/black Anderson Powerpole connector. [http://en.wikipedia.org/wiki/DC_connector#Anderson_Powerpole_connectors Wikipedia: DC connector#Anderson Powerpole connectors]
 
* Many ham radio operators make all their equipment run on 12 V and a red/black Anderson Powerpole connector. [http://en.wikipedia.org/wiki/DC_connector#Anderson_Powerpole_connectors Wikipedia: DC connector#Anderson Powerpole connectors]
* [[Barrel Power Jack]].
 
 
* Dale Davis makes all his equipment run off 12 V, and uses a standard cable everywhere with identical barrel power plugs -- center positive, barrel ground -- at both ends. [[Barrel Power Jack]]. The outer barrel is ground so that if a one end of the cord is plugged into 12 V power supply and the other end touches a metal case (which is always grounded), it's harmless. A nice feature of barrel plugs is that you can plug them in at any angle, and it Just Works.
 
* Dale Davis makes all his equipment run off 12 V, and uses a standard cable everywhere with identical barrel power plugs -- center positive, barrel ground -- at both ends. [[Barrel Power Jack]]. The outer barrel is ground so that if a one end of the cord is plugged into 12 V power supply and the other end touches a metal case (which is always grounded), it's harmless. A nice feature of barrel plugs is that you can plug them in at any angle, and it Just Works.
** [https://www.youtube.com/watch?v=eIJDOeSTQgM "Hacking a Dymo Letratag to run on a normal 12v adapter"]. ZL3CLV prefers barrel jacks center-positive, barrel-negative 12 V power, and re-wires things to make them conform.
 
 
* The [http://greenplug.us/ Green Plug] universal power adapter
 
* The [http://greenplug.us/ Green Plug] universal power adapter
 
* [http://www.myaups.org/ The Alliance for Universal Power Supplies]
 
* [http://www.myaups.org/ The Alliance for Universal Power Supplies]
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points out some non-obvious features that are nice to have in a power connector,
 
points out some non-obvious features that are nice to have in a power connector,
 
and makes some recommendations on which to use and which to avoid.
 
and makes some recommendations on which to use and which to avoid.
 
* https://douglasadams.com/dna/980707-03-a.html "Dongly Things"] by Douglas Adams: "Time to declare war, I think, on little dongly things. ... a possible DC power standard. ... we should probably just be grateful that it was designed by a car mechanic in an afternoon and not a computer industry standards committee ... Keep the voltage level, design a new, small, plug and you have a new standard. ...". Published MacWorld magazine; September 1996 (p. 140).
 
  
 
Is it possible for the device to "negotiate" for exactly the voltage it needs, such that the same power adapter provides different voltages to different devices?
 
Is it possible for the device to "negotiate" for exactly the voltage it needs, such that the same power adapter provides different voltages to different devices?
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* Perhaps the device could include a resistor+resistor voltage divider or resistor+zener voltage divider to produce a feedback voltage precisely 1.25 V lower than the voltage it desires, so a LM317 or equivalent regulator will produce exactly the desire voltage?
 
* Perhaps the device could include a resistor+resistor voltage divider or resistor+zener voltage divider to produce a feedback voltage precisely 1.25 V lower than the voltage it desires, so a LM317 or equivalent regulator will produce exactly the desire voltage?
 
* ... in such a way that the power adapter automatically produces 0 V or "disconnected" soon after any device is unplugged. (hmm.. that would not be the case using the LM317...)
 
* ... in such a way that the power adapter automatically produces 0 V or "disconnected" soon after any device is unplugged. (hmm.. that would not be the case using the LM317...)
* What do we need to do, ahead of time, to design things so they don't overheat, posing a safety risk? (Rather than, say, finding out problems after they are in the field, and issuing a recall).<ref>
 
[http://www.bbc.com/news/technology-28956813 "HP recalls more than six million power cords"]
 
</ref>
 
 
* ... ?
 
* ... ?
 +
  
 
== micro controller based voip client ==
 
== micro controller based voip client ==

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