#1827 NORM CTest: Increasing voltage range of Analog Input

[Zarro Boogs per Child]

#1827: Increasing voltage range of Analog Input
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 Reporter:  arjs                           |       Owner:  wad  
     Type:  enhancement                    |      Status:  new  
 Priority:  normal                         |   Milestone:  CTest
Component:  hardware                       |     Version:       
 Keywords:  Analog, Sensor, Voltage range  |    Verified:  0    
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 The XO features the ability to measure and sample DC Analog Voltage.
 However the range of analog input that can be applied is restricted to
 0.41V - 1.96V
 (Ticket #42 )

 * Not being able to measure 0V/below 0.3V is a restriction.
 also,
 * It would be useful to increase the upper range to at least 3.3V or 5V so
 that then it would also be able to read digital input.


 Some applications of having such range would be - interfacing external
 circuits, interfacing external robotics modules (for example distance
 ranger) etc.


 Also, with a sensor connected, for example a MIC or a photo-voltaic cell,
 a larger voltage range would give the ability to sample voltage over a
 larger range. This would be useful in the light of the fact that some
 sensory input is also planned to be incorporated into TamTam or other
 activities.


 The add-on circuit could be in series to the microphone input, and could
 be made to bypass by using an electronic switch (for example SN74LVC1G66)
 and the control of the switch can be coupled to some of the controls of
 Alsamixer etc.

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Ticket URL: <http://dev.laptop.org/ticket/1827>
One Laptop Per Child <http://laptop.org/>