[Gumstix-users] Re: Last call re: robostix

[Sean L. <se...@cs...>]

If I'm understanding correctly from the discussion, it sounds like 
there are three pins for each digital in/out and analog in: power, 
ground, and signal return.  And that the power is presently tied to the 
raw unregulated power coming into the board (V_BATT?).  If this is 
correct (and I could be misunderstanding), it should *definitely* be 
changed. A very high percentage of robotics applications for which this 
board will be used will be running off of batteries whose voltage 
fluctuates with draw.  Sensors of various types absolutely need to have 
regulated power and don't have their own regulators.  Make sure they're 
getting regulated power through the power pin, and for the same reason 
I'd strongly suggest a bigger regulator: 700ma may not be sufficient 
for a large load of sophisticated sensors.  >= 1A is desirable.

As to higher voltage than 6V:  we're presently driving the acroname 
Brainstems we're using off of 6V 5-cell A or Sub-C packs, with servo 
power and power to the board tied to the same source (you should 
provide a jumper or solder jump to do this also).  This is because 
servos cannot run off of more than 6V or they risk damage.  So having 
the board run on 6V seems to be a reasonable value.

Craig, if you could hold off for a bit I will forward stuff to the 
hackers in my class and have them post responses and suggestions.

Sean