Thread: Creative Misuse of Digital IO
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Unread 30-05-2005, 12:56
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Mike Betts Mike Betts is offline
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Re: Creative Misuse of Digital IO
Quote:
Originally Posted by Joe Johnson
This should be fine...
Dr. J.,

I would disagree. The TTL port is meant to be used by a device which derives it's power from the RC (such as a SMiRF or CMU2cam).

I am unsure if the RC has an optocoupler on this port. I rather doubt it. and you don't want the power supplies of the RC's fighting each other...

Unless IFI says different, I would wirewrap a small optical interface board where the RX side of each channel was powered by the receiving RC's +5V and GND. There are many optoisolators which can be used. As an example, I would recommend the HCPL2300 IC chip with a 3.3K series input resistor and a output inverter/buffer for this task.

If IFI says it is OK, you could connect only TX RX and GND and not connect the +5 power between RC controllers.

Bottom line, I would not direct connect without talking to IFI first.

Mike
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Mike Betts

Alumnus, Team 3518, Panthrobots, 2011
Alumnus, Team 177, Bobcat Robotics, 1995 - 2010
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LRI, WPI Regional, 2009 - 2010
RI, South Florida Regional, 2012 - 2013

As easy as 355/113...