You will need a pullup resistor of 10K or so on each input (all six)
as well as a current limiting resistor of 1K or so (another six).
Now in software you will need to initially make ALL six I/O pins
inputs.
From here you make only one I/O pin an OUTPUT and LOW at a time. Read
the remaining I/O pins to ensure that only ONE will produce a LOW,
otherwise
there is a SHORT indicated in the cable between conductors, ...or
if none of
the I/O pins read LOW then there is an OPEN indicated in the
cable. Restore
all pins to an INPUT state and proceed to the next I/O pin.
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>how can I use a BS to build a Harness cable tester
>
>Thank you,
>
>Edson
Edison,
Depends on how many conductors you are testing in the cable....
Suppose you had only 3 conductors, one approach would be to use
six stamp pins.
Example Circuit: (x3)
10K 10K
o--/\/\
>+5V<
/\/\--o
| 1K 1K |
I/O >--o--/\/\----/conductor/----/\/\--o--< I/O
You will need a pullup resistor of 10K or so on each input (all six)
as well as a current limiting resistor of 1K or so (another six).
Now in software you will need to initially make ALL six I/O pins
inputs.
From here you make only one I/O pin an OUTPUT and LOW at a time. Read
the remaining I/O pins to ensure that only ONE will produce a LOW,
otherwise
there is a SHORT indicated in the cable between conductors, ...or
if none of
the I/O pins read LOW then there is an OPEN indicated in the
cable. Restore
all pins to an INPUT state and proceed to the next I/O pin.
-Beau Schwabe