20 Jan
2011
20 Jan
'11
12:16 a.m.
On 2011 Jan 18, at 10:51 AM, Tony Duell wrote:
Narrows the problem down, but then you still don't know whether it's
the emitter or detector.
If the logic analyser gives indication of blocked beams as you stated
in your original message, why not just poke a finger around on the
screen to find which locations don't change the data stream (or change
it for only one axis). Appropriate poking sequences should distinguish
between X & Y blockages. (Assuming the detectors feed selectors giving
individual time slots in the data stream, as opposed to being
wire-ORed.) Or finger poking on the good beams to map out the data
stream.
Similarly, power up an IR LED and run it past the holes of the
detectors and look for activity/change on the detectors data line.
It may be less work in the end to make up some kind of tester to plug
into the touchscreen PCB and display the status of all the beams...