DIYbanter - View Single Post - Wind Speed Problem with Heathkit ID-4001

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I have a problem with my Heathkit ID-4001 Weather Station. The wind
speed works fine if there is any wind but when there is a calm wind
condition it occasionally starts giving erratic wind speeds. If it
should be reading zero speed, it reads zero and then jumps to a higher
wind speed, such as 32 and then back down to zero or up to 41. There
doesn't seem to be any pattern that I can discern. The actual wind
speed values tend to be random and when they occur appears to be random.

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I have an ID-4001 and I'm running into a similar problem. Mine, however
is with the direction giving random readings. In normal operation, say
the wind is from the southeast. All of a sudden, the indicator will
jump to northwest. It doesn't "turn" to the northwest, it will all of a
sudden "jump" there. I've tried to get it to do it by manually
rotating the wind vane, but just can't seem to re-create the problem.

I'm kind of thinking that the problem may be in the 8-wire cable. I'm
still using the original cable that came with the kit. Having wire
outside for that many years, maybe it's corroding and not allowing the
full 5 volts through.

Just a thought. Anyone care to comment?

Since it's not a constant problem, I haven't set aside time to check
voltages.

It might very well be the wire but in my experience the problem with
erroneous wind direction indications has always been the failure of one
the photosensors or LEDs due to a static discharge or a nearby lightning
strike. The LEDs are wired in series so that if one goes they all do
not work and wind speed goes to zero and the wind consistently indicates
only one direction which I believe is SE. This does not appear to be
the case for you so I would suspect one of the photosensors - or a bad
wire as you suggest. The wind direction indication is the only
function that does not go through the CPU so you can rule that out as a
possible problem.

Before replacing the wire, I might have someone slowly spin the
weathervane around full circle several times while you note exactly
which of the direction indicator LEDs light and in what order. I would
then examine the Gray code listing in table 5-3 on page 21 of the
Operations manual and see if you can see a pattern that would point to a
particular failed photosensor. If not a photosensor it might also point
to which of the wires is the problem.

Good luck.