Reprogramming the AAG RS485 Weather Station

robtillaart:
Is it possible to read the strength of the hall sensors? (now I see only 0/1)

If so these could be used to interpolate between the values. The 16 wind directions are steps of 360/16 = 22.5, if interpolation is possible you may could get to 5 degrees accuracy

Not likely. Hall effect sensors come in two varieties, those with a digital output and those with a analog output. Sounds like this weather station is using simple digital output hall sensors.

Lefty

Is it possible to read the strength of the hall sensors? (now I see only 0/1)

They are Allegro 3144 which is now obsolete and replaced by the A1104. Unfortunately, like Lefty points out, they are digital devices, so no interpolation will be possible. Just from watching the wind vane while I had it up on a pole, the direction oscillated quite a bit. I don't know that wind direction is stable enough to warrant 5 degree resolution. Not Texas wind anyway. :slight_smile: We have a saying here, if you don't like the weather just wait 5 minutes.

That's an interesting idea though. If I ever decide to replace the circuit board, I could try linear Hall sensors.

EmilyJane:
I had a chance to play with the weather station and wrote this code to set up the ports and get wind direction.

Nice!

A suggestion and an idea. Suggestion...

const char* windDirection[17] = { // strings for the 16 wind directions
"N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW",
"SW", "WSW", "W", "WNW", "NW", "NNW", "---"};

...very slightly simplifies displaying the wind...

uint8_t d = make_wind(); // Sophomore humor. Got to love it. Hmm, I think I'll watch Shaun the Sheep tonight...
d = match_wind(WD, d);
Serial.println(windDirection[d]);

Idea... interpolating (guessing) the wind direction... By tracking the wind direction versus time, it is possible for the application to provide a guess at the exact wind direction.

I just finished modifying the board to include a 4K7 pull-up on the 1-wire pin. The DS1850 that I removed is obsolete too. The Chinese must have a stockpile of old parts. Or maybe they buy them up as they go obsolete.

I don't know if I'll put a temp sensor back inside the enclosure or not. It's useless for weather applications.

I removed 4 (of the 35!) LEDs just to give myself a little room to work. I may remove all of them. That will free up 6 I/O pins. Maybe I'll leave a couple as a warning to low flying birds or squirrels. :slight_smile:

...very slightly simplifies displaying the wind...

So, if i don't get a match, I display "---"? That's a good idea. I think it's physically impossible to not have one of those patterns though. That would signal a problem with the circuit.

Idea... interpolating (guessing) the wind direction... By tracking the wind direction versus time, it is possible for the application to provide a guess at the exact wind direction.

That's an interesting idea. That would be helpful for displaying trends also. I'll work on that. I'll probably average wind speed over some period also.

Sophomore humor. Got to love it. Hmm, I think I'll watch Shaun the Sheep tonight...

Sometimes you get tired of meaningful function names and have to go with a little smile. :slight_smile: Makes life a treat!

We have a saying here, if you don't like the weather just wait 5 minutes.

Bah! I grew up in the place that has the World's Record for the fastest temperature change. Texas weather is slow and stable by comparison. :smiley:

Sounds like Gunnison. I used to have a house in Crested Butte and one day in Almont they measured -60! You had to keep your car battery indoors.

Quote
Idea... interpolating (guessing) the wind direction... By tracking the wind direction versus time, it is possible for the application to provide a guess at the exact wind direction.

That's an interesting idea. That would be helpful for displaying trends also. I'll work on that. I'll probably average wind speed over some period also.

Point of attention is if it alternates around 360 / 0 degrees,
The way I wouold approach it is count the number of times every individual sensor is triggered. There are 8 sensor so 8 counters, e.g. B00111111 means count[7]++ and count[6]++ . After a number of measurements a nice frequency diagram will come up from which the average can be derived.

I was stationed in Montana for the Air Force in the 60s where it would get down to -30F for a week at a time. We too had to keep our car batteries inside our barracks if we wanted to start our cars after work, All except one VW bug, it seemed to start no matter how cold.

Lefty

Seems to me that the wind direction will be somewhat obscured by the mass of the wind follower, that is sure to overshoot and oscillate to some degree. So not sure other then some 'averaging' code one could count of wind direction being anything but just a relative measurement. Same might be the case for windspeed impulses.

Lefty

Gotta love the bugs. My '59 was indestructible.

retrolefty:
Seems to me that the wind direction will be somewhat obscured by the mass of the wind follower, that is sure to overshoot and oscillate to some degree. So not sure other then some 'averaging' code one could count of wind direction being anything but just a relative measurement. Same might be the case for windspeed impulses.

Lefty

The wind vane does have significant momentum. That may account for the way it dances around in a gusty wind. I'm going to have an Arduino down on the ground managing it and the other sensors. I can keep a data base and play with the numbers a bit.

Some project pics.

All except one VW bug, it seemed to start no matter how cold.

Probably because the battery is underneath the back seat. Which is all sorts of fun when the bug rolls over.

There was a piece of plywood under mine to keep it from falling through the rusty floor pan. :slight_smile:

I hadn't been following this thread so I am catching up.

I used to have a house in Crested Butte ...

Then you might recognize my user name. Were you in C.B. when Larry T. was the doctor there?

I was stationed in Montana for the Air Force in the 60s where it would get down to -30F for a week at a time.

Were you at Glasgow AFB by any chance?

Don

Were you at Glasgow AFB by any chance?

No, Malstrom AFB in Great Falls, a SAC Minute Man missile base.

Lefty

Then you might recognize my user name. Were you in C.B. when Larry T. was the doctor there?

That is the first thing that came to my mind when I saw your user name. A run off the East River chair or if you're coming off the North Face. I remember the lonnnnng lines at that chair near the end of the day. And the VW size moguls on Resurrection.

I remember a "happy" doctor I believe by that name. Is that the one?

I didn't get the name from the ski run but from the same town (aka Ruby and Ruby-Anthracite) that the run was undoubtedly named for. Larry was the doctor for the ski area but I only visited him a few times, and that was in the summer, which as I recall lasted about two weeks. All he had to deal with then was dog bites and fish hook injuries. How many people do you know that have driven from Marble to Gothic via Schofield pass?

Don

I know the area. I have hiked the West Elk Wilderness area not too far from there.
I think you're talking about the doctor in the clinic on the mountain. I saw him for an injury or two. Yeah, summer was that period between the end of mud season and winter.

How many people do you know that have driven from Marble to Gothic via Schofield pass?

Not many. The "roads" are just jeep trails up there.