I want to measure wind direction in degrees and need a minimum resolution of 360°. Because of several reasons I want to use a mechanical solution. I guess the correct word for the thing I want to build is a wind direction vane.
Obviously for this I need a sensor which returns me the difference to a certain 0-position. I'd love to find a part which is physically big enough so I'm able to mount the vane directly onto it. Secondly, it would be great if I could read the sensor data easily via analog input on my arduino.
Since I'm relatively new to sensors I have no idea which is the right one? It must not have steps/clicks, no end/starting point and it should be turnable easily. And, as soon as I know how this thing is called, I have no idea how i find the specific type which fits the arduino.
I would love if you could help me with finding the correct sensor
A compass sensor mounted on your weather vane would give the dead direction, for example this one http://www.sparkfun.com/products/7915. There's the challenge of talking to it without tangling wires (unless the Arduino is also mounted on your vane?) Perhaps a wireless bee or similar might assist.
The rotary encoder seems to be the thing I was looking for, but they're pretty expensive!?
The compass idea is great, since it would make adjusting the vane to north unnecessary. But i dont want to mount the arduino on the vane, and I think using XBees will be a bit too much for what i thought will be a cheap project
Or, if accuracy is not that much of a problem, you could have a circle of slotted optical sensors and have the vane protrude at the bottom to break the beams as it rotates.
Or, if you only need it during daylight, have it obscure a circle of phototransistors.
I'd not seen one of these before, but Adafruit posted a youtube video for a product that is very appropriate for your project :
Means you could run the Sparkfun compass module (only requires 4 of the 6 available wires, so you could add more on top too !). I didn't research any other options but I'm sure there's heaps of compass modules out there to do the job.
I'm sure Adafruit are not the first to provide a product to do this...but it's the first I've seen since your post made me start thinking of how to beat the tangled wire challenge 8)
maybye a longshot but a continuosly rotating servo could be set to periodical float free, and the some time return to 0 (some arbitrary direction) the time it takes for the servo to return to zero is the equivalent of direction.
servo must be stronger than wind
wind speed would also have to be measured, and accounted for etc.
but servos return values of positions so i do belive it is possible, and could be very cheap(cost of 1 servo)
i dont know a ton about them. just probeing and sticking ideas out there.
thebfs:
maybye a longshot but a continuosly rotating servo could be set to periodical float free, and the some time return to 0 (some arbitrary direction) the time it takes for the servo to return to zero is the equivalent of direction.
servo must be stronger than wind
wind speed would also have to be measured, and accounted for etc.
but servos return values of positions so i do belive it is possible, and could be very cheap(cost of 1 servo)
i dont know a ton about them. just probeing and sticking ideas out there.
glad to see people think like me and have already done the work!
i think that would be you cheapest way to go and accurate enough you wont need the servo motor just the pot, and u may need to furthur mod the servo
Lookup continuous rotation servo for examples of the mod (their all over)
goodluck
