To connect my Peet Bros Anemometer to the Weatherduino, I will use an Arduino Nano as convertor.
When ready and working is confirmed, it will be available of-course for others so this great anemometer/dir combo can be added to the supported device list of the Weatherduino system.
I'm ready with the basics so what I have now is this:
What do I need to change to make the convertor board output Davis 6410 compatibel?
- windspeed output in m/s?
- wind direction- 0-360 degrees to ...?
Thanks!
PB Info:
The ULTIMETER PRO Anemometer is a patented, all-digital design for measuring both the
speed and direction of wind. The anemometer houses two magnetically-actuated reed
switches. Both open and close once each revolution of the anemometer assembly. We call the
lower reed switch, "the speed reed," and the upper reed switch, "the direction reed." The wind
speed measurement is derived from the speed reed, and the wind direction measurement is
derived from the speed reed and direction reed (both signals must be present).
In ULTIMETER Weather Stations, speed is determined by measuring the time interval between
two successive closures of the speed reed. Calibration is done as follows (RPS = revolutions
per second):
0.010 < RPS < 3.229 (approximately 0.2 < MPH < 8.2):
MPH = -0.1095(RPS 2 ) + 2.9318(RPS) – 0.1412
3.230 < RPS < 54.362 (approximately 8.2 < MPH < 136.0):
MPH = 0.0052(RPS 2 ) + 2.1980(RPS) + 1.1091
54.363 < RPS < 66.332 (approximately 136.0 < MPH < 181.5):
MPH = 0.1104(RPS 2 ) – 9.5685(RPS) + 329.87
Conversions used are: mph * 0.86897 = knots; mph * 1.6094 = kmph; mph * 0.48037 = m/s
Direction is calculated as the relative timing (phase relationship) between contact closures of the
two reed switches. This is a non-linear, sinusoidal relationship. We regard repeated actuation
of the speed reed as the reference and arbitrarily define "North" as the vane orientation that
causes the two reed switches to close at the same time. "South" is the vane orientation that
causes the direction reed to close exactly halfway between two closures of the speed reed.
We include several data checks in our systems:
We require that there be one and only one contact closure from one reed switch between
two successive closures of the other reed switch. This involves some special treatment
when the closures are nearly coincident.
At speeds above 10 mph, we measure speed twice, through two successive revolutions
of the anemometer. The two readings must agree within preset limits that vary with
speed.
We likewise measure direction twice, through two successive revolutions of the
anemometer. If the two readings do not agree within preset limits that vary with speed,
we do not display the new direction reading in the output. This is done to emphasize the
predominant wind direction and minimize excessive display fluctuation, without sacrificing
responsiveness.
When ready and working is confirmed, it will be available of-course for others so this great anemometer/dir combo can be added to the supported device list of the Weatherduino system.
I'm ready with the basics so what I have now is this:
- wind speed output is in MPH
- -wind direction is in degrees 0-360
- debounce checks
- the by Peter Bros (PB) recommended calibration formulas are incorporated
What do I need to change to make the convertor board output Davis 6410 compatibel?
- windspeed output in m/s?
- wind direction- 0-360 degrees to ...?
Thanks!
PB Info:
The ULTIMETER PRO Anemometer is a patented, all-digital design for measuring both the
speed and direction of wind. The anemometer houses two magnetically-actuated reed
switches. Both open and close once each revolution of the anemometer assembly. We call the
lower reed switch, "the speed reed," and the upper reed switch, "the direction reed." The wind
speed measurement is derived from the speed reed, and the wind direction measurement is
derived from the speed reed and direction reed (both signals must be present).
In ULTIMETER Weather Stations, speed is determined by measuring the time interval between
two successive closures of the speed reed. Calibration is done as follows (RPS = revolutions
per second):
0.010 < RPS < 3.229 (approximately 0.2 < MPH < 8.2):
MPH = -0.1095(RPS 2 ) + 2.9318(RPS) – 0.1412
3.230 < RPS < 54.362 (approximately 8.2 < MPH < 136.0):
MPH = 0.0052(RPS 2 ) + 2.1980(RPS) + 1.1091
54.363 < RPS < 66.332 (approximately 136.0 < MPH < 181.5):
MPH = 0.1104(RPS 2 ) – 9.5685(RPS) + 329.87
Conversions used are: mph * 0.86897 = knots; mph * 1.6094 = kmph; mph * 0.48037 = m/s
Direction is calculated as the relative timing (phase relationship) between contact closures of the
two reed switches. This is a non-linear, sinusoidal relationship. We regard repeated actuation
of the speed reed as the reference and arbitrarily define "North" as the vane orientation that
causes the two reed switches to close at the same time. "South" is the vane orientation that
causes the direction reed to close exactly halfway between two closures of the speed reed.
We include several data checks in our systems:
We require that there be one and only one contact closure from one reed switch between
two successive closures of the other reed switch. This involves some special treatment
when the closures are nearly coincident.
At speeds above 10 mph, we measure speed twice, through two successive revolutions
of the anemometer. The two readings must agree within preset limits that vary with
speed.
We likewise measure direction twice, through two successive revolutions of the
anemometer. If the two readings do not agree within preset limits that vary with speed,
we do not display the new direction reading in the output. This is done to emphasize the
predominant wind direction and minimize excessive display fluctuation, without sacrificing
responsiveness.