Wind Vane kit as it comes packaged from Fascinating Electronics
Anemometer kit as it comes packaged from Fascinating Electronics
The "T"-mount kit as it comes packaged from Fascinating Electronics. It's really more a "Y" - at the top of each fork you can mount either the anemometer or wind vane.
Completed T Mount (Y mount is more like it.) It's useful to do the PVC gluing over wax paper.
Completed Y Mount.
Measuring out the cable feed to the sensors. This is a CAT5, 8 conductor cable. The casing will get split back to the base of the T so that 4 conductors can go through one branch and two conductors to the other branch.
Split the CAT 5 shielding back to the base of the T that you measured in the previous photo. Expose the wires and group them into 4, 2 and 2. 4 will be used for the wind vane, 2 for the anemometer, and 2 will go unused (for now.)
Exposed wire, 4 for the wind vane, and 2 for the anemometer.
Using a 3rd hand, solder header pins to cable.
4 pin wind vane connector. The outer conductors are +5V and GND. The inner conductors are for variable voltage readings coming back from the dual wiper potentiometer in the wind vane. The voltage is proportional to the 180 degrees within which the wiper travels. However, on the outer bands of each wiper, one is usually "out" so it's a combination of the wipers that gives you the direction reading.
T-Mount with the Wind Vane 4 conductors fed through.
T mount with the anemometer conductors fed through.
Bottom of T mount showing how the conductors split - 4 to the left go to the wind vane, 2 to the right go to the anemometer. The blue conductors are not used (this was a CAT5 cable - 8 conductors.) I left the blue conductors wadded up inside the T-mount in case I might want to use them later for another purposes, say, temperature or humidity readings.
Wind vane tail fin mounting.
Interior cup of the wind vane. You can see the bearing embedded in the top of the cup. The outer cup free-wheels over the inner cup on the bolt axis.
Wind vane dual-wiper potentiometer.
Dual wiper with a home-made cable assembly that will connect with the conductors in the T-mount.
Pig tail soldered onto dual-wiper potentiometer. Do not orient the leads this way. They really need to be facing downwards. I resoldered them so they fed down after this photo was taken because the cable is too crimped inside the pipe where the dual-wiper is fixed.
This is one of the coolest parts of the design of the Fascinating Electronics wind vane. There's a semi-flexible piece of rubber tubing that slides over the shaft of the wind vane and connects to the potentiometer arm. Again, the pigtail cable should be pointing down instead of up as it is in this picture. This assembly slides down into the T-Mount pipe and the cable really needs to feed downwards so it doesn't crimp inside. The two holes in the metal bracket are used to fix the potentiometer inside the pipe by two set screws.
I'm testing the wind-vane assembly on the bench. Using my bench power supply, I injected +5V in and measured the voltage of the wiper outputs. The voltage of one wiper will recede while the voltage on the other wiper rises. After you pass the 180 degree point of the wipers, they flip. It's these voltage outputs that will be measured by the AVR MT 128 analog to digital converters. The AVR MT 128 will also supply the +5V to the wind vane potentiometer through the cable feeds.
Anemometer wind cup assembly.
Anemometer magnets. Each magnet is epoxied into the head of the anemometer cup. These will actuate a magnetic switch - on and off based on the polarity of the magnet. The AVR MT 128 will count the number of times the switch activates within a span of time in order to figure out the wind speed.
This shot is of an anemometer wind cup attached to the cap with the magnets.
This is part of the anemometer which contains the embedded magnetic switch and ball-bearing. This part will feed inside the part that contains the magnets and both will share the same bolt axis. A spacer is used to keep the top part of the moving wind cups from binding with the bottom. The wind cup assembly spins free over this switch.
Anemometer magnetic switch assembly interior.
Mag switch assembly with the spacer that lets the wind cup assembly freewheel over the switch.
Anemometer mag switch assembly. Notice the dab of epoxy to keep the plastic nut from working loose. Make sure that the switch height is adjusted correctly (top and bottom nuts on the black switch) by assembling the anemometer and gently turning it to see if it will free-wheel. Be careful because the mag switch is fragile - if it binds on the magnets you could damage it. After it free-wheels, put a continuity meter on the two wires and make sure that as it slowly spins you see an on-off continuity that will indicate the the switch is close enough to the magnets to activate it. Only after you've tuned and adjusted the anemometer should you epoxy the black nut in place on top and bottom.
Mag switch. Notice the dab of epoxy between the black plastic nut and the inside edge of the cap. This will keep the nut from working loose. The same caveat applies as the last photo - make sure you can assemble and free-wheel the anemometer head and get good magnetic switch transitions before you epoxy the nut in its final position.
Connecting the wind vane potentiometer to the conductors coming from the T-mount. I hot glued the exposed conductors partially to make sure they didn't touch if compressed in some way but also to try to hedge against moisture potentially getting trapped inside the pipe.
Completed wind sensors prior to external mounting. It's good to bench test it again in this state before mounting it on the exterior. Notice the set screw mid-way up the pipe on the left side wind vane. There's a hole directly below the screw which is the original hole. I could not easily get the potentiometer to seat that far down and had to finally punt and drill a new set screw hole and epoxy the original closed. I thought getting the potentiometer set in the pipe was the most difficult part of building the wind sensors.
Start of the cable breakout. I wanted to be able to easily dig into the signals on the cable. I use this little punch down jack, epoxied it to the perf-board to make it very secure. Then I took punch down wires to sockets on the perf board. This turned out to be very convenient to have during debugging the firmware and jacking into it with an oscilloscope.
AVR MT 128 wired up to the cable breakout perfboard. The yellow 10BaseT cable comes from the end of the wind sensor cable that I fed down through the roof vents. It's simply a pass-through of the 6 wires (4 wind vane, 2 anemometer) to the cable breakout.
Naked underside of the AVR where the cables will be connected.
DB9 standard serial interface and the white connector to the right of the DB9 will give you TTL serial access to the board.
Shows the AVR MT 128 underside connected to the cable breakout. This looks a lot messier and complicated than it really is. There's really just +5V and GND, 2 variable voltage wires coming from the wind vane and two for the anemometer. See the schematics section of the site for how these connect precisely.
Shows the AVR MT 128 underside connected to the cable breakout. This looks a lot messier and complicated than it really is. There's really just +5V and GND, 2 variable voltage wires coming from the wind vane and two for the anemometer. See the schematic for how these connect precisely.
Just the wires coming from the cable breakout.
Completed and mounted wind sensors. I mounted the sensors to an iron pipe stub. Then banded the stub to a metal pole mount that used to be used for an exterior 802.11 antenna. I used a metal stub so I had a very secure way to band the assembly. The metal pole was an odd diameter. I am sure you can make a much more attractive mount - this was purely functional and has held up well even in 60+ mph winds.
Completed and mounted wind sensors. I mounted the sensors to an iron pipe stub. Then banded the stub to a metal pole mount that used to be used for an exterior 802.11 antenna. I used a metal stub so I had a very secure way to band the assembly. The metal pole was an odd diameter. I am sure you can make a much more attractive mount - this was purely functional and has held up well even in 60+ mph winds.
Completed and mounted wind sensors. I mounted the sensors to an iron pipe stub. Then banded the stub to a metal pole mount that used to be used for an exterior 802.11 antenna. I used a metal stub so I had a very secure way to band the assembly. The metal pole was an odd diameter. I am sure you can make a much more attractive mount - this was purely functional and has held up well even in 60+ mph winds.
The one and only time the wind sensors stopped working was during a spring ice-storm we had in Colorado. They were free for a long time but eventually succumbed to the ice.