Since I've had my Oregon Scientific WMR928 weather station I have had the odd issue with the wind speed freezing during cold weather, (frost and snow). A couple of days ago I came up with an idea for a heater and did some experimenting with a spare anemometer and came up with this idea. It uses 2 wire-ended filament type 12V, 0 08A, 0 96W bulbs, the thinnest wire that will handle the bulbs and a Kemo Temperature Thermostat switch. This setup can run off a 12v battery or a 12v mains PSU. It delivers just the right amount of heat to eliminate any ice and snow build up. You can set the Kemo switch to cut in at what ever temperature suits you, I will have it set at around 2oC once it warms over this temperature then it will turn off the bulbs... Here's how I did it....
Items Needed:
Total cost should be no more than £30 |
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You need to loosen the tightening screws and remove the direction and the speed units as show in the 1st image below, leaving the housing as shown in the 2nd image, Then you need to remove the nut and washer as shown in image 3 below, then remove the screw that is holding the whole housing to the mounting pole and gently pull the housing off the pole, as shown in image 4 below... |
Now look in the hole where the pole used to be and you will see a press in clip, See 1st image below, using a screwdriver, push in the clip and push up and the same time so that you are releasing the inner sleeve, gently pull out the inner sleeve and the direction sensor will come out too, you can then gently pull out the small PCB that has the reed switch on it, NOTE: Be careful when pulling it out as the reed switch and wires are a little delicate. Now its all stripped down and ready for the wire with the bulbs attached. You really need to attach the bulbs to the wire as shown in image 3 below, the reason for this is so that you can have one bulb at the very bottom of the housing and one behind the small PCB. At this point you can insulate the back of the PCB where the bulb will go and the wires for the direction sensor as shown in image 2. |
It will be easier to route the wires by removing the screw that's in image 1 below and gently pulling the pipe out, Now you need the thread the wire into the housing and out through the SAME hole the flat 6 care cable is through, then through the pipe, pull it all through so your left with just the bulbs as shown in the 2nd image below (used thicker wire to show you), Now carefully refit the PCB holder holding the wires out of the way, make sure it goes all the way to the bottom else the other sleeve will not click into place. Now carefully push one bulb OVER the PCB and down to the bottom of the housing to the metal plate that holds the speed sensor bearing, then push the other bulb behind the PCB and pulling any spare cable through the hole so there is NO spare cable inside the housing at all. see image 3, you can see the bulb behind the PCB but the 1st bulb is now hidden. |
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IMPORTANT NOTES:
When wiring up the
switch (its normally open) you have to wire it up so its now normally
closed, the reason for this is because in normal use the switch is used
for setting off the relay once it reaches ahigher temperature,
but we want it to activate once it reaches around 2oC (lower
temp) so you must wire it so its normally closed, now the odd part. When
used in the normally open way, the switch activates the relay and the
LED on the switch comes on to let you know its switched, well because of
the need to wire it normally closed, the LED is permanently on until it
switches then it
turns off, i think it was an oversight at the manufacturing stage but it
took me around a day to figure out it still works as needed using the
fridge!
This is the completed power source switching unit, input is from a 12v battery housed in a waterproof container
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