Arduino and 1-wire based home built weather station.

[Gina]

I've decided to start a new thread for this though it follows on from two (or maybe three) others. My previous posts on my 1-wire weather station contain a lot of developmental material which can simply be skipped to go straight to my present situation.

I'll post details later but for now I'll just say that the present state of the 1-wire weather station build is that I have anemometer, wind vane and light level sensors built and working (well they were before some storm damage). I'm "borrowing" a F.O. rain gauge until I make my own. Yet to be added are humidity and atmospheric pressure. I did in fact buy a 1-wire humidity sensor kit but won't be using it as it requires calibration. OTOH the DHT22 Arduino humidity and temperature sensor is already calibrated and provides a digital output. I'm already using one of these very successfully in my astro DSLR cooling control (also Arduino based). There is also an atmospheric pressure sensor for the Arduino which I shall be getting.

A big plus for the Arduino is that it directly supports 1-wire so all my 1-wire stuff will connect directly without modification.

I'll post a block diagram of this latest weather station shortly.

[Gina]

Here's the block diagram :-

1-wire_weather_arduino_02.png

Oh dear, it hasn't come out very well

[Gina]

Here's the 1-wire circuit for the wind instruments. The vane direction is read using 4 LEDs and 4 photo-transistors with a Gray encoded plastic disc between (a duff CD with some of the coating scraped off, in fact). This resolves the 360 degrees into 16 directions - compass points.

[Gina]

This shows how I used three tracks on the encoding disc to provide 4 data bits.



And this diagram shows the construction details of the anemometer (made from half ping pong balls and bottle tops) and the magnetically damped wind vane and sensor. A rare earth super-magnet and an aluminium saucepan lid provide damping to stop the wind vane from waggling about and gives a smoother and more accurate wind direction.

[mermaidbeachweather]

This shows how I used three tracks on the encoding disc to provide 4 data bits.



And this diagram shows the construction details of the anemometer (made from half ping pong balls and bottle tops) and the magnetically damped wind vane and sensor. A rare earth super-magnet and an aluminium saucepan lid provide damping to stop the wind vane from waggling about and gives a smoother and more accurate wind direction.

Totally unbelievable, you have certainly gone to a lot of trouble and precision.
Good luck in the future.

Cheers

Brian

[steve]

This is brilliant. I particularly like that first there's all this technical and electronics stuff that goes right over my head, and then we get ping pong balls, bottle caps and saucepan lids

[Matt.j5b]

That is amazing, which is things I don't have a clue about. Hopefully it may work well for you in the future.

[Gina]

Thank you for your replies folks

I've had the "up the pole" sensors working well with 1-wire software written in Python under Linux (Mint flavour ) with local display but didn't get as far as uploading anything. The whole project went on the back burner for some time while my attention went on astronomy stuff. Now I'm broadening my outlook again to other projects like this one and my CCTV surveilance system.

I think it should be possible to make this emulate the F.O. weather station but I shall be concentrating on just getting the system working first then go on to the F.O. emulation.

Yes, I'm an experienced electronics engineer but love the "Blue Peter" approach, making use of things most people throw out I'll post full details of the construction later (if there's interest in this). I even have details of some/most of the 1-wire component layouts so could provide pretty much full constructional details for anyone who would like to copy my design. I would point out though that many of the 1-wire devices are surface mount and require fine soldering skills. I didn't use actual surface mount methods on PCB, but glued the chips upside down on strip board (Veroboard) and wired up using single strands from multi-strand wire, a fine soldering iron tip and magnifier lamp plus "helping hands".

[Gina]

Diagram of the sensors at the top of the mast - wind and light sensors.

1-wire_Wind_and_Light_Sensors.png

[Gina]

Here's a diagram showing the construction of the anemometer using ping pong balls, bottle tops, wooden dowelling and some 6mm plastic sheet. Oh, and a tiny ball bearing, rare-earth magnet and reed switch, and some aluminium tube.. Fixed together with hot melt glue. Wonderful stuff (if you can keep it off your fingers!!!)

1-wire_new_anemometer.png

[Gina]

I've got some photos too - if I can find them, I'll post them

[ColinJS]

This thread is becoming very interesting - thank you.

I received an Arduino kit for Xmas a couple of years back and had just excavated it with a view to adding some extra readings to the existing weather station. But I'm a programmer and what I know about practical electronics would fill - let's be optimistic - a few sides of A4, so rather stuck for where to start. Downloaded a book to my Kindle and this is quite fun to work through. But tweaking it to do what I want and putting it all together seems a bit daunting.

So please keep up the good work!

Cheers,
Colin

[Gina]

OK, I'll post some detailed diagrams or photos of how to connect the Arduino. You might find it useful to get a breadboard and some jumper wires. Then you can easily connect things up and try them out. Not expensive from ebay. In fact there's a great wealth of Arduino compatible parts on ebay as well as the various versions of Arduino board. Amazon have some as well. Of course there are other sources but they are the main ones I use.

An alternative to breadboard and jumper wires is to buy "shields" these are boards that simply plug on to the Arduino board and provide all the connections required for whichever shield you use. In many cases these can be stacked with one shield on top of another. Shields do all sorts of things from LCD display with some button switches (or joystick) to Ethernet interfaces and Data Logging (contains real time clock and SD card slot to provide data storage).

[Gina]

Here's a photo I took of my test setup for the DHT22 humidity and temperature sensor. You can also see a 1-wire digital temperature chip in a little copper P clip plus LCD display and breadboard. The pot controls the LCD contrast. Backlight brightness is controlled from a digital output with PWM.

Arduino_DHT22.jpg

[ColinJS]

Hi Gina,

Thanks for these suggestions. The kit I received included a breadboard, wires and various basic components to allow me to follow the tutorials. It's when I go off-piste I start having trouble. For example, the supplied temperature device is a simple LM35, which will not read below zero. Though having said that, I've seen various suggestions on the net about inserting a couple of diodes in its negative lead to pull the values up a bit. There's the LM335 instead, etc. But the devices you have used sound better, and I was quite encouraged by the apparent simplicity in your photograph.

Hopefully I'll get there in the end. Thanks again,

Colin