Author Topic: Concept for anemometer......  (Read 10019 times)

Offline John Hill

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Concept for anemometer......
« on: December 19, 2010, 04:18:21 PM »
An anemometer to show the wind speed and direction is always an interesting project!  This project is for a simple device which displays the wind speed and direction on your PC or maybe that old laptop you have on the top shelf.

The concept is simple:
An old PC keyboard is ratted retaining only the small printed circuit board and the attached cable.  The wind direction vane  is connected to a multi position switch which you modify to allow 360 degree rotation.  The wind speed rotor is connected to a simple switch (a magnet and reed would be good).

The direction switch is wired each position to pads on one edge of the keyboard PCB.  The common connection from the switch goes to the wind speed switch then back to another connection on the PCB.

If we plug that keyboard into a PC and turn the speed rotor the PCB will send a series of character to the PC and if we move the direction vane the character will change.

All you software has to do is translate character to direction, you will easily be able to find a 12 position switch so that will be 30degree resolution which is plenty good enough for this sort of instrument.  Counting the number of characters per time interval will give you the speed.

You will probably have to extend the cable for the keyboard somewhat!

Have fun.
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Offline kwackers

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Re: Concept for anemometer......
« Reply #1 on: December 19, 2010, 05:58:54 PM »
What about keyboard auto repeat? Can you turn that off?

Offline John Hill

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Re: Concept for anemometer......
« Reply #2 on: December 19, 2010, 06:26:34 PM »
What about keyboard auto repeat? Can you turn that off?

I believe you can turn that off in Windoze in the disability options.
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Offline Bogstandard

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Re: Concept for anemometer......
« Reply #3 on: December 19, 2010, 11:50:30 PM »
Still not as easy as the piece of string for a weather station.

Holding onto the top end.

If it is dry and perfectly still, it's a nice day.

If it is swinging side to side, it is windy.

If there is water dripping off the end, it is raining.

If you can turn it the wrong way up and it is still stiff, it is freezing.


What more do you need?


Bogs
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Offline John Hill

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Re: Concept for anemometer......
« Reply #4 on: December 20, 2010, 12:29:58 AM »
So true Bogs but this is Madmodders, you should post that one on the macrame board! :med:
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Offline crabsign69

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Re: Concept for anemometer......
« Reply #5 on: December 20, 2010, 12:15:46 PM »
 :worthless:      :worthless:      im interested   

Offline John Hill

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Re: Concept for anemometer......
« Reply #6 on: December 20, 2010, 01:10:02 PM »
:worthless:      :worthless:      im interested   

Sorry:-

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Offline John Hill

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Re: Concept for anemometer......
« Reply #7 on: December 20, 2010, 01:11:23 PM »
CS69, you mean you want me to actually make one of these?

It will take a few hours to get organised... :med:
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Offline BillTodd

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Re: Concept for anemometer......
« Reply #8 on: December 20, 2010, 01:42:17 PM »
How about....

Two magnets (or a light source) attached to a disk that rotates with the anemometer.

Two reed switches(or optical sensors), one fixed to body operated by one of the magnet, one rotating on a disk moving with the wind vane operated by the other magnet.

The output of the fixed switch (or sensor) can be connected to the Rxd (data receive) of a PC serial port, Each time it is activated it will generate a comport interrupt , which can be counted and integrated to give the wind speed.

The output of the rotating vane switch can be taken to another serial port input (e.g. DSR - data set ready ?). The software has to time the delay between the RXD interrupt and the DSR pulse to determine the wind direction.

BTW this is not a new idea  I saw this scanning system in a anemometer some years ago in an electronics mag.

Bill

[edit] it occurs to me that there might be a way to channel the magnetic field (or light) to the centre of the vane thus avoiding the need for slip-rings and a second magnet.
« Last Edit: December 20, 2010, 02:43:56 PM by BillTodd »
Bill

Offline benji

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Re: Concept for anemometer......
« Reply #9 on: December 20, 2010, 02:35:42 PM »


What more do you need?


Bogs

How long should the piece of string be?  ::)

Offline Alan Haisley

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Re: Concept for anemometer......
« Reply #10 on: December 20, 2010, 05:35:42 PM »
So true Bogs but this is Madmodders, you should post that one on the macrame board! :med:

Ah, but there needs to be a pivoted clamp and pivot arm. Otherwise how would you hold it or invert to check for freezing?  :dremel:

Alan

Offline DMIOM

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Re: Concept for anemometer......
« Reply #11 on: December 21, 2010, 04:23:36 AM »
Ah, but there needs to be a pivoted clamp and pivot arm. Otherwise how would you hold it or invert to check for freezing?  :dremel:

Alan

   :smart:

Ahh ... this all starts to make sense now, we can put some of the jigsaw together of Dr Bogs's invention.  All this work, both on swing-up toolholders and on motorised rotabs wasn't really for threading or machining, it was to provide angular reciprocation so the angle of the dangle of the string can be measured ; and his work on ultra fine nozzles wasn't really for mist cooling but to provide a precision calibration of the string's deflection!

Dave   :coffee:

Offline Bogstandard

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Re: Concept for anemometer......
« Reply #12 on: December 21, 2010, 04:25:41 AM »
Just to answer a few questions about this revolutionary piece of equipment.

Quote
How long should the piece of string be?

Actually, it has to be made precisely the correct length for the part of the world you live in.

For an area that suffers from strong winds, it doesn't need to be too long as you could end up hanging yourself, as the wind blows it everywhere, or to counteract that effect, a one pound weight on the end may cure the problem. But that is only a theoretical assumption, field trials should give more understanding of what is really required.

For wet or dry countries, for wet, you can have it much longer, as the drips will easily reach the end, but say in a desert region, a lot shorter, otherwise you will be waiting forever for the drips to get to the bottom to drop off.


Quote
Ah, but there needs to be a pivoted clamp and pivot arm. Otherwise how would you hold it or invert to check for freezing?

It has been found during field trials that the thumb and forefinger is perfectly adequate for a portable version of this instrument, and it has also been found that either left or right hand digits can be used without any detrimental effects to the readings obtained. The use of gloves in such a cold environment is thoroughly recommended, as removing string from between frozen to it digits can be rather painful.

One major point regarding safety must be raised (the dreaded H&S). If the area to be checked is both freezing AND windy, special care must be taken to keep a vice like grip on the instrument. There are cases where people and objects have been impaled by lengths of frozen string.

For lab work, a small crocodile clip has been found perfectly adequate, if wind speeds are kept fairly low.


Bogs


BTW, do you really want to keep all this bullsh going?

If you don't try it, you will never know if you can do it.

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Offline Bernd

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Re: Concept for anemometer......
« Reply #13 on: December 22, 2010, 01:55:08 PM »
I found a link in my favorites while looking for something else.

It's a link to building an anemometer. Might be helpful to somebody that wants to build one. LINKY HERE

Bernd
« Last Edit: December 22, 2010, 10:20:11 PM by Bernd »
You can't fix "STUPID".

Offline Bogstandard

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Re: Concept for anemometer......
« Reply #14 on: December 22, 2010, 02:02:40 PM »
Link doesn't work for me Bernd.

John
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Offline BillTodd

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Re: Concept for anemometer......
« Reply #15 on: December 22, 2010, 02:10:14 PM »
You need to remove the } from the end of the link Bernd

http://www.infidigm.net/projects/windmeter/

Bill
Bill

Offline Bernd

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Re: Concept for anemometer......
« Reply #16 on: December 22, 2010, 10:21:34 PM »
Thanks Bill. I fixed it in my orginal post. Works now.

Sorry guys, fat finger syndrome.  :wack:

Bernd
You can't fix "STUPID".

Offline John Hill

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Re: Concept for anemometer......
« Reply #17 on: December 23, 2010, 12:10:41 AM »
Hmmm, I am please so many people have chosen to respond to my topic with variation of an anemometer.   

However, and this is my fault for inappropirate choice of topic title, what I really wanted to do was to draw attention to the potential of using a pukaru keyboard for simple interfacing to PC etc.

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tumutbound

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Re: Concept for anemometer......
« Reply #18 on: December 23, 2010, 05:09:48 AM »
I'll reply on topic then.  ::)

I can see no reason why your scheme should not work for wind direction.
I'm not sure if it will work for wind speed, it would depend on how quickly the keyboard can respond to a key press.
How many RPM will an anemometer get up up to in a strong wind?

Well mostly on topic.
Here a high tech option with no moving parts.
« Last Edit: December 23, 2010, 05:11:57 AM by tumutbound »

Offline BillTodd

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Re: Concept for anemometer......
« Reply #19 on: December 23, 2010, 10:05:32 AM »
The principle problem with using a keyboard is the way its input is handled by the operating system. In a multi-tasking system like windows or linux the key inputs will be passed to whatever application has the current focus, so unless you are prepared to dedicate a pc to the task of wind speed monitoring, it's not an idea solution.

Serial inputs (com ports) are useful because the driver usually takes care of unused data without causing too many problems. Parallel ports (printer ports) can also be used but usually require some extra hardware knowledge. Sadly both ports are disappearing from new machines, as they are replaced by USBs.  USBs requires a ridiculous amount of software at both ends to use natively (i.e. as a Human Interface Device), but at least there are cheap USB-serial adapters that turn them into comports.

Bill
Bill

Offline andyf

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Re: Concept for anemometer......
« Reply #20 on: December 23, 2010, 10:28:24 AM »
This is off John Hill's topic. because he is more concerned with interfacing a pukaru keyboard ( :scratch: never heard of one before) to a PC, but a simple anenometer could made with the pitch circle of its vanes the same diameter as a small cycle wheel. Then, with the actuating magnet mounted on one of the spokes of the anenometer, a cycle speedo could be used to display the speed either in mph or kph.

Andy
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I've cut the end off it twice, but it's still too short

Offline John Hill

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Re: Concept for anemometer......
« Reply #21 on: December 25, 2010, 04:07:21 AM »
The principle problem with using a keyboard is the way its input is handled by the operating system. In a multi-tasking system like windows or linux the key inputs will be passed to whatever application has the current focus, so unless you are prepared to dedicate a pc to the task of wind speed monitoring, it's not an idea solution.

Thats true Bill but what you can do is write a keyboard 'hook'  which will see every message between the hardware drivers and winderz proper.  You can also at that point (in current versions of winderz) identify which keyboard the message came from.


Quote
Serial inputs (com ports) are useful because the driver usually takes care of unused data without causing too many problems. Parallel ports (printer ports) can also be used but usually require some extra hardware knowledge. Sadly both ports are disappearing from new machines, as they are replaced by USBs.  USBs requires a ridiculous amount of software at both ends to use natively (i.e. as a Human Interface Device), but at least there are cheap USB-serial adapters that turn them into comports.

Bill

Serial ports are quite useful for the pc modder (but not as much as they used to be for W95 and before). They are particulary useful having bi-polar output and I suppose they could easily be used to drive an H bridge but there are not many lines available for output,  Txd, Rts, Dtr and I think thats about it, inputs are Rxd, Cts, Dsr, Dcd, Ri.  Of course if you go further and use a UART in your project you can get 8 bits in and out plus  some of the control lines.  Serial ports used to be very useful when it was still easy to write interrupt service routines that would be handled immediately not when the operation system go around to it, it is much harder nowadays.

But serial ports are not what I was trying to invoke madmodder interest in.

I would not recommend parallel (printer) ports for madmodder hacks as it seems to be very easy to kill the PC port circuitry.

The point I was trying to demonstrate is that using a keyboard pcb ('pukaru' means broken in this country) gives an easy method of sending several different messages to the program, the demonstration example I gave used a multi postion switch to indicate wind direction (a cheap and readily available 12 position switch would give 30 degree visions of the compas).  I choose an anemometer as an example as I thought people would easily understand what is required and if you were prepared to dedicate a PC to the task the software could be written in the most simple of languages by an absolute beginner,  the anemometer would be the exercise to take right after writing one's first 'Hello World' program.

I agree that the USB protocols are not for the beginner computer modder but USB has its place, for example in my anemometer example I would look for a USB keyboard to hack.

John
« Last Edit: December 25, 2010, 04:14:58 AM by John Hill »
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