[turmite]

Hey guys,

My first post in this section and it has nothing to do with cnc. I hope it is ok to post it here. I have had an epiphany (sp) about a instrument I would like to build and need some advise. If you are wanting to use an electric motor as a generator is it the servo or a stepper. I am wanting to use about 5 small motors on stands to read wind velocity and use the output to light different colored leds depending on velocity! Where do I start?
Mike

[Al_The_Man]

Are you wanting to generate power or just read wind speed (anemometer), if the latter you do not really need a generator, but if you do, small DC motors or AC & DC servo's would act as alternators/generators, depending on the load you want to drive. If you want higher power, a cheap source is alternators from an auto wrecker.
Al

[ViperTX]

Why would you want 5 motors....will each have a different size of propellor that requires a different wind speed to turn.....I would suggest a single motor used as a generator...probably use multiple voltage window comparators....Oops...better idea forget the motor just use a propellor mounted on a shaft and then use a hall effect sensor with micro to read the revolutions, or you could use an encoder wheel with an LED interrupter to read the revolutions.....then use the micro to drive a LED bar display or a bank of LEDs.

[turmite]

Hi Al,

Thanks for the reply. Yes and yes! I want to use it as a generator to make the power for the circuitry I want to use to light the leds, and the purpose of this is for a anemometer. I want an array of these, probably 5, spaced evenly every 30 feet/meters. This is to be able to see the differences of the wind velocity within that 150 ft/meter distance. I shoot benchrest and my idea is to be able to have these 5 "units all wired back to the bench to light a series of different colored leds for each unit. It should then be possible to pick a shooting condition when 4 or all of the units are lighting the same color led.

Could a small servo produce enough power to light an led fron up to 150 ft away?

Mike

ps attached is a quick sketch of what I envision the panel looking like.

[Al_The_Man]

No1, I gather you want to power the circuit from the generated power? i.e. no batteries etc?
It does not take much for a small dc servo to put out 5vdc which is the minimum you would need to power logic etc, the only problem I can see is that you would have no power in still conditions, do you want 5 units that are viewed from a distance? if so you will need some large high current leds, so generated power maybe a problem. or are you looking at 5 units at 5 local stations?
The circuit you want can be done with simple logic ics shift registers etc, without the need for micoprocesors.
A circuit can be whipped up if it is exactly known what you are trying to do.
I re-read an see that you want them every 150metres, what is the viewing
distance?
Edit: I read it over and now I think I have it, If you let me know about the power thing I can look at a simple design.
Al

[MrBean]

These links may be of some use to you.

http://www.otherpower.com/anemometer.html

http://www.otherpower.com/toymill.html

http://www.otherpower.com/anemom2.html

http://www.otherpower.com/hamster.html

Regards Terry.....

[turmite]

Hey guys thanks for all the responses. I think I may have been looking for more input than I thought.

ViperTx...I need 5 seperate props so I can get 5 seperate readings. I shoot at 50 yrds and 50 meters. This is a very precise competition that requires you be able to hit a .060" diam. dot at both of those distances for a perfect score. Of course no one has yet shot the perfect score but this might help!

Al after reading your last response I gave some though to your statement about the need for the motors to produce the power. I think battery power would be ok without having the motors to generate it. It does need to be small and compact thought. Would it make the design easier to use batteries?

I also thought about how I worded my distances and there may be a bit of confusion there, in fact there may have been a bit of confusion on my part. I would need the "motors/props" at the following distances. 7-8 yds/meters, 15, 22, 30, 42 yds/meters. If all of the leds indicated one color I would know that the velocity was the same through the complete path of the of the bullet. You would have to see how much effect a 10 mph breeze has on a 40gr bullet traveling slightly sub-sonic. When all the lights are the same color...ummmm...and the wind is all from the same direction pull the trigger.

MrBean thank you for your links. I will check them out in a couple of days. My mother is in her last days and I am needing to spend all the time I can with her, even though she doesn't know I'm there. Rigid Parkinsons.

Mike

[vladdy]

Hmmm...seems like a lot of work..I use 3 foot strips of curtain material, add a paper clip at 6, 18 and the end.. gives a pretty good idea of wind velocity, as well as gusting downrange..
kind of helps when you pull just a tad, then at least you have something to blame ...

just out of curiosity, what class ? 10lb? or?

re-read your post.. 50m is 22? no?

[Al_The_Man]

For accuracy, you would need small anemometers, that are very friction free, the problem with using motors is that if you place any kind of load on them, especially if it is a varying load the output will be non linear and not very accurate, I built a simple one some years ago that the principle of my kids school wanted built for a weather station, they did not have the budget for a commercial one. The anemometer drove a slotted disk that used an opto interupter for reading head. The bottom of the shaft rested on a 3/8" ball bearing so the friction was minimal.
Al

[ViperTX]

Hmmmm....sounds strangely familiar.....