# anemometer using 7 segment leds

Discussion in 'Electronic Basics' started by squidwxrd, Nov 7, 2003.

1. ### squidwxrdGuest

I'm putting together a anemometer from scratch
for a project in a digital class.
I have to use TTL chips.
Basically I want to take the signal from a motor
that is being turned by wind (analog), then convert
the signal to digital and read the wind speed in
mph using two 7-segment LEDs.

a. What is a good way to convert from analog to digital?
b. How do I take a 16 - bit # and transfer it to 2 7-segments,
i.e. from 00010001 to 1, 7 on 2 7-segment leds?

I want to use a shift register from an ADC and possibly
toss a latch in the mix. I would like the speed to be read
instantaniously but since I'll be using a 555 timer to drive
the clock pulses, it may be better to use 1-second samples.

thanks for any help

Kevin

2. ### Lord GarthGuest

Skip the A/D and build a photo intrupter / counter. If you convert 1 MPH
into
IPS you'll find 5280 feet/hour is equal to 17.6 inches / second. A disk
whos
circumference is 17.6 inches will directly read out in MPH if the photo
interuptions are counter for 1 second. Your circuit simply needs to do
three
things in sequence:
1) reset the counter
2)count the number of disk rotations in 1 second
3)latch this count
start over with step 1

That disk works out to be about only 5.6 inches in diameter.

You could count over 10 seconds and move the decinal point for more
resolution.

3. ### John GGuest

If you use a "motor" to generate your signal you may find the drag is too
much for low wind velocities and it would be better to use a disk and photo
cell or some other sensor that produces NO drag.
Just a suggestion from Experience!

4. ### squidwxrdGuest

thankyou. I'll give it a shot.

tootles

5. ### squidwxrdGuest

thanx for the help.

tootles

6. ### Larry GreenGuest

I came across an article on the web recently for a kit that used ultrasonic
transducers in an anemometer. Unfortunately I didn't save the link but I
believe it was an article in a UK electronic hobby magazine. Try a Google
search for 'ultrasonic anemometer'.

Larry