# anemometer using 7 segment leds

S

#### squidwxrd

Jan 1, 1970
0
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

L

#### Lord Garth

Jan 1, 1970
0
squidwxrd said:
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

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.

J

#### John G

Jan 1, 1970
0
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!

S

#### squidwxrd

Jan 1, 1970
0
Lord Garth said:
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.
thankyou. I'll give it a shot.

tootles

S

#### squidwxrd

Jan 1, 1970
0
thanx for the help.

tootles

L

#### Larry Green

Jan 1, 1970
0
John G said:
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!

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

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