Vintage Heathkit 4001 weather station how to split sensors between two consoles

[Bobinphx]

Through a long chain of events, I have restored two heathkit 4001 wired weather station consoles, but I only have one anemometer and wind direction set. I would like to build a circuit that would split the anemometer signal and send it to each of the consoles. The anemometer uses a pair of IR sources and receivers to count interruptions. There are 32 interruptions for each revolution of the wind cups. The signal goes from 5v when there is IR detected and 0v when the IR is blocked. So its pretty much a TTL type pulse. the power for the IR source (led) and detector (photo-resistor) is 5v from the console. I would like one of the consoles to be the "power supply" for the anemometer and the signal to be split and isolated for the second console. I dont think trying to read the signal voltage from a second power supplied console would work. So I am thinking that some sort of isolation / switching circuit is necessary. I do have experience in point to point wiring, bread boarding and even etching my own boards, but I am a little shy on actual design, thus my cry for help! Can anyone give some suggestions as to how to split this signal, and maybe even a suggestion of what devices to use?

Thanks in advance.
Bob in Phoenix.

 

[dorke]

Bob,
What would be the distance between the consoles?

 

[Bobinphx]

The distance from console to console is about 15 feet. the distance to from the "master console" to the anemometer is about 40 feet. The wire being used is cat 5.

 

[dorke]

O.K
The distance is big enough so that parallel connection of the "TTL" lines will probably not work.
The solution could be RS-232(15 feet),
a better solution is using differential line connection(aka RS422):
You will need 4 pairs for direction and another one for speed.

For each input to the console you have one transmitter connected via twisted pair wires to a corresponding receiver terminated with a 120 Ohm resistor.
A total of 5 pairs of twisted wires and 5 resistors at the receiving end.
Using the 26C31 and 26C32 pairs 4 ICs are needed.

1.Use the 26C31(transmitter) at the console feeding ground and +5V to the anemometer.
use the ground and +5V to supply the 26C31.

2.Use the 26C32(receiver) at the other console .
use the ground and +5V to supply the 26C32.

Look at the diagram(only one input is shown)

 

[Bobinphx]

So back in 1986, I read an news story of how the internet would allow collaboration between people. The story told of bigger and better things to come through cooperation and today that is proved to me once again!
Thank you for the time you invested in this question. The fact that you read up on the heathkit 4001 and realized that there were 5 inputs from the direction and speed sensors, really speaks to the love of electronics you have and the greatness of heart that you showed by investing your time to hear a need, learn about the specifics of the need and use your knowledge to fulfill that need for a stranger. For all of that I say thank you. It is now up to me to design, burn, populate and install all of this!!!!!!!

 

[dorke]

Bob,
My pleasure
When I read your post, I said to myself, that heath company did everything
apart from a coffee maker...

I found the 4001 manual at this great site on the Web(agree it has totally changed the world,mostly for good).
Since it said "Digital Weather Computer" and 1978,
I was intrigued and found it was a Mostek MK3780 μcontroller,
One I didn't knew existed... Learning a new/old thing everyday is my reward

I wonder,
Why do you need 2 consoles 15 feet apart?

and,
by all means, do come back for help/advice and when finished/working as well.

 

[GPG]

Since it said "Digital Weather Computer" and 1978,

Better than the site I found. zipped though the images are a little clearer Need to print and stick together to trace anything

 

[GPG]

Leave the white feed to the LEDs disconnected from one unit (power) and blue (transistor supply)
The opto transistors for wind speed/direction feed a buffer with a 10KΩ input so they can be connected in parallel. Connect grounds. Temp sensors should be separate. Should work over 15' ok

 

[Bobinphx]

To answer the question about 15 feet. Our home was built in the 1980s here in phx. Two stories, three bedrooms upstairs and one downstairs. The down stairs has become the office/ computer room. We have the kids, who are adults, computers there so that they can print college work etc. I also have my computer in there and above the computer is the weather station. I dont spend much time in the office, so since I had two consoles, I thought it would be fun to have one in the living room. The console would just sit there on the back corner of the end table where I normally sit, which is about 15 feet away from the office and through one wall. The console is just funky enough to fit in. Our home is a mixture of new and old (mostly 1940s stuff) that I have rebuilt, re-purposed and use daily. For instance, the 60 inch sony tv sits atop a 1940s white oak hand carved buffet. The buffet was in really bad shape. In such bad shape that we couldn't save the legs, so the whole thing is pretty low, only about 18 inches high. The side doors where china would have been stored, now house the AV system, an xbox (kids) and the cable box. The drawers now hold game cds, extra cords and the controllers. We get plenty of compliments on it from friends etc. The whole house is like that. funky, beautiful things, rebuilt, restored and used daily. Its just the style I like and I am lucky because my wife normally likes what I bring home! The only caveat is that if I bring it home, I have to dust it weekly (we do live in a desert after all !!!)

 

[Bobinphx]

Leave the white feed to the LEDs disconnected from one unit (power) and blue (transistor supply)
The opto transistors for wind speed/direction feed a buffer with a 10KΩ input so they can be connected in parallel. Connect grounds. Temp sensors should be separate. Should work over 15' ok

I understand about not powering the leds and transistors by both consoles. Just wanted to be sure about the statement "connect grounds".. is that the console chassis ground or the grounds from the wire connections to the sensors etc.

 

[GPG]

Circuit ground. Its connected at the PSU to the chassis/mains earth

 

[Bobinphx]

thank you, got it!!!