From the archives: a wind chill meter

[bitrex]

The wind chill tonight is lovely! Gusting to 50 mph at 22F to begin with.

Here's a digital wind chill calculator, no software here:

<http://www.seekic.com/uploadfile/ic-circuit/2009710213732883.gif>

"PROM Converts Weather Data for Wind-Chill Index Display, Electronics,
Jan. 5, 1978, p 158-159."

Looks like there's an error on the schematic, both the nor gates and or
gates are labeled LS02, or they forgot the dots on the left.

 

[bitrex]

On 1/17/20 2:51 AM, bitrex wrote:

The wind chill tonight is lovely! Gusting to 50 mph at 22F to begin with.

Here's a digital wind chill calculator, no software here:

http://www.seekic.com/uploadfile/ic-circuit/2009710213732883.gif

"PROM Converts Weather Data for Wind-Chill Index Display, Electronics,
Jan. 5, 1978, p 158-159."

Looks like there's an error on the schematic, both the nor gates and or
gates are labeled LS02, or they forgot the dots on the left.

bonus points, redesign with CMOS logic and run the circuit off the
spinning of the anemometer:

<https://www.analog.com/en/products/ltc3588-1.html>

 

[Rick C]

On Friday, January 17, 2020 at 2:51:06 AM UTC-5, bitrex wrote:

The wind chill tonight is lovely! Gusting to 50 mph at 22F to begin with.

Here's a digital wind chill calculator, no software here:

http://www.seekic.com/uploadfile/ic-circuit/2009710213732883.gif

"PROM Converts Weather Data for Wind-Chill Index Display, Electronics,
Jan. 5, 1978, p 158-159."

Looks like there's an error on the schematic, both the nor gates and or
gates are labeled LS02, or they forgot the dots on the left.

Doesn't matter. They drive inputs to a ROM which may be programmed to compensate or the wrong part number might have been used. I don't recall an OR gate, LS32 maybe? They also don't show the Add/Sub and Cin connections for U3 and U5. I assume the Add/Sub is the same as for U2 and U4 respectively, but the Cin should come from the lower digit, no?

I guess it worked and was likely a pretty cool gadget at the time. No photos?

--

Rick C.

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