On a sunny day (Thu, 27 Feb 2020 09:08:45 -0400) it happened "Gregg Somes"
 wrote in
:

>Hi, I am trying to use a  2 lead thermistror (not a temp/humidity sensor) with
>RPi 3B+.  Is it possible to wire this without a breadboad?
>
>I cannot find any instructibles or any rpi python code examples anywhere. 
What
>I did so far is connect the ground to one lead, vcc to the other lead using a
Y
>union and put an inline 1-K ohm rewsitor to a third lead as signal [GPIO 23).
>Is there any code magic that can read the digital signal and convert it to
>tempature?
>
>Thanks in advance

First question is what do you want to measure
if it is temperature below / above some point MAYBE,
but thermistors are highly non-linear,
so you want to either measure voltage across your resistor and then calculate
the resistance / and then whatever that represents

AFAIK raspi has no analog input,
so you need what is called an analog to digital converter (board?).

The GPIO as _digital_ input sees a 'logic zero' below some voltage and a 'logic
one' above  some voltage.
Th exact voltage can vary,  also  depends on temperature and production 
spread,
but is somewhere between 0 and 3.3 V

So UNLESS you want o measure a dead cold versus a red hot thermistor is not of
much use.

An external ADC (analog to digital converter) also will need a stable external
reference voltage
I have done all sort of things with temperature sensors using Microchip PICs as
ADC.. connected
to serial port... but that needs some electronics and programming knowledge,
 http://panteltje.com/panteltje/pic/th_pic/

Of course there are other ways, for the fun ..
I wrote a program that converts a digital clock display read by a camera to
time as text,
you could use it to read a multimeter :-)

Anyways to interface and ADC to GPIO takes some electronics knowledge and some
programming knowledge,
preferably C,

But maybe there exists a board 'HAT?'for that?

--- SoupGate-Win32 v1.05