Required Components

About the Temperature Sensor

Sometimes, a thermistor is used as a temperature sensor.
While thermistors are inexpensive and easy to obtain, their conversion formula is complex.
In this tutorial, we will use a more expensive but simpler IC (LM61CIZ) with a straightforward calculation formula.
The LM61CIZ outputs 600mV when the temperature is 0°C.
This is to prevent the output voltage from becoming negative even when the temperature is negative.
The LM61CIZ has a change of 10mV per degree Celsius.
For +25°C: 600 + 250 = 850mV
For -25°C: 600 - 250 = 350mV
Also, this sensor can be used without using a voltage divider resistor, and can be used by simply connecting the power supply.
The power supply also supports a wide range of 2.7～10V, and the output voltage remains at 600mV at 0°C regardless of the power supply voltage.

Electronic Circuit

Circuit Diagram

Breadboard Circuit

Program

Program to measure temperature 

TEMP_ADC = 6
adc = ADC.new()
adc.ch(TEMP_ADC)
temp = 0
while true
  adc.start
  v = adc.read_v
  adc.stop
  temp = (v-0.6)*1000/10
  puts("temp:" + temp.to_s)
end

Task: