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I'm looking for an inexpensive temperature sensor which is non reliant on the input voltage to return an analog reading back or some sort of digital signal. Accuracy is not very important, for instance +/- 4 C is fine. The lm35 I have been using jumps from 25 to 70 degrees regularly with changes in circuit load.

My other option is to add a separate voltage regulator, but I am trying to avoid that if possible! Thanks!

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    Switching to digital temperature sensors such as DHT22 or BMP sensors would be a great idea as output will be less fluctuated and it is often independent of minor fluctation. – goddland_16 Jun 29 '17 at 4:35
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The DS18B20 is a temperature sensor with a digital interface (1-Wire). It works at 3.3 to 5V and the cable length can be a number of meters. It is accurate to 0.5°C.

The DS18B20 is probably the most used temperature sensor for Arduino projects. Its price starts at less than a dollar/euro. You only need the DS18B20, a pullup resistor of 10k and a digital pin.

In the Arduino IDE, go to the Library Manager and search for 'onewire'. Install the "OneWire by Jim Studt, Tom Pollard, ... Paul Stoffregen, ...".
Then search for 'dallas' and install "DallasTemperature by Miles Burton, ...".
The OneWire library on its own can read the temperature of the DS18B20, but the DallasTemperature makes it easier to use. Look for the examples of the DallasTemperature in the Arduino IDE to start with the DS18B20.

The 1-Wire is a bus, you can add more DS18B20 sensors to the same wire. The DallasTemperature library has two options. Select either a sensor by index, or by its ID. Every DS18B20 has a unique ID inside the sensor.

Sometimes an analog temperature sensor has specific advantages, for example a ntc temperature sensor or a thermocouple sensor. For normal indoor or outdoor usage, the digital temperature sensors are far more easier to use.

Why measure only the temperature ? If you want the baromic pressure and humidity as well, the BME280 has it all. Its temperature accuracy is not very accurate, it is only ±1°C.

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