TMP36 Temperature Sensor with an Arduino Uno
A low-voltage analog temperature sensor with a 0.5 V offset, so it reads below freezing on a single supply.
The TMP36 runs from 2.7 V to 5.5 V, so on an Arduino Uno it can use the 5V pin as wired here, with VOUT on A0. Its output does not follow the supply, while the Uno's default analog reference is the 5 V rail, so the accuracy of each reading depends on how close the Uno's 5 V really is to 5.0 V.
Wiring the TMP36 Temperature Sensor to the Arduino Uno
Pin by pin.
| TMP36 Temperature Sensor | Arduino Uno |
|---|---|
| VCC | 5V |
| VOUT | A0 |
| GND | GND |
What to know on the Arduino Uno
- The sketch assumes the ADC reference is 5.0 V. If the Uno's USB 5 V is actually 4.8 V, a sensor at 25 °C (0.75 V) reads as 0.78 V, about 28 °C. Measure your 5V pin and put that value in ADC_VREF.ADI TMP35/36/37 datasheet Rev. F, p. 8; Microchip ATmega328P datasheet DS40002061B, p. 2
- One step of the Uno's ADC on 5 V is about 4.9 mV, nearly half a degree for a 10 mV/°C sensor, so the sketch averages eight readings.ADI TMP35/36/37 datasheet Rev. F, p. 3; Microchip ATmega328P datasheet DS40002061B, p. 2
- For a steadier reference, wire the Uno's 3.3V pin to AREF and call analogReference(EXTERNAL) before any analogRead(): about 3.2 mV per step, and the TMP36's whole -40 to +125 °C output still fits under 3.3 V. Set ADC_VREF to 3.3.Arduino language reference, analogReference(); ADI TMP35/36/37 datasheet Rev. F, p. 1
- Its output drives 50 µA at most, so keep VOUT's wire to A0 short and put nothing else on it.ADI TMP35/36/37 datasheet Rev. F, p. 3
TMP36 Temperature Sensor code for the Arduino Uno
Compiled for arduino:avr:uno on 2026-10-29.
// TMP36 Temperature Sensor on Arduino Uno: wiring and a free simulation at https://www.tinkered.ai/components/tmp36/arduino-uno
const int VOUT_PIN = A0; // TMP36 VOUT
const float ADC_VREF = 5.0; // the Uno's analog reference: its 5 V
const float ADC_STEPS = 1024.0; // 10-bit ADC
void setup() {
Serial.begin(9600);
}
void loop() {
long sum = 0;
for (int i = 0; i < 8; i++) sum += analogRead(VOUT_PIN);
float volts = (sum / 8.0) * ADC_VREF / ADC_STEPS;
float tempC = (volts - 0.5) * 100.0; // 0.5 V at 0 °C, 10 mV per °C
float tempF = tempC * 9.0 / 5.0 + 32.0;
Serial.print("Temperature: ");
Serial.print(tempC, 1);
Serial.print(" C ");
Serial.print(tempF, 1);
Serial.println(" F");
delay(1000);
}
TMP36 Temperature Sensor on the Arduino Uno: questions
Why is my TMP36 reading a few degrees off on the Arduino Uno?
The sketch's conversion assumes exactly 5.0 V, but USB often gives a little less. Measure the Uno's 5V pin and use that as ADC_VREF, or reference the ADC to the 3.3V pin through AREF.
Can I power the TMP36 from the Uno's 3.3V pin?
Yes. It runs from 2.7 V to 5.5 V (ADI datasheet, p. 3), and its 50 µA is nothing for the 3.3V pin.
How precise is the TMP36 on an Uno?
The Uno resolves about 0.5 °C per ADC step on its 5 V reference, about 0.3 °C with 3.3 V on AREF. The sensor itself is ±3 °C max at 25 °C for the common G grade (ADI datasheet, p. 3), so calibrate against a known temperature.
Keep going
This guide as plain Markdown. /components/tmp36/arduino-uno.md