[ Temperature sensor wired to a GPIO pin ]
1. What's a sensor?
A sensor is a small component that converts something from the real world — temperature, light, sound, motion — into an electrical signal your ESP32 can read.
2. Wire the TMP36
The TMP36 has three legs: VCC to 3V3, GND to GND, and OUT to GPIO 4. Double-check the orientation — the flat side of the sensor faces you.
[ TMP36 pinout: VCC, OUT, GND ]
3. Read the temperature
python
from machine import Pin, ADC
from time import sleep
# TMP36 analog sensor on GPIO 4
sensor = ADC(Pin(4))
sensor.atten(ADC.ATTN_11DB) # full 0-3.3V range
while True:
raw = sensor.read() # 0..4095
voltage = raw * 3.3 / 4095 # convert to volts
temp_c = (voltage - 0.5) * 100 # TMP36 formula
print("Temperature:", round(temp_c, 1), "C")
sleep(1)Open the Thonny console. Every second, a fresh temperature in Celsius scrolls by. Touch the sensor with your finger and watch it climb.
What just happened
You used the ESP32's ADC (Analog-to-Digital Converter) to read a voltage and turned it into a real-world value. Combine this with Chapter D's screen code and you have your first digital thermometer!