// other
MH-Z19B
True NDIR CO2 sensor
€25.00
avg eur
PWM
UART
Pins
4
Specs
4
Libraries
2
Protocols
2
// wiring → esp32 devkit v1
3V3
EN
GPIO36
VP
GPIO39
VN
GPIO34
GPIO35
GPIO32
GPIO33
GPIO25
GPIO26
GPIO27
GPIO14
GPIO12
GND
GND
GPIO13
ESP32
WROOM-32
devkit v1
USB
VIN
5V
VCC (Vin)
GND
GPIO23
GPIO22
SCL
GPIO1
TX0
GPIO3
RX0
GPIO21
SDA
GPIO19
MISO
GPIO18
SCK
GPIO5
SS
GPIO17
TX2
RX
GPIO16
RX2
TX
GPIO4
GPIO2
GPIO15
sensor pin (left)
sensor pin (right)
unused
// pinout → esp32
| Sensor Pin | ESP32 Connection |
|---|---|
| VCC (Vin) | 5V |
| GND | GND |
| TX | GPIO 16 (RX2) |
| RX | GPIO 17 (TX2) |
// technical specs
Range
0–5000 ppm
Accuracy
±50 ppm + 5%
Voltage
5V
Warmup
3 min
// github libraries
// notes & warnings
NDIR = real CO2. Auto-baseline calibration must be disabled in HVAC environments.
// related sensors · other
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Capacitive Soil Moisture v1.2
Capacitive plant moisture probe
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HX711 + Load Cell
24-bit ADC for load cells (weight)
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INA219
DC current + voltage monitor
€4.50
MQ-135
Air quality (NH3, NOx, CO2, alcohol)
€10.00
MQ-2
Gas sensor (LPG, smoke, CO)
€3.99
Submitted by caio.ricciuti@outlook.com
· Apr 26, 2026