NEOE-IOT-Kit-7: Smart Home IoT digital room air sensor with MQ-135 and NodeMCU. Arduino programming. MQTT-compatible for connection to Home Assistant. Structure variant "Breadboard".
Adequate ventilation is important for health. The MQ-135 sensor monitors the room air. To put it more precisely: According to the manufacturer's data sheet, it monitors the room air for CO2, alcohol, benzene, NOx, and NH3.
The MQ-135 sensor is available in two versions:
- MQ-135 standalone for soldering in printed circuit boards
- MQ-135 module to plug into breadboards
The "MQ-135 Module to plug into breadboards " has its own logic and can therefore also output digital values. The module has a potentiometer to set the threshold value for the digital output.
At the digital pin, the sensor outputs the value 1 (everything OK) or the value 0 (bad air) in the Arduino sketch via digitalRead, depending on whether the threshold value set on the potentiometer is exceeded.
- If the room air is OK, the indicator LED lights up green.
- Should the room be ventilated, the indicator LED flashes red.
The calibration using the potentiometer is based on the subjective air quality perception. For example, by adjusting this so that the indicator LED shows green in fresh air (outside) and flashes red in an apartment that has not been ventilated for a long time.
The digital values are also output via MQTT and can thus be transferred to common smart home systems (such as Home Assistant).
This is a kit for hobbyists who are enthusiastic about the Internet of Things (IoT). No responsibility can therefore be assumed for the reliable functionality of the air quality measurement. The MQ-135 sensor itself gets warm and should therefore only be operated when you are present. In addition, the MQ-135 sensor has a burn-in time of several hours, during which the values can still fluctuate.
- IoT kit as a kit for a digital room air sensor. Monitoring of the data via MQTT by smart home systems (such as Home Assistant) is possible.
- Scope of delivery: D1 mini NodeMCU, MQ-135 sensor, 400 hole breadboard, 40pin jumper cable - 10cm - Male to Male, 5mm RGB - LED 4pins - common cathode, 3 x 220 Ohm resistors. Depending on availability, the kit is delivered with the D1 mini V2 NodeMCU (see illustration) or D1 mini V3 NodeMCU (visually different).
- The setup requires certain electronics and computer skills. The NodeMCU must first be soldered before inserting it into the breadboard. A computer with an installed Arduino IDE is required to install the software.
- We deliberately chose small components (mini-NodeMCU, small breadboard, short jumper cables) so that the built-up sensor kit looks as elegant as possible and is also accepted by the other roommates / family members. The breadboard has self-adhesive tape on the back and can e.g. be attached to the wall or in a self-designed housing (there are no limits to creativity).
- Required separately: soldering iron, USB charger or power bank, computer, smart home system (e.g. Home Assistant on a Raspberry Pi).