The Wi-Fi version of the irrigation build. Same control loop, moved onto a NodeMCU so the moisture data can leave the bench and reach a dashboard or a phone.
What it does
Everything runs at 3.3V, the OLED moves to D1 and D2, and the single ADC pin is reserved for the soil probe. Once the local loop works, publishing to Firebase or Blynk is the next step in class.
Circuit connections
| Connection | Arduino pin |
|---|---|
| Soil moisture AO | A0 |
| OLED SDA | D2 (GPIO4) |
| OLED SCL | D1 (GPIO5) |
| Buzzer | D6 (GPIO12) |
| Relay IN (pump) | D7 (GPIO13) |
| Module power | 3.3V + GND |
Bench note: Do not power the relay coil from the NodeMCU 3.3V rail. Use the board 5V (VIN) pin or an external supply, or the ESP will reset every time the pump kicks in.
Libraries used
Wire.hAdafruit_GFX.hAdafruit_SSD1306.hGet the parts
Two ways to build this, and you can choose either. Take the complete kit in one box, or buy only the individual components you are missing. Both use the normal shop cart.
Option 1 — Complete kit
₹2,999eARgle Smart Agriculture Project Kit — everything needed, boxed, with the quick-start card and reference sketches.
Add kit to cartOption 2 — Individual components
₹1,221The full parts list is ₹1,221 for all 9 items. Add them all at once, or pick single items from the list below.
- ESP8266 NodeMCU V3 Wi-Fi Development BoardCB-ESP8266-NM₹299Add to cart
- Capacitive Soil Moisture Sensor v2.0CS-SOIL₹129Add to cart
- 0.96 inch OLED Display 128×64 I2C (SSD1306)CD-OLED-096₹199Add to cart
- 2-Channel 5V Relay Module with OptocouplerCM-RELAY-2₹119Add to cart
- 5V Submersible Water Pump with TubingCMO-PUMP-5V₹149Add to cart
- Active and Passive Buzzer PairCA-BUZZ₹49Add to cart
- 400 Point Solderless BreadboardCA-BB-400₹59Add to cart
- Jumper Wire Set 120 Pieces (M-M, M-F, F-F)CA-JUMPER-120₹149Add to cart
- USB A to Micro-B Data Cable (1m)CA-USB-MICRO₹69Add to cart
Already own the board or the display? Skip them — the sketches do not care where the parts came from.
Source code
Every sketch on this page is open source. Clone it, change it, break it, tell us what you learned.
Want to be taught this, not just handed the code?
We run this as a mentor-led session for schools, colleges and individual learners, online or at our centre. Tell us what you want to build.