ESP8266 NodeMCU-Based Environmental Monitoring System with Multiplexed Sensors
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Circuit Documentation
Summary
The circuit in question is designed to interface an ESP8266 NodeMCU microcontroller with a variety of sensors and a multiplexer. The ESP8266 NodeMCU is responsible for controlling the multiplexer and reading data from the sensors, which include a rain sensor, a pH meter, and an SMA sensor. The multiplexer allows the microcontroller to interface with multiple sensors using fewer GPIO pins by selecting which sensor to read at a given time.
Component List
ESP8266 NodeMCU
- Description: A Wi-Fi capable microcontroller module based on the ESP8266 chip.
- Pins: D0, D1, D2, D3, D4, 3V3, GND, D5, D6, D7, D8, RX, TX, A0, RSV, SD3, SD2, SD1, CMD, SD0, CLK, EN, RST, VIN
SparkFun 74HC4051 8-Channel Mux Breakout
- Description: An 8-channel multiplexer that allows a single microcontroller pin to select one of 8 channels.
- Pins: Y7, Y6, Y5, Y4, Y3, Y2, Y1, Y0, GND, VCC, VEE, !E!, S2, S1, S0, Z
Rain Sensor
- Description: A sensor that detects rain by measuring the resistance between two pads.
- Pins: AO, DO, GRD, VCC
pH Meter
- Description: A sensor used to measure the pH level of a liquid.
- Pins: Signal, VCC, GND
SMA Sensor
- Description: A generic sensor with an analog output.
- Pins: A0, D0, GND, VCC
Wiring Details
ESP8266 NodeMCU
- D1 connected to SparkFun 74HC4051 S0
- D2 connected to SparkFun 74HC4051 S1
- D5 connected to SparkFun 74HC4051 S2
- GND connected to GND of all components
- 3V3 connected to SparkFun 74HC4051 VCC
- A0 connected to SparkFun 74HC4051 Z
- VIN connected to VCC of all sensors
SparkFun 74HC4051 8-Channel Mux Breakout
- S0 connected to ESP8266 NodeMCU D1
- S1 connected to ESP8266 NodeMCU D2
- S2 connected to ESP8266 NodeMCU D5
- !E! connected to ESP8266 NodeMCU GND
- GND connected to ESP8266 NodeMCU GND
- VCC connected to ESP8266 NodeMCU 3V3
- VEE connected to ESP8266 NodeMCU GND
- Z connected to ESP8266 NodeMCU A0
- Y2 connected to pH Meter Signal
- Y1 connected to SMA Sensor A0
- Y0 connected to Rain Sensor AO
Rain Sensor
- AO connected to SparkFun 74HC4051 Y0
- GRD connected to ESP8266 NodeMCU GND
- VCC connected to ESP8266 NodeMCU VIN
pH Meter
- Signal connected to SparkFun 74HC4051 Y2
- GND connected to ESP8266 NodeMCU GND
- VCC connected to ESP8266 NodeMCU VIN
SMA Sensor
- A0 connected to SparkFun 74HC4051 Y1
- GND connected to ESP8266 NodeMCU GND
- VCC connected to ESP8266 NodeMCU VIN
Documented Code
No code was provided for the microcontrollers in the circuit. The documentation of the code would typically include a description of the functionality, setup, and main loop, along with any functions or libraries used. Since no code is available, this section cannot be completed. If code becomes available, it should be added here with appropriate comments and explanations.