Circuit Documentation

Summary

This circuit is designed to interface an Arduino Pro Mini with an NRF24L01 wireless transceiver module, powered by a 18650 Li-ion battery. The circuit includes a 3.3V voltage regulator to ensure the NRF24L01 and the Arduino Pro Mini are supplied with the correct voltage. A humidity sensor (YL-69) is also connected to the Arduino for environmental sensing. The power supply can be controlled by a rocker switch, and electrolytic capacitors are used for voltage smoothing.

Component List

NRF24L01 Wireless Transceiver Module

• Description: A wireless transceiver module that operates at 2.4 GHz.
• Pins: IRQ (not used), MOSI, CSN, VCC (3V), GND, CE, SCK, MISO.

18650 Li-ion Battery

• Description: A rechargeable battery providing the power source for the circuit.
• Pins: -, +.

Rocker Switch

• Description: A switch to control the power supply to the circuit.
• Pins: 1, 2.

3.3V Voltage Regulator

• Description: Regulates input voltage down to a stable 3.3V output.
• Pins: GND, OUT, Vin.

Electrolytic Capacitor

• Description: Provides voltage smoothing in the power supply circuit.
• Pins: -, +.
• Properties: Capacitance: 0.00047 Farads.

Arduino Pro Mini

• Description: A compact microcontroller board based on the ATmega328.
• Pins: DTR, TXO, RXI, VCC, GND, A4, A5, RAW, RESET, A3, A2, A1, A0, SCK, MISO, MOSI, D10, D9, D8, D7, D6, D5, D4, D3, D2.

Humidity Sensor (YL-69)

• Description: A sensor for detecting humidity levels in the soil.
• Pins: A0, D0, GND, VCC.

Wiring Details

NRF24L01 Wireless Transceiver Module

• MOSI connected to Arduino Pro Mini MOSI
• CSN connected to Arduino Pro Mini D8
• VCC (3V) connected to 3.3V regulator OUT
• GND connected to system ground
• CE connected to Arduino Pro Mini D7
• SCK connected to Arduino Pro Mini SCK
• MISO connected to Arduino Pro Mini MISO

18650 Li-ion Battery

• (-) connected to system ground
• (+) connected to the input of the rocker switch

Rocker Switch

• Pin 1 connected to the positive terminal of the 18650 Li-ion Battery
• Pin 2 connected to the Vin of the 3.3V voltage regulator and the positive side of the electrolytic capacitor

3.3V Voltage Regulator

• GND connected to system ground
• OUT connected to VCC of NRF24L01 and Arduino Pro Mini
• Vin connected to the output of the rocker switch and the positive side of the electrolytic capacitor

Electrolytic Capacitor

• (-) connected to system ground
• (+) connected to the output of the rocker switch and the Vin of the 3.3V voltage regulator

Arduino Pro Mini

• VCC connected to 3.3V regulator OUT
• GND connected to system ground
• SCK connected to NRF24L01 SCK
• MISO connected to NRF24L01 MISO
• MOSI connected to NRF24L01 MOSI
• D8 connected to NRF24L01 CSN
• D7 connected to NRF24L01 CE
• D3 connected to Humidity Sensor YL-69 A0

Humidity Sensor (YL-69)

• A0 connected to Arduino Pro Mini D3
• VCC connected to 3.3V regulator OUT
• GND connected to system ground

Documented Code

Arduino Pro Mini (Instance 1)

File: sketch.ino

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Arduino Pro Mini (Instance 2)

File: sketch.ino

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Note: The provided code for both instances of the Arduino Pro Mini is a template and does not include specific functionality. It is expected that the user will add the necessary code to interact with the NRF24L01 module and the Humidity Sensor YL-69.