DIY RC Transmitter & Receiver (Arduino + nRF24L01+ → PPM)

Overview

This project implements a simple, low-cost RC system using two Arduino boards and nRF24L01+ modules. The transmitter reads two joysticks, two potentiometers, and two toggle switches, then sends their states wirelessly. The receiver outputs a standard PPM signal for use with most flight controllers.

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Hardware Required

Transmitter:

• Arduino Nano/Uno/Pro Mini
• nRF24L01+ module
• 2× 2-axis joysticks (potentiometer-based)
• 2× SPDT toggle switches
• 2× potentiometers (10k)
• 1× LED (optional, for toggle feedback)
• Wires, breadboard or perfboard, enclosure

Receiver:

• Arduino Nano/Uno/Pro Mini
• nRF24L01+ module
• 2× LEDs (optional, for toggle feedback)
• Connects to flight controller via PPM (single wire)

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Pin Connections

Transmitter

• nRF24L01+:

  • VCC → 3.3V (not 5V!)
  • GND → GND
  • CE → D9
  • CSN → D10
  • SCK → D13
  • MOSI→ D11
  • MISO→ D12

• Joystick 1: X → A0, Y → A1, SW → D2

• Joystick 2: X → A2, Y → A3, SW → D3

• Potentiometer 1: Wiper → A4

• Potentiometer 2: Wiper → A5

• Toggle 1: A → D4, B → D5, middle pin to GND

• Toggle 2: A → D6, B → D7, middle pin to GND

• LED1: D8

Receiver

• nRF24L01+:

  • Same as transmitter

• PPM output: D4 (connect to FC PPM input)

• LED1: D3, LED2: D2 (optional, for toggle feedback)

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How to Build

1. Wire up the transmitter and receiver as described above.
2. Flash drone_transmitter.ino to the transmitter Arduino.
3. Flash drone_receiver_ppm.ino to the receiver Arduino.
4. Power both boards (ensure nRF24L01+ gets a stable 3.3V with a 10–47µF capacitor across VCC/GND).
5. Connect the receiver's PPM output (D4) to your flight controller's PPM input.
6. Test: Move sticks and switches on the transmitter; the receiver outputs a PPM stream reflecting all 10 channels.

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Features

• 10 channels: 4 axes, 2 buttons, 2 pots, 2 toggles
• Failsafe: If signal lost for 1s, all channels set to 1000us
• PPM output: Standard 10-channel PPM
• LEDs indicate toggle switch states

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Notes

• The code uses the RF24 Arduino library.
• PPM output is compatible with most flight controllers (Betaflight, iNav, ArduPilot, etc.). Tested with iNav and Betaflight.
• No OLED or telemetry in this version as Arduino memory is limited.
• For best range, use nRF24L01+ PA/LNA modules and keep antennas clear.

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Troubleshooting

• If the receiver does not respond, check wiring and power to nRF24L01+ modules.
• Add a large capacitor (10–47µF) close to the nRF24L01+ VCC/GND.
• If PPM is not detected, verify the output pin and FC configuration.

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