The instruction "How to build 8 Channel Transmitter nrf24l01 Arduino" introduce how to make 8 channel transmitter from 4 channel RC plane.All existing electronic boards had been taken off ,remaining 4 potentiometers of each control channels would be used after and adding new 4 potentiometers for more 4 control channels.

The rebuilt transmitter would be operated by Arduino controller.The new design program should be applied to remote control various devices via nrf24l01 radio module such as robotic arm,multi servoes,rc planes,rc tanks,rc cars,rc boats ,etc.

Step 1: Materials & Tools

Materials

1. 1 - Arduino controller - Nano

2. 1 - NRF24L01+PA module with SMA anttenna

3. 1 - Socket adapter for NRF24L01(For protect & stabilize NRF24L01 module)

4. 2 - LED 4 mm.(green and red)

5. 2 - Resistor 1 kOhm. 1/4 watt.(Option)

6. 1 - Capacitor 0.1 microF /50V.

7. 1 - Capacitor 1 microF /50V.

8. 1 - Capacitor 100 microF /50V.

9. 1 - Diode 1N4001

10. 1 - 7805 IC Regulator 5V.

11. Dupont wires.

12. Female pin header

13. Dupont Jumper Cable Housing Male Pin Connector

14. Dupont Jumper Cable Housing Female Pin Connector

15. Male JST Battery Pigtail

16. Heat shrink tube 1.5 - 10 mm.

17. Velcro tape

18. 1 - PCB.DIY. circuit board

19. Battery Lipo 7.4 V. 1000 mAh (2 cells)

20. Four channel RC transmitter

21. 4 - B10K potentiometers

22. Electrical 26 AWG wires

Tools
1. Soldering gun.

2. Soldering wire.

3. Soldering paste.

4. Screw driver.

5. Plier.

6. Hot glue gun.

7. Epoxy glue.

8. Two sides glue tape.

9. Plastic cutter.

Step 2: Body Modification , Electronic Parts Installation & DIY PCB

Body modification & DIY PCB

1. Open transmitter body up,remove old existing PCB ,leave 4 potentiometers Aileron,Elevator,Throttle,Rudder.

2. Make DIY PCB according to circuit diagram.(See pin connection below)

*Soldering all devices carefully ,use enough large wire.Making good ground.

3. Drill transmitter body for installing 4 more potentiometers.

4. Cut off plastic body to open a hole for Nano USB.

5. Paste Velcro tape at the transmitter back for battery attachment.

6. Install DIY PCB and NRF24L01 module on transmitter body by hot glue.

7. Connection wiring between DIY PCB , Potentiometers , main switch and battery terminal.

8. Assemble transmitter body back.

*Before connecting battery,check out to find short circuit points on DIY PCB.Otherwise it can smoke and burn everything. (Be careful of Lipo battery , it's high current supply , short contact will spark fire)

Arduino Nano Connection pin No :

A0 - Auxillary4 potentiometer

A1 - Aileron potentiometer

A2 - Elevator potentiometer

A3 - Throttle potentiometer

A4 - Rudder potentiometer

A5 - Auxillary1 potentiometer

A6 - Auxillary2 potentiometer

A7 - Auxillary3 potentiometer

D3 - Throttle hold LED

D7 - Throttle hold switch

nRF24L01 module Socket adaptor to Arduino Nano pin No :

Vcc - 5 V. supply (Do not connect 5V. direct to nRF24L01 module,it's supplied only 3.3V.)

GND - GND

CE - 9

CSN - D10

SCK - D13

MO - D11

MI - D12

IRQ - D2

*If you have communication problem,you can change connection from pin 13,11,12 to pin SCK,MOSI,MISO of Nano programming pins.

*It's necessary to add 0.1 microF to nRF24L01 module pin Vcc/GND because the module needs stable current and voltage. Also solder a small wire at the antenna to increase control range.

Step 3: Software Installation

1.Down load nRF24L01 module library zip file from https://github.com/maniacbug/RF24/downloads.

2.Add library zip file to Arduino IDE.(After finish addition, you will see new library RF24-master in Examples menu.)

3.Before using new nRF24L01 modules,we shall burn the modules by uploading default sketch pingpair and GettingStarted for tuning up frequency otherwise it will has uncommunication problem. (Use another Arduino Nano/UNO and nRF24L01 modules for pairing)

4.After matching the frequency ,we can upload Tx code sketch from GitHub to rebuilt transmitter.