Introduction: How to Hack RC Car Receiver Via 2.4 GHz NRF24L01 Arduino Part 2 Rx+Servo+ESC

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This is the continued instruction of "How to Hack RC Car Transmitter via 2.4 GHz nRF24L01 Arduino part1 Tx"

The prerequisite instruction have introduced how to hack RC car Transmitter by using nRF24L01 module for Arduino Nano.

In this session we will build 2.4 GHz. receiver installed on a RC prototype car that has a Steering servo and Electronic speed control(ESC).

Thank to arduino-info.wikispaces.com , github.com/maniacbug/RF24 for RF24 library and other nRF24L01 module information.

You can purchase electronic parts from Aliexpress, Banggod,Ebay,etc.

Project more : http://hobbywitch666.blogspot.com

Step 1: Materials & Tools

Materials

1. 1 - Arduino controller - Nano

2. 1 - NRF24L01 module

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

4. 4 - LED 3 mm.(Option for car decoration)

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

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. 1 - Relay HRS1H-S-DC3V(Option for dumper driving )

12. 1 - Metal gear servo size 90 g.(Option)(It will be needed when RC car use steering motor drive)

13. 1 - ESC 30A for car with reverse function

14. Dupont wires.

15. Female pin header

16. Dupont Jumper Cable Housing Male Pin Connector

17. Dupont Jumper Cable Housing Female Pin Connector

18. Male JST Battery Pigtail

19. Female JST Battery Pigtail

20. JR Servo Lead Male extension cord(For servo and ESC connection)

21. Heat shrink tube 1.5 - 10 mm.

22. PCB - DIY circuit board

23. Velcro tape

24. Battery Lipo 7.4 V. 1000 mAh

25. 1 - Any RC car (Front Steering wheel + Rear wheel Drive)

Tools
1. Soldering gun.

2. Soldering wire.

3. Soldering paste.

4. Screw driver.

5. Plier.

6. Hot glue gun.

7. Epoxy glue.

Step 2: Electronic Parts Installation & DIY PCB

Steering Servo installation(Optional for Toy grade RC car)

Toy grade RC cars use steering motor drive.First ,it needs to modify steering housing to install Metal gear servo and fixed by hard epoxy.

Remove existing electronic board an other unnecessary devices.

Make DIY PCB

Build DIY PCB according to circuit diagram.

Arduino Nano pin No :

D3 - Steering servo signal(Use JR male plug)(There are three wires- Sig , Vcc , GND - Yellow , Red , Black)

D4 - Relay 3V. - Dumping motor(Option)

D6 - Electronic speed control(ESC)(Use JR male plug) - Driving Motor

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 - 10

SCK - 13

MO - 11

MI - 12

IRQ - 2

*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.

Steering servo

Connect servo's JR female plug to :

Signal(Yellow) - Nano D3

Vcc(Red) - 5V.supply

GND(Black) - Ground

Electronic Speed Control (ESC)

Connect ESC's JR female plug to :

Signal(Yellow) - Nano D6
Vcc(Red) - 5V.supply

GND(Black) - Ground

Power JST male plug connect to Lipo Battery .

Relay 3V.(Optional)

Connection Pin :

2 - 5V.supply

3 - Ground

4 - Nano D4

5 - Dumper motor terminal(Another motor terminal connect to Ground)

Decoration light(Optional)

1. Install LED lights at front and tail. Fixed by hot glue.

2. Wire LED positive poles parallel to supply 5V.

3. Wire LED negative poles serial to Resistor 1 kOhm. - Ground.

*Before connecting main supply , 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)

Step 3: Software Download & Upload to Receiver

Arduino sketch and Library :

1.Down load attached sketch file .ino and download library zip file for nRF24L01 module from https://github.com/maniacbug/RF24/downloads

2.Add library zip file to Arduino software.(After added 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 and nRF24L01 modules for pairing)

4.After matching the frequency ,we can upload Rx sketch to Receiver.(If you have problem,go to visit website https://arduino-info.wikispaces.com/Nrf24L01-2.4G.... for more information)

If communication complete ,serial monitor will show data as video clip.If not,go back to check hardware installation.

The received data will be scale back 10 times to get actual data.The Steering code between 150 - 910 and ESC code between 170 - 900 will be mapped to 0 - 180 and write value on servo command.To stabilize neutral position,we need if command to filter exact value for servo otherwise it will have jittering problem.The neutral value stay around 89 - 95 depend on each ESC brand , it should be calibrated and update the sketch.

Test playing RC car with transmitter a period to run in.

Good luck.

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