# Fifth Lichuang Electronic Design Competition# Two-degree-of-freedom turret based on Bluetooth

Note: * is required.

[Please fill in during the registration stage↓]   1. Self/team introduction Electronic production enthusiasts with many years of experience in software and hardware design and production.   2. Briefly introduce the project using an android phone to control the turret design through Bluetooth. The turret can move in both horizontal and vertical directions, and requires manual control of the shooting direction to fire. [Please fill in during the competition stage↓]   1. Describe the project details. The three servos control the horizontal rotation of the turret, the vertical rotation, and the propelling device for bullet launch. The horizontal rotation angle is 0-180 degrees, and the vertical rotation angle is 65 to 180 degrees. The buttons on the mobile app control the servo to rotate up, down, left and right at a speed of 10 degrees per second through Bluetooth. After rotating to the designated position, you can fire bullets at the target through the shooting button on the app. The front end of the bullet launching device is two DC motors. When launching, the motors need to rotate first. After receiving the firing command, the servo drives the bullet to the firing port, and the bullet is fired through the middle of the two DC motors.   2. Describe the challenges faced by the project and the problems solved. Three servos and two DC motors are used in the project, which requires high power supply. When using one power supply to power all devices at the same time, the switch of the DC motor will affect the power supply of the arduino nano and the servo. Therefore, a separate DC-DC module is used in the project to power the DC motor. The choice of Bluetooth module is also very important. Currently, Bluetooth modules include BLE module and SPP module. For simple serial port transparent transmission, only the SPP module is needed. If you use the BLE module, you need to do secondary development based on the BLE protocol. * 3. Describe the key points involved in the hardware and software parts of the project. The circuit connection between the Bluetooth module and the arduino nano: Bluetooth module nano RXD TXD TXD RXD GND GND VCC 5V The circuit connection between the servo and DC motor and the arduino nano: Vertical direction servo signal The cable is connected to nano D11. The horizontal direction servo signal cable is connected to nano D10. The shooting servo signal cable is connected to nano D9. Android and NANO communicate through the Bluetooth serial port. The instructions are as follows: if(ch == 'u') { tile_up(); //Vertical Rudder servo turns up 1 degree} else if(ch == 'd') { tile_down();//Vertical servo turns down 1 degree} else if(ch == 'l') { pan_left(); // The horizontal steering gear turns 1 degree to the left} else if(ch == 'r') { pan_right(); //The horizontal steering gear turns 1 degree to the right} else if(ch == 's') { shoot(); //shooting} else if(ch == 'm') { motor_on(); //DC motor is powered on} else if(ch == 'o') { motor_off(); //DC motor is powered off} Servo The speed of rotation is determined by the frequency of instructions sent by android. Currently, the android program sends instructions every 100ms. The shooting function needs to judge the current DC motor status. Shooting can only be performed when the motor is powered on, otherwise the servo will be stuck and burned.

The Android program uses its own Bluetooth library program to realize the function of scanning Bluetooth devices and displaying the device list. The device name in the Bluetooth list is bt04-A. Pairing is required when connecting for the first time, and the password is 1234. After connecting to the Bluetooth device, you will enter the control interface, and the up, down, left, and right steering wheel buttons realize long-press continuous control. Other control buttons are click controls.

< br> * 4. Project material list shows Arduino Nano X 1 MG90S servo X 3 L298N motor module X 1 130 DC motor X 2 MP1584EN DC-DC module X 1

  5. Upload project pictures 5.1. Print the contest logo picture on the PCB. If not, you will be deemed to have given up the competition.           5.2. Other pictures of the project. Bluetooth pairing APP interface    6. Demonstrate your project and record it as a video for upload. 6.1. Upload the video to the official website of the competition. 6.2, Station B. Video title and link The fifth Lichuang Electronic Design Competition: "Bluetooth-based two-degree-of-freedom turret" project - self-introduction https://www.bilibili.com/video/BV1hZ4y1N72S/ The fifth Lichuang Electronic Design Competition: " "Two Degrees of Freedom Turret Based on Bluetooth" Project - Project Introduction https://www.bilibili.com/video/BV1YK411P7ix/ The 5th Lichuang Electronic Design Competition: "Two Degrees of Freedom Turret Based on Bluetooth" Project - Function Demonstration https: //www.bilibili.com/video/BV12v411v7PZ/ < br> < br>   7. Whether it is released to the public for the first time. 7.1. If the project has been published or won an award before, please explain. 7.2. If the project is optimized on the original basis, please explain the optimization. Part   8. Open source documentation* 9. References

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