Background of the project
Looking at the timetable, the open source official has not released a project for a year! After much deliberation (under the coercion of Sister Ju), I finally decided to make a work with a sea, land and air theme.
It is not a tank QAQ. Although it looks like a tank, it cannot fight on land and can only swim on water.
After three version iterations and model modifications, I confidently took it into the water, however...
It has done all the things of capsizing, drowning, and spinning in circles. If I hadn't fished it out quickly, I would have stayed with the fish in the lake for the rest of its life (it sounds quite romantic).
Although there are still many functions that have not been perfected, they are already movable, and the remaining functions need to be slowly iterated after free time.
Introduction to function parameters
- Power input: DC5-12V.
- High-power RZ7899 motor driver chip, maximum current 6A.
- Has emergency stop function.
- Overheating protection.
- Four-way boat lights.
- Long-distance remote control, up to 2000M supported.
- Two servo interfaces are reserved for later expansion of functions.
- Comes with matching 3D shell files for easy design of customized shells.
Circuit description
3.1 Power input circuit
Because the driving voltage of the boat motor needs to be directly between 6V and 9V, while the voltage required by our microcontroller is 3.3V, and the voltage of the remote control module needs 5V, it is necessary to carry out a voltage reduction design for the 7.4 battery. The 7.4V power input flows into the LD117 and XC6201P332MR and is converted into 5V and 3.3V voltages for use by the microcontroller and other modules. An additional 6P Type-C interface is reserved at the input end to facilitate power supply debugging.
Motor drive circuit
The motor uses a medium-to-high-speed 7-9V brushed waterproof motor. The motor is DC. The control uses PWM for speed control. The farther the remote control joystick is moved forward, the faster the speed.
The circuit uses the RZ7899 motor-specific drive chip, which is the same model as the Lichuang car. RZ7899 is a DC bidirectional motor drive circuit. It is suitable for motor drives of toys, automatic valve motor drives, electromagnetic door lock drives, etc. It has two logic input terminals to control the motor forward, backward and braking. This circuit has good anti-interference, small standby current, and low output internal resistance. At the same time, it also has a built-in diode that can release the reverse impact current of inductive loads. It has a wide operating voltage range of 3.0V~25V, has emergency stop function, overheat protection function, overcurrent embedded current and short circuit protection functions.
Microcontroller minimum system
The control chip uses the STM32F103C8T6 chip. After all functions are completed, subsequent updates will be modified to become a domestic MCU or a cheaper MCU.
Ship light control circuit
The boat lights use an 8mmV ultra-bright direct LED lamp bead, which supports a maximum voltage of 5V, so there is no need to build a separate drive circuit. You only need to leave the control interface, and the microcontroller uses io and uses low-level drive.
remote control reception
The remote control reception uses the LORA wireless serial port module. The interface is multiplexed with the SMT32 serial port download circuit. If you need to use the serial port for programming, you need to modify the circuit. It is recommended to use 5V power supply, which is more stable and can support up to 3000M. Before use, you need Make pairing settings with the transmitter. A version of 2.4G remote control will be iterated later.
remote control
The remote control is modified from Jixiaoxin's 2.4g remote control. The design drawing has been put together with the control board project. Click Edit in the upper right corner to open it to see it.
Precautions!
- After the boat is assembled, it needs to be balanced
- The remote control needs to be paired before use
- After the shell is assembled, it needs to be aligned and caulked and waterproofed.
Summarize
Because I have been busy recently, the boat design has been hasty and the functions are a bit off. I will iterate the version later when I have time. Finally, I would like to thank several of our friends who participated in the design and debugging. We look forward to a more complete boat design in the future.
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