All-in-one desktop model car Bluetooth receiver

This project is an all-in-one desktop model car Bluetooth receiver. It is used to statically modify small scale model cars such as 1/35, 1/43, 1/50, 1/64, etc., or replace existing complex, redundant and expensive electronic equipment on similar models. This project can replace traditional receivers, ESCs and light controls, reducing size and cost.

The functions of this project are as follows: 1. Integrated 600ma brush ESC 2. Integrated 3.7v lithium battery charger 3. Integrated 10 groups of LED light control (linkage, programming) 4. Integrated Bluetooth reception 5. Integrated digital transmission

The ESC uses FM116B, which is a mature H-bridge motor driver chip that is widely used in steering gears and helicopter tail drive circuits. This is also the smallest H-bridge driver I can find currently. It uses SOT23-6 and the maximum current is 550ma.

Through the IN1 and IN2 PWM signal input, four different modes of switching and stepless speed adjustment functions can be realized.

Integrated 1S lithium battery charging, set the charging current to 300mA, the measured heat is relatively large, more than 60℃, the design circuit needs to be well dissipated.

The servo drive needs to output fixed pulses. It is necessary to generate a PWM wave with a 20ms (50Hz) reference and an adjustable duty cycle. One degree of duty cycle = 1 / 90 * angle + 0.5.The board is ready and the size is compared with the power module. Front, back, install the car and take a look . From top to bottom are the light control test board, coreless motor, servo, and 3.7V battery (the micro one hasn’t arrived yet, so let’s experiment with the larger one first). The current logic is that the steering and accelerator each occupy one channel, with stepless speed regulation; the turn signal is linked to the steering channel; the brake light is linked to the reverse channel; and the headlights occupy a separate channel. This board has a return function, and currently it refers to the development of a voltage return function. At present, the interface of the mobile APP has limited time and has not been carefully optimized. It is in a usable state and will not be released for the time being. It will be released after optimization. There are comments in the Bluetooth communication protocol source code, you can modify it yourself.

In summary,         this board can meet the expected functions and achieve the expected goals. It is more suitable as a learning board. However, the project still needs polishing in the later stage. The main optimization work in the later stage is: 1. Improve the motor control strategy to achieve more delicate control; 2. Improve the APP; 3. Optimize the PCB to solve the charging heating problem. Finally, the HK32 microcontroller is used in this project, which has good compatibility with STM32 and is a better choice.