In the project design, two microcontrollers modeled PIC16F877A are used. Cascade microcontroller mechanism used in the design. Microcontroller 1 located at the racing car and microcontroller 2 embedded in user’s remote controller. The speed of the stepper motor detected by microcontroller 1 and the speed calculated referring to the speed equation obtained. The speed information is sent to the microcontroller 2 via cascade PIC. Microcontroller 2 receives the signal and displays the speed in the LCD screen. At the user’s remote controller, there is motor speed control mechanism. The speed controlled by potentiometer. Large value resistance will produce low speed while small value resistance produces high speed. The speed control information will send from the potentiometer to microcontroller 2. Microcontroller 2 detects the speed and sends the data to microcontroller 1. Speed of the stepper motor will be controlled by microcontroller 1. The speed control mechanism functions as the test board of the stepper motor. Basically, there is not much circuitry in our design. Main part in our design is the PIC programming. Most of the mechanisms are controlled by the PIC. There is also, motor driver to drive the stepper motor. The motor driver used is, SD02B from Cytron Technology. In the motor driver itself, contain a PIC. This PIC is used to control the UART (Universal Asynchronous Receiver Transmitter). UART is a piece of hardware that translates data between parallel and serial forms. Both cars contain the same circuitry mechanism and both unipolar and bipolar motor are using the same motor driver. PCB board was used to design the circuit. The racing car and remote controller is connected by 3m length of wires.
Our final product
The first version of our educational kit for stepper motor only can move forward and backward because we are using one stepper motor due budget limiting. The video above shown that the stepper motor has high torque when at low speed. This is one of the advantage of stepper motor.
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