Robot arm CS-113 18F4550 PIC USB PC controller

Full circuit schematic to operate robot arm CS-113 with 18F4550 PIC and Toshiba TD62064AP darlington drivers. USB PC communication control.

Description

Robot arm CS-113 equipped with 18F4550 microcontroller and USB PC communication to control the arm. The full schematic circuit, which includes the stepper motors connections with the microcontroller, LEDs connections, USB connection, push buttons and voltage source is completely described. The microcontroller is programmed with USB protocol and it is capable of receiving a string of characters which specify the movements the robot arm must perform. This string of characters is validated by the microcontroller. Through a couple of LEDs the microcontroller informs if a string received was incorrect and if the arm is moving. There are also two push buttons connected to the microcontroller, if one of them is pushed the arm executes a test, which is a series of pre-programmed combinations of movements.

Details

With respect to the USB protocol, CDC class is used (Communications Device Class) to the communication between the Host (PC) and the device (microcontroller). In order to stablish communication through the PC, a desktop application must be developed; to avoid this and simplified the work, a virtual serial port driver and a terminal that binds to said virtual port is used to send the string of characters to the microcontroller. Although the string is sent via serial communication the virtual driver converts this to USB protocol, which is the one physically used. The terminal used is putty.

The code is well organized in several files and functions. Each stepper motor has separate function. Although all the material is in spanish it is really intuitive.

The compiler version used is: xc8-v1.34. Newer version may not function with the USB files.

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