Here’s a cool diy on a DAC circuit to control a DC motor with your PC over the internet using Visual Basic Winsock.
The circuit that I chose for this assignment is the motor project. The DAC circuit will be used to control the speed of a DC motor. This can be done by creating a Visual Basic program to interface with the motor and the PC. The input from the client will be in decimal form (0 – 255) and these digital sequences will be converted into binary codes (analog form) by using the DAC (digital to analog converter). The output voltage to the motor has a range of 0 and +5 volts. Since 5 volts will not be enough to run the motor, the system will be amplified using a Power Op-Amp circuit that can give us a higher output voltage so that the motor will have enough power to run. To be able to remotely controlling the motor, the winsock component, (the pc as the server, user as client), will be added in the VB program. Other motor related hardwares can also be controlled over the internet using the same setup e.g. a fan. From this fundametal knowledge, one can improve the control of other complicated machines or systems remotely. This can save time, less work and more secure in some cases.