Dilshan R Jayakody’s Web Log

While designing some mechanical projects we often have need for easy to build motor speed controllers. Thanks to the SGS-THOMSON Microelectronic’s TDA7274, now we have easy to build, low voltage D.C motor speed controller. TDA7274 provides wide operating voltage range from 1.8V to 6V and in this project we use it to drive small CD-ROM ejection motors. In this project we design entire speed controller with 39.3mm × 28.9mm PCB. While at the prototyping we test this system with 5V power source and successfully control several CD-ROM ejection motors, cassette motors and toy D.C motors. You can obtain all the circuit diagrams, PCB patterns and other information of low voltage motor speed controller from google drive .

In this project we design 2 channel D.C motor controller with pulse width modulation (PWM) based speed and direction control. This module is mainly design to drive 14.4V to 18V electric D.C motors. This motor controller is design to work with 18V - 1.5A D.C power source and it can be directly interface with general microprocessor / microcontroller system (without using any voltage level shifters). While at the prototyping stages we successfully couple this module with several NIDEC D.C fans and blowers which include D1751M24B7AP, E1331K12B7AZ-00, DME37KA, CF24DM506, etc. Control interface for this module is easy to use and at the designing stages we interface it with PIC16F887 and Atmega64 MCUs. Control interface of this module is consisting with 3 inputs (please refer the J3 in the circuit diagram) and using these inputs user may be able to select the motor, apply the brakes and also change the rotational directions of the motor(s). When constructing the circuit it is recommend