Control Dc motor speed using 8051

[Bilal Sadiq]

Re: Control 12v Dc motor speed using 8051.

hi every one can some one help me please
i do not know how to connect 12V supply for my dc motor with 5v microcontroller 8051 ,,,i mean to say in hardware what should i do ???? should i use LM7812 or how ,,,,,please do help me ,,,,,what and how i manage to run a 12V dc motor with 8051 microcontroller,,,i know the theory(about L293D) but on hardware how can i get 12 V ???
please help me and especially guide me please
waiting for nice advices and help ...
thanks

 

[Jigar 4 Electronics]

Re: Control 12v Dc motor speed using 8051.

Dear Bilal,
L293D has a 12V input pin through which it will provide supply to the motors.
See the diagram, It has pin-1 ,9 as a enable pin which you have to connect with pin-16 which is Vcc (5V) to enable the respective input-output port of L293D.
and pin-8 is Vs for the supply of DC motors, connect 12V DC supply to Pin-8.
But one drawback L293D has, is it can't give more than 600 ma to your motors, you can use L298 for that which will allow you to provide upto 2A to your motors.

 

[Bilal Sadiq]

hi every one
i need urgent help
please
i am using 89c51 with IR led and phototransistor as receiver
the circuit works very well (without 8051) then when light(IR ) falls on phototransistor (LED connected to it remains OFF) means its resistance is decreases and (i hve connected 2N2222 to LED (at its collector)) when i connect its output to LM339 for (giving it to 8051) " ............................."
ACTUALLLY I WANT TO MAKE "WHEN SOME ONE CROSSES (INTERFERE THE PATH BETWEEN IR AND PHOTOTRANSISTOR) it will give this change (from LM339) to 8051 pin and increement by one .............
but i
AM UNABLE TO DO HOW TO READ THE DATA "FROM OPAMP TO 8051 TO START PROGRAM"
BY opamp output is " 1.76V"
and "5.56V" IS 1.76V creating problem..............please help me as soon as possible
i shall be very thankful to you .....
thanks