Hello,

I would suggest that you break down your whole project in to small logical segments and then ask specific queries. Else the options are very wide and we will not be getting to the end fast.

First the DC motor drive - how are you planning to drive it and what power is it going to be - voltage & amperes ;Are you going to build the drive yourself or use a readymade one ; This will help decide what kind of control signal that you need to generate.

The sensor - what type is it ? Encoder with quadrature output ? Tacho ? Variable reluctance probe or Proximity switch and segmented wheel ?

What RPM range 10-100? 0-1000? x-y?

What accuracy for the set RPM ? 1%? 2%? less than these ?

And when you say Closed loop, you will need some kind of a PID controller to close the loop - these can be built in a variety of ways.

And the above are just the starters - kindly note that the homework done before jumping into the project is well worth its time. And for all you know once the defenition is done, you will find that there is excatly a system in the market meeting your specs. So easy, UNLESS you want build and learn about a closed loop DC motor control. In which case you can come back here with specific and pointed queries.

Raghu