Shift Registers for DC Motors and Motion Sensors

Hi Everyone,

I am a newbee.. Currently want to control DC Motors on/off states based on activity from motion sensors.

I am thinking about buying a shift out register that will allow the digital output of the below schematic to reach the transister so that the DC motor can be powered on or off.

Also thinking to pull in analog sensor data via shift in register. So that the data reaches the microcontroller serially. Does this make sense?

Is there a specific shift in/out register I should be using for this application?

Well, okay, it is possible to use shift registers and multiplexers for more output and input pins.
But it is a lot easier to buy an Arduino Mega 2560 board.
For sensors, the I2C can be used to connect many digital sensors to an Arduino board.

How many analog sensors to you want to connect ? and how many digital outputs do you need ?
The Arduino Leonardo has 12 analog inputs.
The Arduino Uno has 18 digital outputs (14 digital pins minux RX and TX and 6 analog pins that are also digital pins).

There are also I/O expanders, modules with extra inputs and outputs.

And it is possible to use an Arduino as I/O expander.
For example an Arduino as Master and many Slave Arduino boards (for example Arduino Leonardo boards because of the spare hardware serial bus). Then you can control hundreds of motors.