To parts are still missing:
Battery plus some voltage converters. You can use a USB-Powerbank für die 5V supply (Raspberry Pi2, Motor Voltage). And solder a small 5V To 3.3V LDO for the Motor Controller VCC and the IMU (it is not recommended to use the Raspberrys 3.3V output for externel use). You need the 3.3V because the I/O system of the Pi work with 3.3V.
Now you can Connect the IMU to the SPI Pins of the PI, if you IMU breakeout board only have I2C so you have to connect to the I2C bus of you PI.
now you connect the motors driver enable pins to the soft PWM Pins of the Pi. The Dir pin to other pi ins. wire the motor pins with the motor and you finished wire up.
then you sandwich the pi between the MoveBase and the Laser Sensor, put the camera in front and you are done with hardware.
an recommended Extension is to add motor encoders and an arduino (3.3V) or µC(3.3V). then you should connect the encoders and the motor driver to the arduino and the #arduino to the pi. An Arduino have a faster IO system so you can have a faster motor control loop, an Arduino is more deterministic then the PI, so you control jitter is much smaller. You load of Low Level Computation to the Arduino. There are Special Arduino libraries from ros to communicate.
Hello mam, I am working on a SLAM robot, i dont have any idea of where to start. I have arduino for navigation and i am using rapberry pi and eai X2L lidar for mapping, can you please tell me how to start with the build. I have put ubuntu 16.04 with Kinetic ros. Can you please help me?