for that you will need a few essential components like dc motors
you can buy Raspberry Pi POE online from Robocraze at the comfort of your homes
And you also can control the speed of the stepper rotate by the frequency of the pulse
220V 5000W SCR Voltage Regulator
The Official Raspberry Pi 4 Metal Aluminum Case with Dual Cooling Fans (Black) is available at Robocraze starting from ₹599
Steel Float Switch Best Arduino for Starter in Robotics for that you will needSteel Float Switch This is a stainless steel float switch,contains no mercury. Light weight and simple working principle, high reliability. Used to sense the level of liquid within a tank, the switch may activate a pump,an indicator,an alarm,or other device. Simple structure,easy installation liquid level controller. Versatility means that it can be installed either at the top or base of your tank, depending on whether you wish to detect the water's