For my project to develop a segway with an 3 dof robotic arm . Which is to detect for an bottle to pick and place it. For segway using one ardunio, 3DOF robotic arm using one ardunio and for detecting the bottle and calculate the distance using raspberry pi 3B+ . When detect the bottle the segway start moving and will stop distance between bottle and segway is 25cm after the robotic arm will start to pick the bottle and hold it. When the robotic arm will hold after to detect the stop sign board then it will go and place the bottle. for my project i have to use dc motor and encoders.