Having to perform a repetitive task by hand becomes quite laborious after even a short amount of time, which is why automating these tasks is so commonly done. The YouTuber known as Easy HomeMade Projects wanted to create his own DIY assembly line that would take empty bottles at the start, fill them, screw on a cap, and then make them exit the process, all without any human intervention.
The microcontroller selected for this project was the ubiquitous Arduino Nano R3 due to its small size and ample number of GPIO pins. Due to the presence of moving parts, a couple of actuators were needed, including a stepper motor/driver module and two pumps. Information is displayed on a large 20x4 character LCD while the operator has access to a green start/stop button to begin or end the automated process.
Filling up bottles is accomplished by using a 12v water pump that, when powered on, draws up water into a tube and pushes it into a bottle. The timing for how long the pump is activated is determined by a delay value in the Arduino Nano's code.
After a bottle has been filled, it moves onto the second and final step of having a cap placed on top and screwed in to create a seal. The method by which this machine accomplishes the task is quite innovative, as it uses another 12v pump to push air into a cylinder with a plunger inside. Due to pneumatic principles, this causes a rotating rubber stopper to apply enough force on the cap to achieve a tight seal.
Bottles are moved through the various stages of the assembly line by traveling along a large central wheel that has two cutouts for bottles placed opposite each other. The end of the line even has a small quality control device that uses an infrared emitter/detector pair to ensure the cap has been placed correctly.