DIY Automatic Juice Mixing Machine : Theory

In Thailand, approximately 200,000 people (March 2019) are visually impaired, including color-blindness, blurred vision, blindness, and etc. And, this number only includes people who has a registered disability; we would never know how many more there are. That is why I decided to make a machine to help them live a better, happier life.

Drinking water is more important than eating food; humans wouldn’t survive more than 3 days without drinking water. So, I made this machine that can mix drinks together automatically.

These are some examples of drinks that a blind person could find difficult because it uses a lot of ingredients. If they have a machine to help them mix it, they will have a variety of drinks to choose from.

How does the machine work?

A peristaltic pump is a type of pump for liquids used in hospitals in infusion systems. There are rollers inside the pump which will squeeze the silicone tube and create pressure, thus moving the liquid.

Because all of the ingredients used are liquids, this type of pump is suitable for this project. My machine will use three peristaltic pump for three ingredients which may include condensed milk, flavored syrup, and water.

The load cell

A load cell is a sensor used to measure weight which is typically found in a scale. For this project, using a scale to measure the ingredients’ weight is much more precise that timing their release. Therefore, if I want to mix a drink with precise ratios, it is crucial for the machine to have this device.

Closed loop control

Closed-loop systems are designed to automatically maintain the desired output condition by comparing it with the actual condition.

Closed loop control system diagram

Design

I designed the machine in fusion 360. The machine’s dimensions are 25 x 35cm and will be made from 3 mm thick acrylic sheets cut with a laser cutter and assembled like figure above. The machine will have an LCD display to show the information, a rotary encoder as an input device, and a load cell connected to a plate for feedback weight to the controller. There will be three peristaltic pumps located at the bottom inside of the machine. The back will have a hinge for easy access to the liquid containers. The entire system will be powered by a 12V 5Amps power supply. The machine is still in the making.

The next blog will be about how I made this juice mixer and testing it out.

https://medium.com/@panothai.pornprinya/diy-automatic-juice-mixing-machine-how-to-make-dc12c0289011