KOS Developer's Portal

Overview

Introduction

In this set of tutorials we will:

Define a dispenser that we’ll work with in our ongoing KOS application tutorials (this page)
Write Java code that contains a circuit board and pumps
Test this new code by setting a breakpoint and viewing program values

Preliminaries

You should have completed the Hello World tutorial and have it ready build upon.

Overview

We are going to write Java code for our imaginary dispenser. It has a single display where the customer chooses his/her desired drink, a button that allows pouring of the beverage, and a single nozzle where it is dispensed. It could look something like this:

Figure 1. Small tabletop dispenser

Dispenser block diagram

We are going to keep its beverage list simple: the customer can choose from Coke, Diet Coke, Orange Soda, Grape Soda, and water.

The dispenser has a single-board computer, a nozzle, plain and carbonated water sources, and the four syrups. The following diagram illustrates the dispenser.

Figure 2. Block diagram of our demo dispenser

The hardware includes:

Six valves, one for each ingredient
One SBC (single-board computer) that controls each valve (on or off)
One nozzle for mixing and dispensing the ingredients, making the beverage
All of these are contained inside an assembly

Software components diagram

Here’s a sneak peek at the software components we’ll use that mimick the actual dispenser hardware:

Figure 3. Software components

We’ll have one Assembly that contains one Board, one Nozzle, and six Holder objects. A Holder represents how the ingredient connects to the dispenser. Each Holder connects to a single Pump, which controls the flow of each ingredient.

Valve vs. Pump

A valve is a special case of a pump. A valve has a simple on/off mechanism and a fixed flow rate. A pump controls and monitors the actual flow rate. The corresponding class in KOS is named Pump, so that’s the terminology we’ll use.

Multiple hardware components

In our example we have a single board and one nozzle. However, in many dispensers the assembly contains multiple boards and/or multiple nozzles. In addition, a holder can attach an ingredient to multiple pumps. KOS supports these variations and more. These simplifications are made to reduce the complexity of this first demo dispenser example.

What’s Next

In this and succeeding tutorials, we’ll write a KOS application that controls the computer, which then delivers the ingredients in the desired ratios to the nozzle, providing the customer with a cold refreshment!

On the next page, we’ll write some code to control some of these physical entities we’ve defined.

Overview

Introduction

Overview

Dispenser block diagram

Software components diagram

What’s Next

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