Coin collector and register for vending machines

Introduction

A few years ago, developing a prototype of a product was expensive and difficult to produce with plastic injection. Today, with the advancement of industrial 3D printing, you can produce any product, test it and spend very little money. All thanks to the manufacture of parts with industrial 3D printing.

3D printing has transformed the way we create and customize parts for electronic projects, enabling the manufacture of complex components with precision and agility.

In this article, we explore how 3D printing was instrumental in the development of a coin collector designed for vending machines. The housing of this system, which houses a coin acceptor, an LCD display, and a control board, was entirely designed and manufactured using 3D modeling and 3D printing.

This approach not only ensured a perfect fit for the electronic components, but also enabled a custom, functional design that met the specific needs of the project.

In the context of technological evolution and the need for customized solutions, industrial 3D printing stands out as a powerful tool for engineers and those interested in building electronic prototypes who want quality and manufacturing speed.

Thanks to JLC3DP, you can print your parts for as little as $0.3 and obtain them with a quality and finish similar to parts manufactured in thermoplastic injection molds.

It was created with the support of JLC3DP. JLC3DP is the largest company in China in electronic board prototyping, machining and 3D printing. You can print industrial quality parts from $0.3. The price is very cheap and you will get parts with instructional quality that look like injection molded parts.

Now... Let get started!

3D Modeling and 3D Printing

The first step in product development or prototype is divided into two parts: designing the project in the 3D modeling tool and adapting the project to be manufactured using 3D printing based on fabrication rules of 3D printing processes.

3D Modeling Process

3D modeling is a very important step in the production process of any product. It is during the creation process that we carry out structural planning, select the appropriate material and perform all simulation tests to ensure that the parts are subsequently manufactured safely and with quality.

Below, we have the device presented with 3D modeling device.

The structure of the device consists of 4 general purpose buttons, an LCD display to present the information and the coin acceptor. On the back we have a power connector and an access drawer to collect the collected coins.

As mentioned earlier, 3D modeling for 3D printing of anything requires planning. One of the major planning points in this project was the organization of the user interface with the 20x4 LCD display, the buttons and the coin acceptor.

Planning the user interface is a very important step during the design phase. Observe the internal structure and see that each component is organized and easy to access so that it can be manipulated and facilitate connections between them. Below is the internal structure.

The panel housing structure is constructed to be separate from the main body. This facilitates assembly and connection between the various parts of the device. Below you can see the 3D structure in exploded view of the project.

This assembly analysis step is of fundamental importance during the 3D modeling process. It ensures that we can evaluate the assembly process and minimize the risk of possible errors during the 3D printing process.

This facilitates the part manufacturing process, reduces 3D modeling time for error correction and minimizes manufacturing costs due to 3D modeling errors. Carrying out these steps carefully allowed us to manufacture the structure without any errors, thanks to the testing and analysis tools of the structure in 3D modeling. Next, we will present the 3D printed structure.

3D Printing Device

From the 3D modeling we 3D print each part of the project. Below we present the result of the 3D printing.

The 3D modeling phase is fundamental as it allows us to analyze each structure and minimize design errors in 3D printing.

3D printing allows you to turn your idea into reality, and perform tests and assembly checks on the entire structure that was created in the virtual environment.

The structure of the electronic enclosure shown above took an average of 15 hours to print. Many users' biggest fear is making mistakes when printing large parts. However, with good 3D modeling and prior analysis of your design, these errors can be minimized. See the system working and counting the coins.

Any user can print parts on the 3D printer, even if you don't have a 3D printer at home.

With the advancement of 3D printing technology and the emergence of industrial 3D printers, the cost of manufacturing and materials has reduced significantly. Today, you can print parts that look similar to a part manufactured with injection molds using industrial 3D printing.

JLC3DP, a giant in the 3D printing sector in China, is increasingly making its 3D printing services cheaper. Today, there are more than 5 different technologies that allow you to print parts with polymers and steels and the cost starts at $0.3.

3D printing makes it possible to create enclosures that not only protect electronic components, but also ensure the ergonomics and aesthetics of the final product, increasing its appeal in the market.

The ability to customize every detail of the enclosure means that products can be tailored to meet specific customer needs, making them unique and differentiated from the competition.

Electronic structure result of the project with 3D printing

3D printing makes it possible to create enclosures that not only protect electronic components, but also ensure the ergonomics and aesthetics of the final product, increasing its appeal in the market.

The ability to customize every detail of the enclosure means that products can be tailored to meet specific customer needs, making them unique and differentiated from the competition.

Below we have the internal structure of the coin collector. As you can see, the system consists of an electronic coin acceptor, a 20x4 LCD display and a shield board for connecting all the cables to the Arduino UNO.

As you can see, all the components were properly fitted into the structure as planned in the 3D modeling phase and the result obtained was satisfactory.

There are several types of electronic fastening elements, such as: glue, threaded fittings and screw fastening.

You can turn your idea into reality with 3D printing! Get started now! Imagine turning that idea in your head into reality.

Using the electronic connections, we developed the code below. Its purpose is to read the coin acceptor pulses and display the value of the money count placed in the machine.

#include  <Arduino.h>
#include <Wire.h> //Biblioteca de Comunicacao I2C 
#include <LiquidCrystal_I2C.h> //Biblioteca I2C do LCD 16x2

LiquidCrystal_I2C lcd(0x27,20,4);  // Configurando o endereco do LCD 16x2 para 0x27

// variable use to measuer the intervals between impulses
int  time = 0;
// Number of impulses detected
int impulsCount=0;
// Sum of all the  coins inseted
float total_amount=0;

void setup() {
 pinMode(2, INPUT_PULLUP);
  Serial.begin(9600);
 // Interrupt connected  to PIN D2 executing IncomingImpuls function when signal goes from HIGH to LOW
  attachInterrupt(0,incomingImpuls, FALLING);
    lcd.init();                      //Inicializacao do LCD
  lcd.backlight();
    lcd.clear();

  lcd.setCursor(3,0);
  lcd.print("Coin collector");
  lcd.setCursor(0,2);
  lcd.print("Insert a coin:");
  lcd.setCursor(0,3);
  lcd.print("R$ ");
  lcd.setCursor(3,3); 
  lcd.print(total_amount);
   delay(2000);
}

void incomingImpuls()
{
  impulsCount=impulsCount+1;
  time=0;
}

void loop() {
  time=time+1;
 
  if (time>=30  and impulsCount==5){
    total_amount=total_amount+0.5;
    lcd.setCursor(0,3);
    lcd.print("                ");
    lcd.setCursor(0,3);
    lcd.print("R$ ");
    lcd.setCursor(3,3); 
    lcd.print(total_amount);
  Serial.print(" Total:");
  Serial.println(total_amount);
    impulsCount=0;
  }

   if (time>=30 and impulsCount==4){
    total_amount=total_amount+1;
    lcd.setCursor(0,3);
    lcd.print("                ");
    lcd.setCursor(0,3);
    lcd.print("R$ ");
    lcd.setCursor(3,3); 
    lcd.print(total_amount);
  Serial.print(" Total:");
  Serial.println(total_amount);
    impulsCount=0;
  }

  if(time>15 && (impulsCount<4||impulsCount>5))
  {
    impulsCount=0;
  }

  delay(15);
}

To ensure that each pulse is correctly identified and counted, we use the Arduino's external interrupt.

The next condition is used to detect that the user has inserted a 1 real coin. When a 1 real Brazilian coin is inserted, the system receives 4 pulses from the coin acceptor.

As you can see, the system correctly detects and calculates the value entered for each currency. From there we can expand to other applications and use it to create a product release system when the user inserts a certain amount of money.

Through 3D printing, it was possible to assemble the complete structure and create the prototype of a product solution for a future sales solution for the market.

You can start today and turn any idea that is in your head into reality, create innovative products and impact your customer with a professional visual presentation of a product with industrial 3D printing.

Conclusion and upcoming updates for this project

The next step for this project is to develop an electronic board with ESP32 and remove the Arduino. The goal of using ESP32 is to allow the device to have access to the internet and we can receive this data on a web server to obtain payment information and store this information in a database.

From this, we can expand the processing capabilities of the system and integrate it with other technologies

This coin donation box project, which can be evolved into a sales system, demonstrates the power of to be used in several applications of payment system. Thanks to the precision of 3D printing and the reliability of printed circuit boards, it was possible to create an innovative and efficient solution.

For those seeking quality and precision in their projects, we recommend the services of JLCPCB and JLC3DP. With years of experience and cutting-edge technology, these companies offer complete solutions for PCB manufacturing and 3D printing, ensuring that your ideas become reality with excellence and efficiency. Printed circuit boards can be manufactured starting at $2, and the price of 3D printing starts at $0.3, making these services accessible for all types of projects.

See the services of JLCPCB and JLC3DP and take your projects to the next level. Whether for prototypes or mass production, rely on the best to achieve outstanding results. Discover JLC3DP's services, make your 3D print and draw your own conclusions about the impressive print quality and surface finish of the process.