# M I C R O C H A L L E N G E · I I

June Bascaran · Sami Piercy · Josephine Bourghardt

For this Micro Challenge we have been working with creating tools for part of a Beach Cleaning Kit.

### C O N C E P T

For the past months we have been volunteering with the organisation Clean Beach Intiative. They organise weekly beach cleaning sessions every Staurday at Barceloneta. Through this experience we realised the amount of micro plastics, and the difficulty to collect them with the tools provided. We have therfor been experimenting and testing different nets and tools to collect these small pieces more efficiently.

Everything that is collected during the session is later sorted and weighed to be recycled. All the very small pieces take too long to sort from all the bags and are therefor thrown in the normal trash.

We want to create tools to collect and sort these smaller pieces. We would also like to be able to weigh them in the same way that the other waste is to communicate the amount of microplastics that are collected during this one hour session.

### P R O P O S E

- Portable & Stackable collecting and sorting trays
- Handheld microplastic siv
- Sorting divider for collection bag

### B R A I N S T O R M

We started brainstorming ideas of how to collect and visualise the amount of microplastics collected. The tools can then be tested next time we go for the organised beach cleaning with Clean Beach Initiative Barcelona.



### C N C : S A N D · S I E V E

To be able to test different net sizes and textures while at the beach collecting microplastics from the sand we created a handheld sieve where the net size and texture can be changed. It was created by CNC cutting a back part and laser cutting the front. The shape is inspired by ping pong rackets, to be compact and easy to bring and store, yet give space to sieve and shake thorugh the sand.

I D E A T I O N · F O R M & S I Z E

P R O D U C T I O N

S T E P · 1
We drew the 3D model in Rhino in different variations to test size and form. We tested these parametres parallel with cutting simple pieces in cardboard to assure that the size would be appropriate to hold with one hand, that the length and that the width of the handle is good for a holding. We chose to proceed with a more square shaped model that has more space to sieve.


S T E P · 2
Thereafter the Rhino.3dm file is to be processed to CNC cut. Depending on the CNC macine used there are different ways to process the file. In this case we are using a ......

First choose all curves that will be cut (profiles) and carved(...) and Make 2d.

S T E P · 3
Choose which drill you want to use, where we in this case we used a 6mm downcut drill. We then set the parametres of speed and how much it will cut for every layer for the material used - 15 mm Plywood.

S T E P · 4
First add points around the curves that will be cut for marking the material to screw it tightly to the table. Second, choose the curves that will be 'carved' and set parametres for depth and if cutting inside or outside of the curve. Third choose curves within the form that will be profiled and set the parametres, here adding add ons so it keeps the material in place after being cut. Forth choose the curves that are the outlines of the form, here we set the same parametres for profiling and again adding add ons.

S T E P · 5
Test run the cutting path in the program to make sure it runs smoothly. We could here see that we could have problems with the sides being quite thin, where by cutting against the wood grain, there might be big splinters. As this is a prototype for testing it is not an issue, but for a good finish this would have to be considered in the design.

STEP · 5
To set up the CNC, first place the material and set your 'home' by moving the x & Y axis to the very point of the material. Then set the Z axis by using the magnet assigned to the machine.

S T E P · 6
Import the CNC files made and start with adding marks for the screws. When this is done, move the CNC away from the material and screw the material to the table in the marks that have been made.

Therafter start your file for ... and profiling. Stay with the machine until it is finished to make sure it cuts correctly and nothing goes wrong.


S T E P · 7
When finished, move the CNC machine away from the material. Use a vacuum or airpressure to blow away the sawdust from the cuts made and check so it has cut through all the way. In this case it had and we removed the material from the table and cleaned the machine.

S T E P · 8
The parts were a bit rough on the edges and needed some sanding to clean them off. Therafter the top part was laser cut.

S T E P · 9
To assemble, use the front lasercut part as a guide to cut the size of net that is preferred and cut around it. Place the cut out net into the bottom part and press it in place with the top. Right now the parts fit together and hold in place, if this form and tool works well when tested together with Clean Beach Initiative we will have to work on how tey will be attached with eachother.

### B A G : S O R T & S T O R E

- Cardboard sheet
- Reusable bag

We designed a simple divider to be used inside the bags for bigger items at the beach. Currently during the beach cleanup we fill the bags, and then separate them in the end. In having a divider, it would keep items more organized and help with the sorting process. It also keeps the bag balanced and easier to carry.

S T E P · 1
Design a simple flat pack divider in Rhino. Dimensions are fitting inside a standard reusable bag. With two slits, the two rectangles can be slotted together. We made one for four sections and one for six.


S T E P · 2
Cut out design in cardboard and slot them together. Here is the divider inside the bag with four sections.


### L A S E R C U T : S O R T & S T O R E

We made a series of boxes to contain the collected plastics, based on their size. The boxes are stackable and can be carried together or used separately. The base is used as a scale, where the collected material can be weighed. Each box has a different size mesh to sort 3 sizes of microplastics and waste from the beach. Together they display the collected amount of microplastics found at the beach, and with sorting allow possibility of using the plastics for another use.

- 3mm Acrylic
- 4mm Plywood
- 10mm Wood dowel
- 3 sizes of mesh
- 4 screws per box
- 4 nut bolts per box

S T E P · 1

We designed in Rhino the size, amount of boxes, and dimensions we wanted for our sorting boxes. We added keying features on the side so that the boxes could be easily carried with an inserted dowel rod.


S T E P · 2

With the help of an online box generator, we used MakerCase to make sure the sides would interlock. After we modified their drawing to have holes on the bottom instead of the sides.

Here is the website: https://en.makercase.com/#/basicbox

S T E P · 3

We laser cut three of the boxes in acrylic, and one in wood. The wood box also had a hole in the front to be able to see the LCD screen.

S T E P · 4

After assembling the acrylic and wood boxes, we attach the desired mesh. Each acrylic box has a wooden frame below it, trapping mesh inbetween the two layers. The wood frames can then be removed to replace or test different sizes of mesh.

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S T E P · 5

Next we connected the load cell to a piece of wood to create the scale. The load cell is drilled into a piece of wood and and a piece of acrylic on top. We used the negative cutouts of our box frames for these parts.

S T E P · 6

Last, we insert place all of the electronics into the wood box, attach the LCD screen, and secured the scale on top with screws from the bottom of the box.


E L E C T R O N I C S

The electrical components of this product consist of a load cell amplifier that allows measuring weight, a display, and an Arduino-compatible chip:

- HX711 Sensor
- OLED Display SSD1306 Screen
- Chip ESP32

S T E P S
To start up the electronic part of this product, a step-by-step process has been carried out to avoid errors and make the process easier.

1º **HX711 Sensor**

#include "HX711.h"  // include the library

HX711 scale;  // create an instance of the HX711 object

void setup() {
  Serial.begin(9600);  // initialize serial communication
  scale.begin(22, 23);  // initialize the scale with the pins connected to HX711
  scale.set_scale(-404.54);  // set the calibration factor to calculate weight in grams
  scale.tare();  // reset the scale to zero
}

void loop() {
  float weight = scale.get_units();  // get the weight in grams
  Serial.print("Weight: ");
  Serial.print(weight);
  Serial.println(" g");
  delay(1000);  // wait for 1 second before taking the next reading
}

Replace LOADCELL_DOUT_PIN and LOADCELL_SCK_PIN with the pins connected to HX711, and CALIBRATION_FACTOR with the calibration factor for your load cell. You can find the calibration factor by placing a known weight on the load cell and measuring the output. Then use the formula CALIBRATION_FACTOR = output / weight to calculate the calibration factor.

2º **OLED Display SSD1306 Screen**


#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
// The pins for I2C are defined by the Wire-library. 
// On an arduino UNO:       A4(SDA), A5(SCL)
// On an arduino MEGA 2560: 20(SDA), 21(SCL)
// On an arduino LEONARDO:   2(SDA),  3(SCL), ...
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define NUMFLAKES     10 // Number of snowflakes in the animation example

#define LOGO_HEIGHT   16
#define LOGO_WIDTH    16
static const unsigned char PROGMEM logo_bmp[] =
{ 0b00000000, 0b11000000,
  0b00000001, 0b11000000,
  0b00000001, 0b11000000,
  0b00000011, 0b11100000,
  0b11110011, 0b11100000,
  0b11111110, 0b11111000,
  0b01111110, 0b11111111,
  0b00110011, 0b10011111,
  0b00011111, 0b11111100,
  0b00001101, 0b01110000,
  0b00011011, 0b10100000,
  0b00111111, 0b11100000,
  0b00111111, 0b11110000,
  0b01111100, 0b11110000,
  0b01110000, 0b01110000,
  0b00000000, 0b00110000 };

void setup() {
  Serial.begin(9600);

3º **Connect everything**


#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "HX711.h"

#define OLED_WIDTH 128
#define OLED_HEIGHT 32
#define OLED_RESET -1

Adafruit_SSD1306 display(OLED_WIDTH, OLED_HEIGHT, &Wire, OLED_RESET);
HX711 scale;

void setup() {
  Wire.begin();
  Serial.begin(9600);
  scale.begin(4, 5);
  scale.set_scale(-410.9090);
  scale.tare();
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(2);
  display.setCursor(0, 0);
}

void loop() {
  float weight = scale.get_units();  // get the weight in grams
  Serial.print("Weight: ");
  Serial.print(weight);
  Serial.println(" g");
  display.clearDisplay();
  //display.setCursor(0, 0);
  //display.print("Weight: ");
  display.setCursor(25,10);
  display.print(weight);
  display.print(" g");
  display.display();
  delay(2000);  // wait for 1 second before taking the next reading
}

To connect everything in one, it is necessary to change the pins LOADCELL_DOUT_PIN and LOADCELL_SCK_PIN so that the communication between the HX711 sensor and the ESP32 chip is not I2D.

F L O W C H A R T

### R E S U L T S


## F U T U R E · D E V E L O P M E N T

We will bring these tools to the next Clean Beach Initiative to try them out together with the other volunteers. We can now quickly try different nets for different parts of the beach.

## C O N T R I B U T I O N S
We have worked together and collaboratively, sharing our knowledge and ideas. But our skills have been reflected in some moments of the project.

Sami - Background in Industrial Design: Skills in having a more technical product vision and knowledge in the use of 2D modeling tools and laser cut.

June - Background in Industrial Design Engineering: Skills in having a more technical product vision and knowledge in the use of Arduino and electronics.

Josephine - Background in Product-furniture design. 3D and 2D modeling skills, production and project vision.

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## R E F E R E N C E

https://www.euronews.com/green/2023/01/08/what-are-nurdles-and-how-are-they-devastating-the-environment

https://tienda.bricogeek.com/sensores-presion/1291-celula-de-carga-5kg-con-amplificador-hx711.html

https://www.youtube.com/watch?v=GrZz-ntRSAE&t=2s

https://www.taloselectronics.com/blogs/tutoriales/celda-de-carga-hx711

https://blog.florianuhlemann.de/arduino-oled-128x64-display-ebay-china/

https://openai.com/blog/chatgpt