Created June 18, 2020

The push plate

By stepping on a plate and without using your hands you can control and use automatic doors, elevators and much more safe and easy.

Intermediate140

Things used in this project

Hardware components

Arduino Nano Every

Resistor 10k ohm

Relay (generic)

Switch Accessory, Spring

Needs to be 12 mm in diameter and about 11 mm in height.

9V battery (generic)

Resistor 220 ohm

Used to set the right brightness on the LCD display.

Single Turn Potentiometer- 10k ohms

Any type of trimpotentiometer will work as long as 10k.

Battery Holder, PP3 (9V) x 1

Any 9V battery holder will work. I used a bigger plastic one.

Hook Up Wire Kit, 22 AWG

Linear Regulator (7805)

5V 1A voltage regulator to power the circuit for the LCD.

Capacitor 22 pF

16 MHz Crystal

Capacitor 10 µF

Electrolytic Capacitor, 0.1 µF

Button SMD

SD-card reader/writer

General Purpose Transistor NPN

I used a BC547B.

Resistor 1k ohm

1N4007 – High Voltage, High Current Rated Diode

Most regular diodes schould work.

Machine Screw, M4

For mounting LCD display. Should be about 15 mm long.

M4 Nut

Two is used on each screw. One to act as a distance between LCD and box and the other to tighten down screw.

M4 Washer

Machine Screw, M2

Used to mount different components in the box.

M2 Washers

M2 Nut

Two nuts is used on each screw except on the screw that holds the back plate in place. One nut is used on each screw to give a distance between the component and the box and the other is used to tighten down the component.

Perfboard

Is used to mount all the components for the custom circuit for the LCD display.

Sheild for Arduino Nano with screw terminals

Used to make it easier to hook up the different compnents and also makes it easier to upgrade or change components later on.

Perfboard 25 mm X 45 mm

Is used to mount all the components for the relay circuit.

Perfboard 16 mm X 25 mm

Is used to mount all the components for the custom LCD display adapter.

Software apps and online services

Arduino IDE

Used for all programming.

Hand tools and fabrication machines

Soldering iron (generic)

Used to make the custom circuit board.

Helping Hand Tool, with Magnifying Glass

Not necessary but makes the work a lot easier.

Solder Wire, Lead Free

3D Printer (generic)

Hot glue gun (generic)

Cable Cutter, 143mm

Wire Stripper, Automatic

Plier, Long Nose

Screwdriver (philips head)

Story

Since the beginning of year 2020 the world have changed a lot due to covid-19 virus outbreak. People´s lives have changed a lot and everyone has in some way encounter the virus.

Due to the covid-19 virus it´s nowdays very important to take different messueres to reduce the risk of spreading the virus. This can be done in many ways and one of them is to avoid using buttons, switches and door handles in public areas.

But this is for the most part impossible because every door has a door handle and many doors and elevators requieres the use of button or swith. I have therefore came up with a solution where people can use solutions which includes buttons and switches without using their hands.

How it works

Note! This is a prototype which is scaled down to make possible to print it with a 3D-printer. The model is about five times smaller then what it schould be.

To reduce the spread of covid-19 there are many meassures that can be taken. One is meassure is to avoid toucing handles, switches and button in the public.

I have therefore came up with a solution to use doors with automatic door openers and other stuff like elevators without touching any thing with your hand.

By stepping on a plate made of 3D-printed plastic it actuates a built in push button which actuates a relay that controls a door or a elevator depending on the user´s choise.

This works because most doors/elevators that uses buttons have a voltage that is used to tell if the door should open or close depending on the state of a button. By instead using a relay instead of a button you can control doors and elevators without using the button at the door.

My solution consist of a base which have a push button mounted in it. It also have four springs which holds a plate. On the side of the base I also mounted a enclosure for a LCD display, a relay, two LED´s, an Arduino, a custom made cicuit board for the lcd and a SD-card reader/writer.

The base is placed on the floor and by steeping on the plate it´s pushed down and actuates the button in the base. The signal goes to an Arduino Nano Every which processes the signal.

The Arduino then sends out a signal to a custom made cicuit board which controls a 20x2 LCD display. The LCD then writes out the message "Make sure to keep your distance (2m)". After 5 seconds it displayes the messege "Wash your hands regularly!".

The Arduino then sends a signal to a NPN transistor which controls a relay. This relay can control external signals which can control automatic door openers, elevators, gates and other stuff that is some way controlled with a button or a switch.

There is also a red and a green LED which makes it easier to see when the door opens or closes. The red LED is lit when the door is closed and the green LED is lit when the door is opened.

Construction

The base is made of PLA plastic with a 3D-printer. The base have two ramps in the front and the back to make it easier to come up to the plate, especility for peoples in wheelchairs. In the middle of the base there is a hole for a pushbutton and a channel to hide cables.

On two sides (left and right) there is openings to let water out after rain if the device is placed outside.

The plate on top of the base is just a plate with four mounting holes for four springs. It also has two cut-out´s for the two ramps on the base.

There is also a box which holds the electronics. It holds the Arduino, relay, LCD, the circuit for the LCD and a 9V battery holder. Everything but the 9V battery holder is mounted with screws and nuts. The battery holder is glued to reduce the amount of screws that are seen. This also makes it harder for unauthorized persons to disassemble the unit.

Electronics

The electronics is based around an Arduino Nano Every. It´s suited for battery power and it´s small and powerful with many inputs and outputs. The Arduino Nano is fitted into a "shield" with screw terminals to make it esier to connect wires and to avoid unnecessary soldering. This also makes it esier to upgrade, change or remove parts if needed without soldering.

A SD-card reader/writer like shown in the schematic is connected to the Arduino Nano via the screw terminals.

The button placed in the base is also connected to the Arduino like shown in the scematic. It also has a 10K pull-down resistor to avoid random signals to the Arduino.

A second button is also connected to the Arduino. This buttton is used to turn off the Arduino and it´s data logging. This button needs to be pressed before the Arduino is powered off to make sure the data logging file closes correctly.

A relay is also connected to the Arduino. It´s used to control what ever device you want to control. It has a BC547B transistor which takes the signal from the Arduino and switches the transistor on and amplifies the signal to power the relay. The relay also has a diode to release the inductors charge when the relay is powered off.

To control the LCD I have built a custom made circuit board which is powered by the 9V battery. It has a ATMEGA328P to control the lcd and a voltage regulator with smothing capacitors to provide power to the circuit. There´s also a 16MHz crystal and two 22pF capacitors to make the clock for the IC. There´s also a 10k trimpotentiometer to adjust the contrast of the LCD and some female headers to connect the LCD.

The cicuit for the LCD is connected with a single wire to the Arduino for communication.

1 / 10

Programming

All of the programming is explained in the code.

I have during my programming used a libary for the LCD display and one for the SD-card reader/writer, both are built in the Arduino IDE.

Tools and materials

I have used simple tools like cutters and a wire stripper. I have also used a soldering iron to make the circuit boards. I recommend using a helping hand while doing the soldering but it´s not necessary.

I also used a 3D-printer with PLA filament.

The benefits of the solution

There are many benefits of the solution. The most obvius benefit is that there is no more need to use your hand to press a button or a switch to actuate a elevator or a automatic door opener. You simply step on the plate and the door openes.

There are also other benefits like doors and elevators gets more accseble and easier to reach and use especialy for people with some form of disability reduction.

The built in LCD-display also helps to reduce the risk of spreading the virus by informing and reminding users to keep a 1,5-2 meters distance to each other and also wash hands regularly.

Thanks to the built in SD-card reader/writer the owner can monitor the amount of visitors or users. The owner of the device can there for use that data to warn other visitors.

This way of using this solution, espacilaty with doors is also more energy-efficent. This is because the door needs interaction from a human and therefore does not open by passing people which lets much heat in or out of the building.

This solution is also very easy to install. It does not requiere any digging or prepariions to use it. It´s like a mat and can placed in front of most doors. It can also be used in combination with already exsisting buttons and does therefore not need to disassemble already exsisting solutions.

The message on the LCD display can easly be changed to whatever the owner wants.

About me

My name is Tim and I´m fourteen years old. I live in Sweden and I have a big interest in building stuff with electronics and other things as well as with 3D-printers and with my CNC-router.

Schematics

Code

#include <SPI.h> //Includes the SPI libary.
#include <SD.h> //Includes the SD libary.

File myFile; //Initilizes the SD libary. 

const int buttonPin = 2; //Varible for the pin which an external button is connected to. 
const int relayPin = 3; //Varible for the pin which the relay is connected to. 
const int exSignal = 5; //Varible for the pin for the signal to the LCD circuit. 
const int resetPin = 6; //Varible for the pin which the external reset button is connected to. 

int buttonState = 0; //Varible for the state of the external button. 
int resetButton = 0; //Varible for the state of the external reset button. 
int count = 0; //Varible for the counter which counts the users. 

unsigned long time = 0; //Creates a varible for time. 

void setup() {
  pinMode(buttonPin, INPUT); //Makes the pin for the external button to an input. 
  pinMode(relayPin, OUTPUT); //Makes the pin for the relay to an output.  
  pinMode(exSignal, OUTPUT); //Makes the pin for the signal to the LCD circuit to an output.
  pinMode(resetPin, INPUT); //Makes the pin for the reset button to an input. 

  SD.begin(4); //Starts the SD libary. 

  myFile = SD.open("Visitors.txt", FILE_WRITE); //Opens a .txt file with the name "Visitors".
  myFile.println("Counts the amount of visitors and writes down how many passes per hour under MAX 24H"); //Writes the following sentence in the file on the SD-card. 
}

void loop() {
  buttonState = digitalRead(buttonPin); //Stores the state of buttonPin in the buttonState varible.
  resetButton = digitalRead(resetPin); //Stores the state of the resetPin in the resetButton varible. 

  time = millis(); //Stores the time which has passed since the Arduino was powered on in the time varible. 
  
      
      if (resetButton == HIGH) { //If the reset button is pushed then start the secuence below. 
      myFile.print(count); //Prints the amount of users in the file on the SD-card.
      myFile.println("have used this device while it has been powered on."); //Prints the following sentence in the file on the SD-card. 
      myFile.close(); //Closes the file on the SD-card.
      {for(int i=0; i<10; i++) while(1);} //Goes into an endless loop which is a way to stop the program. 
  } else if (resetButton == LOW) { //If the reset button is off it will start the secuence below. 
     if (buttonState == HIGH){ //If the external button is pushed it will start the sequence below. 
        digitalWrite(exSignal, HIGH); //Turns on the external signal to the LCD ciruit. 
        count = count + 1; //Adds one to the counter to indicate that someone used the device.
        myFile.print("One person just used this device since: "); //Prints the messege "One person just used this device since: " when someone used the device. 
        myFile.print(time / 1000); //Prints the time stored in the time varible into the file on the SD-card. 
         //It also divides the value by 1000 to give it in seconds instead of microseconds.
        myFile.println("seconds it was started."); //Prints the following sentence in the file on the SD-card.  
        delay(10000); //Waits 10 seconds or 10000 microseconds before continuing. 
        digitalWrite(exSignal, LOW); //Turns off the external signal. 
        digitalWrite(relayPin, HIGH); //Turns on the relay. 
        delay(20000); //Waits 20 seconds or 20000 microseconds before continuing. 
      } else if (buttonState == LOW) { //If the state of the external button is low start the secuence below. 
        digitalWrite(exSignal, LOW); //Turns off the external signal to the LCD circuit. 
        digitalWrite(relayPin, LOW); //Turns off the power to the relay. 
     }}}

#include <LiquidCrystal.h> //Includes the liquid crystal display libary. 

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //Initilazies the LCD libary and tells which pins are used. 

const int signalPin = 6; //Variable for the pin which recieves the external signal. 
const int rows = 2; //Number of rows on your display. 
const int columns = 20; //Number of columns on your display. 
                        //Change to 16 if you are using a 16x2 lcd display.
int signalState = 0; //Variable for the state of the signal from Arduino Nano. 

void setup() {
  pinMode(signalPin, INPUT); //Makes the pin for external signal to a input.

  lcd.begin(columns, rows); //Sets up the display by telling number of coulmns and rows.
}

void loop() {
  signalState = digitalRead(signalPin); //Stores the state of the pin for external signal in a variable. 
  
  if (signalState == HIGH) {  //If theres power on pin 12 on the IC it will start the sequence below. 
    lcd.clear(); //Clears the display.
    lcd.setCursor(1, 0); //Selects the first row and second column. 
    lcd.print("Make sure to keep"); //Prints the messege "Make sure to keep".
    lcd.setCursor(1, 1); //Selects the second row and second column.
    lcd.print("your distance (2m)"); //Prints the messege "your distance (2m)".
    delay(5000); //Waits 5 seconds or 5000 microseconds before continuing.

    lcd.clear(); //Clears the display. 
    lcd.setCursor(2, 0); //Selects the first row and third column.
    lcd.print("Wash your hands"); //Prints the messege "Wash your hands".
    lcd.setCursor(5, 1); //Selects the second row and sixth column. 
    lcd.print("regularly!"); //Prints the messege "regularly!".
    delay(5000); //Waits 5 seconds before continuing.

    lcd.clear(); //Clears the display.
    lcd.setCursor(6, 0); //Selects the first row and sixth column.
    lcd.print("Thanks!"); //Prints the messege "Thanks!".
    delay(20000); //Waits 20 seconds or 20000 microseconds before continuing. 
  } 
  else if (signalState == LOW) { //If theres no power on pin 12 on IC it will start the sequence below. 
    lcd.clear(); //Clears the display.
    lcd.setCursor(1, 0); //Selects the first row and second column.
    lcd.print("Step on the plate"); //Prints the messege "Step on the plate".
    lcd.setCursor(3, 1); //Selects the second row and fourth column.
    lcd.print("to open door!"); //Prints the messege "to open door!".
  }}

Credits

timthegamer345600

1 project • 0 followers

The push plate

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

How it works

Construction

Electronics

Programming

Tools and materials

The benefits of the solution

About me

Custom parts and enclosures

Base

Top

Box for the electronics

Lid for the electronics box

Base

Base

Base

Schematics

Circuit scematic for the electronics

Code

Code for the Arduino

Code for the the external cicuit for the LCD

Credits

timthegamer345600

Comments

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The push plate

The push plate

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

How it works

Construction

Electronics

Programming

Tools and materials

The benefits of the solution

About me

Custom parts and enclosures

Base

Top

Box for the electronics

Lid for the electronics box

Base

Base

Base

Schematics

Circuit scematic for the electronics

Code

Code for the Arduino

Code for the the external cicuit for the LCD

Credits

timthegamer345600

Comments

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