Arduino Vending Machine

 Arduino Vending Machine

For this practice we have to create an arduino program and use some sensors and actuators in order to simulate a real coffee vending machine.

HARDWARE COMPONENTS:

  • Joystick
  • DHT11 (humidity and temperature sensor)
  • Ultrasonic sensor
  • Boton
  • 2 Leds
  • LCD
  • Arduino Uno

What is its behavior ?

We are going to have 3 different behavior stages 

1) Loading mode:

The led 1 is going to blink 3 times at 1 seconds intervals. At the same time that we are executing the blinks of the led, we are going to write a loading message ("CARGANDO...") in the LCD; after that, it is going to entry to the service mode.

2) Service Mode:

We are going to print a waiting for client message ("ESPERANDO CLIENTE") at the LCD until the distance sensors get a 1 meter or less detection, simulating the client detection.

When the client has been detected, we are going to show the products at the LCD and letting the client search for the product that he wants using the joystick (up / down) and  the switch of the button to confirm the selection.

Finally, we are going to show a "preparing coffee message" at the LCD and a "get the drink message" when the preparation time have finished.  

* If the client wants to restart this mode, he just have to press the button during 3 seconds.

3) Admin mode:
Whenever the user want, he can push the button during 5 seconds or more and the 2 leds will light up and the machine will enter at the admin mode.

In this mode a menu will be displayed at the LCD and he will navigate through it using the joystick.
This menu have 4 options, one for display the humidity and temperature detected by the DHT11 sensor, other for display the distance to an object detected by the distance sensor, another one for showing how much time has been pass(in seconds) since the machine started working; and the last one is going to allow the user to change the prices of the products confirming with the switch of the joystick what item price want to change and what price does he want, and  moving the joystick up and down changing the item selected and its price. 

How does it really work?

1) How are we going to do the led blink?

For this, we are going to use the Arduinothread library, creating a thread that will execute the blink function in the correct moment and which, when it has make the led blink 3 times, is going to be disabled. 

2) Get distance form the distance sensor.

The ultrasonic sensor uses sonar to determine the distance to an object




The time between the transmission and reception of the signal allows us to calculate the distance to an object. This is possible because we know the sound's velocity in the air.


3) Show text at the LCD:

For this we are going to use the LiquidCrystal library.   

The most important functions of this library are: 
  • LiquidCrysta lcd(correct arudino pins)  -> create an LCD object
  • ldc.clear() -> clean the screen
  • ldc.setCursor(row, col) -> select where do you want to start writing at the LCD
  • ldc.print(text) -> show the text at the LCD
4) Calculate the time since the machine started to work.

We use the library TimerOne to execute a software interruption every second which will increment a counter of seconds.

5) Button Control:

We have already seen that our machine is going to be having a planned behavior but it has to change his state as sons as the button is pressed. To achieve this, we are going to use the attachinterrupt() function to get a hardware interruption that is going to control the behavior of the vending machine when the button is pressed. Also we are going to wait some time before execute the code of the button callback, in order to avoid the button bounces.

6) Humidity and temperature lectures:

We use the library DHT-sensor-library created by adafruit to get this measures.

The most important functions of this library are: 
  • dht DHT  -> create a dht object
  • DHT.read11(dhtpin) -> read the input of the sensor and actualize the attributes of the DHT object 
  • DHT.temperature -> get the temperature (which is an attribute of the DHT object)
  • DHT.humidity -> get the humidity (which is an attribute of the DHT object)

7) Joystick lectures:

We just have to connect the joystick to the analog pines of our arduino and read it values in order to determine if the joystick has been moved, and for the switch, it just work as a normal button.

8) Coffee preparation simulation:

We are just going to use the random function to generate a random number which is going to represent the time during which we are preparing the coffee.

See a demo:


See the schematic circuit:



 * The DHT11 sensor and joystick of the image are not the same as the ones that I used, but the components connection is the same. 








Comentarios

Publicar un comentario

Entradas populares de este blog

Localized Vacuum Cleaner

Imagen
Localized Vacuum Cleaner For this practice, we are going to design the control system for a high-end vacuum cleaner. High-end vacuum cleaners stand out from the rest due to their more powerful sensors, which are required to enable the use of more optimal home cleaning algorithms. In this case, the algorithm we are going to use is the Backtracking Spiral Algorithm (BSA) for coverage. Backtracking Spiral Algorithm (BSA): This algorithm involves dividing the provided simulation world map into cells. The size of these cells will depend on the dimensions of the robot, and it is recommended that they have a slightly smaller size than the robot's diameter to prevent the robot from passing over the same area of the world multiple times, which would be represented by different cells in our auxiliary map. We will also classify our cells into three types: obstacle, already visited, and dirty. We will also expand the obstacles on the map using erosion to avoid getting too close to them and to
Leer más

Autonomous drone for search and rescue mission

Imagen
Autonomous drone for search and rescue mission For this exercise, we will design the control system for a drone intended for search and rescue missions. To assess the effectiveness of our program, we will simulate a shipwreck scenario. In this hypothetical situation, we will be informed of the presence of shipwreck survivors (with an unknown number of individuals) at specific coordinates. Our drone will need to navigate to the designated area, sweep the vicinity for survivors, report to the rescue team, and ultimately return to the takeoff zone. Drone behavior: For the fulfillment of our mission, we will implement a state machine in which our drone will start from the 'disarmed' state, needing to arm and take off before transitioning to the 'go to survivors' state. Once the drone is in the last sighting zone, it will switch to the 'search' state, where it will perform a spiral sweep and record the location of any spotted survivor. Finally, upon completing the se
Leer más

OMPL Amazon warehouse

Imagen
 OPML AMAZON WAREHOUSE The objective of this exercise is to empower our robot to transfer a designated shelf from its initial location to a distinct area, utilizing a supplied map and shelf locations as points of reference. In my scenario, I have chosen the initial point as the destination. Additionally, it is crucial to highlight that we were constrained to crafting movement paths solely through the utilization of the OMPL library, a factor that has notably streamlined the entire task. How have I achieved it? First version The initial step involved configuring the robot to generate routes using OMPL. To achieve this, it was necessary to establish bidirectional mappings between the map and real-world coordinates, enabling seamless coordinate base transformations. Subsequently, I approximated the robot as a point (or pixel, in this context) and applied erosion to the map using a kernel size equivalent to the robot's pixel size plus an inflated area, akin to the approach employed by
Leer más