clear lcd screen arduino pricelist

Currently I have code to swipe in rfid tags to a reader which then using the arduino Uno it lights up an LED coordinating to which tag was swiped. What I"m looking to do now is set a dollar amount to each tag and once a tag is swiped in add it to like a current total price and then output that to LCD Screen. Is this possible with Arduino Uno? Anyone help with this?

In this guide we’re going to show you how you can use the 1.8 TFT display with the Arduino. You’ll learn how to wire the display, write text, draw shapes and display images on the screen.

The 1.8 TFT is a colorful display with 128 x 160 color pixels. The display can load images from an SD card – it has an SD card slot at the back. The following figure shows the screen front and back view.

This module uses SPI communication – see the wiring below . To control the display we’ll use the TFT library, which is already included with Arduino IDE 1.0.5 and later.

The TFT display communicates with the Arduino via SPI communication, so you need to include the SPI library on your code. We also use the TFT library to write and draw on the display.

In which “Hello, World!” is the text you want to display and the (x, y) coordinate is the location where you want to start display text on the screen.

The 1.8 TFT display can load images from the SD card. To read from the SD card you use the SD library, already included in the Arduino IDE software. Follow the next steps to display an image on the display:

In this guide we’ve shown you how to use the 1.8 TFT display with the Arduino: display text, draw shapes and display images. You can easily add a nice visual interface to your projects using this display.

You can find the previous article here. It contains a description of the LCD module, shows you how to connect the display to your Arduino UNO board and describes the basic rules of operating it using the software. Still, it needs to be admitted here that there is only a limited number of applications for an LCD alone, because in the case of such a simple LCD module no settings can be entered. To do so, you need a keyboard, which we will discuss in detail in one of the future articles, but now let us use a ready-made solution from the Arduino ecosystem – a board from Olimex – SHIELDLCD16x2.

This is a shield board which extends Arduino capabilities, equipped with an LCD module (2 lines of 16 characters each), 4 buttons and 8 additional GPIO lines. On the board, there is a PIC processor which communicates with Arduino UNO via the TWI interface. With access to a library of functions, operating this module with a built-in microcontroller should not cause any major problems. Let"s start with preparing the module for operation.

There are two steps to prepare the module for work: hardware and software. The first one is simply to plug the shield into the Arduino UNO board. The second one requires you to install a library of module operating functions.

To install the library, go to the module manufacturer"s website i.e. Olimex. Then, in the search box (next to the Search button) enter the part of the module name "LCD16x2". (Figure 1). Click on the Search button. When this text was being created, the search retuned two results – please, select "SHIELD-LCD16x2".

Under the description of the module, you can find the "SOFTWARE" section (figure 2). Each line of text in this section is also a link to a file that can be downloaded from the Olimex website. At this point, we are looking for the link saying: "OLIMEXINO-328 + SHIELD-LCD16x2 – a library and set of demo examples".

Download the ZIP file available at this link to your computer. Of course, it is worth having a look at the available examples, but for our needs it is enough to install the library saved in the LCD16x2 catalogue.

The Arduino IDE allows for various different ways of installing libraries. In this case, the easiest way is to upload the sources to the project directory, which also contains a libraries subdirectory. The project directory is created during the installation of Arduino IDE, and Windows usually places it (in the Polish language version) in subdirectory Ten Komputer → Dokumenty → Arduino. To add the library sources to today"s example, just move the LCD16x2 directory to the libraries folder. Once you"ve done that, launch the Arduino IDE.

Before getting started with your own program, you should read examples of using the LCD16x2.h library of functions available in the Examples directory. It is a much more effective method of learning than reading documentation, although it is worth remembering about the latter as well.

As mentioned before, the shield communicates with the UNO board using a serial interface. It"s easy to guess that the functions described in the previous article must be modified, because they used a parallel, 4-bit interface. As you can imagine, the microcontroller on the shield board communicates with the LCD character display module in the same way, but our Arduino UNO cannot "see" the display, and the control is done indirectly. Therefore, start the program by adding libraries to support the appropriate serial interface and the display module mounted on the shield board.

To make it simple, in order not to use the long library name, it is recommended to assign to it the lcd alias. We will use it by writing the name of the library function after the dot.

As you remember from the previous article, programs created for Arduino are divided into two parts: the initialization function and the infinite loop. The commands of the first one are written in the void setup() function, and of the latter – in the void loop() function. The commands contained within the setup function are executed only once, while those within the infinite loop are executed throughout the program.

The initialization function starts the TWI interface, clears the LCD screen, and turns on the display backlight at the maximum LED light intensity (0 parameter turns off the backlight).

Mask 0x01 corresponds to the first button on the left, while 0x08 corresponds to the first button on the right. The program numbers the buttons by giving the pressed variable a value corresponding to the conventional button number. Then, this number is shown on the LCD screen, at the position starting in the first row and the first column. The message is displayed only if the pressed value is different from 0. Otherwise, the message "No button" is displayed, indicating that no button is pressed. The message is terminated with three spaces so that when overlaid on "1 is pressed" (which is longer) the last characters of the caption are cleared.

The whole sketch is available in the resources attached to the article. Compile it and upload it to the Arduino UNO microcontroller memory using the Ctrl+U shortcut (Sketch → Upload).

I put it to clear a certain part of the lcd where the millisecond counter is. It never cleared. When i replaced the lcd.print(""); with lcd.print("."); it displayed an period where I wanted the nothing.

It takes the same time for the hardware to implement lcd.clear() for a 16x2 or a 20x4 screen. i.e. about 2ms whether by parallel or backpack. It also resets the cursor to 0, 0.

In this Arduino tutorial we will learn how to connect and use an LCD (Liquid Crystal Display)with Arduino. LCD displays like these are very popular and broadly used in many electronics projects because they are great for displaying simple information, like sensors data, while being very affordable.

You can watch the following video or read the written tutorial below. It includes everything you need to know about using an LCD character display with Arduino, such as, LCD pinout, wiring diagram and several example codes.

An LCD character display is a unique type of display that can only output individual ASCII characters with fixed size. Using these individual characters then we can form a text.

The number of the rectangular areas define the size of the LCD. The most popular LCD is the 16×2 LCD, which has two rows with 16 rectangular areas or characters. Of course, there are other sizes like 16×1, 16×4, 20×4 and so on, but they all work on the same principle. Also, these LCDs can have different background and text color.

It has 16 pins and the first one from left to right is the Groundpin. The second pin is the VCCwhich we connect the 5 volts pin on the Arduino Board. Next is the Vo pin on which we can attach a potentiometer for controlling the contrast of the display.

Next, The RSpin or register select pin is used for selecting whether we will send commands or data to the LCD. For example if the RS pin is set on low state or zero volts, then we are sending commands to the LCD like: set the cursor to a specific location, clear the display, turn off the display and so on. And when RS pin is set on High state or 5 volts we are sending data or characters to the LCD.

Next comes the R/W pin which selects the mode whether we will read or write to the LCD. Here the write mode is obvious and it is used for writing or sending commands and data to the LCD. The read mode is used by the LCD itself when executing the program which we don’t have a need to discuss about it in this tutorial.

After all we don’t have to worry much about how the LCD works, as the Liquid Crystal Library takes care for almost everything. From the Arduino’s official website you can find and see the functions of the library which enable easy use of the LCD. We can use the Library in 4 or 8 bit mode. In this tutorial we will use it in 4 bit mode, or we will just use 4 of the 8 data pins.

We will use just 6 digital input pins from the Arduino Board. The LCD’s registers from D4 to D7 will be connected to Arduino’s digital pins from 4 to 7. The Enable pin will be connected to pin number 2 and the RS pin will be connected to pin number 1. The R/W pin will be connected to Ground and theVo pin will be connected to the potentiometer middle pin.

We can adjust the contrast of the LCD by adjusting the voltage input at the Vo pin. We are using a potentiometer because in that way we can easily fine tune the contrast, by adjusting input voltage from 0 to 5V.

Yes, in case we don’t have a potentiometer, we can still adjust the LCD contrast by using a voltage divider made out of two resistors. Using the voltage divider we need to set the voltage value between 0 and 5V in order to get a good contrast on the display. I found that voltage of around 1V worked worked great for my LCD. I used 1K and 220 ohm resistor to get a good contrast.

There’s also another way of adjusting the LCD contrast, and that’s by supplying a PWM signal from the Arduino to the Vo pin of the LCD. We can connect the Vo pin to any Arduino PWM capable pin, and in the setup section, we can use the following line of code:

It will generate PWM signal at pin D11, with value of 100 out of 255, which translated into voltage from 0 to 5V, it will be around 2V input at the Vo LCD pin.

First thing we need to do is it insert the Liquid Crystal Library. We can do that like this: Sketch > Include Library > Liquid Crystal. Then we have to create an LC object. The parameters of this object should be the numbers of the Digital Input pins of the Arduino Board respectively to the LCD’s pins as follow: (RS, Enable, D4, D5, D6, D7). In the setup we have to initialize the interface to the LCD and specify the dimensions of the display using the begin()function.

The cursor() function is used for displaying underscore cursor and the noCursor() function for turning off. Using the clear() function we can clear the LCD screen.

So, we have covered pretty much everything we need to know about using an LCD with Arduino. These LCD Character displays are really handy for displaying information for many electronics project. In the examples above I used 16×2 LCD, but the same working principle applies for any other size of these character displays.

I hope you enjoyed this tutorial and learned something new. Feel free to ask any question in the comments section below and don’t forget to check out my full collection of 30+ Arduino Projects.