micropython lcd display quotation

I am looking for a simple library to pilot an LCD 1602 from WeMos D1 Mini (or other esp8266). Looking for simple API to send text on line 1 or 2, maybe adjust dim. Things like that.

The 5V Pin of the Wemos D1 is connected via a Diode to the 5V Bus of USB. I cannot read the sign of that diode on my device, but some datasheets say B5819, which is a 1 A Schottky diode. Since the ESP8266 consumes about 200 mA max, there are at least 300mA available for the display power, assuming 500 mA from USB. I recommend to add an an additional buffering capacitor at the 5V.

lcd.display(image[, x=0[, y=0[, x_scale=1.0[, y_scale=1.0[, roi=None[, rgb_channel=-1[, alpha=256[, color_palette=None[, alpha_palette=None[, hint=0[, x_size=None[, y_size=None]]]]]]]]]]]])¶

@jcaron I see that the Raspberry Pi official website recommends using micropython to write, if python can also do it, I can also try it, but I searched the Internet to see the examples, even using python to write it also need to use the micropython library.

It seems reasonable to guess that lcd_display_string() will output a string on the display. (Reading the documentation for the module you are using is recommended.)

This repository contains all the code for interfacing with a 16x2 character I2C liquid-crystal display (LCD). This accompanies my Youtube tutorial: Raspberry Pi - Mini LCD Display Tutorial.

During the installation, pay attention to any messages about python and python3 usage, as they inform which version you should use to interface with the LCD driver. For example:

It is possible to define in CG RAM memory up to 8 custom characters. These characters can be prompted on LCD the same way as any characters from the characters table. Codes for the custom characters are unique and as follows:

For example, the hex code of the symbol ö is 0xEF, and so this symbol could be printed on the second row of the display by using the {0xEF} placeholder, as follows:

It can display a number in just about any size. It can display decimal, hexadecimal, octal or binary numbers. It is easy to connect to data sources using the display() slot, which is overloaded to take any of five argument types.

QLCDNumber emits the overflow() signal when it is asked to display something beyond its range. The range is set by setDigitCount() , but setSmallDecimalPoint() also influences it. If the display is set to hexadecimal, octal or binary, the integer equivalent of the value is displayed.

These digits and other symbols can be shown: 0/O, 1, 2, 3, 4, 5/S, 6, 7, 8, 9/g, minus, decimal point, A, B, C, D, E, F, h, H, L, o, P, r, u, U, Y, colon, degree sign (which is specified as single quote in the string) and space. QLCDNumber substitutes spaces for illegal characters.

It is not possible to retrieve the contents of a QLCDNumber object, although you can retrieve the numeric value with value() . If you really need the text, we recommend that you connect the signals that feed the display() slot to another slot as well and store the value there.

Constructs an LCD number, sets the number of digits to 5, the base to decimal, the decimal point mode to ‘small’ and the frame style to a raised box. The segmentStyle() is set to Outline .

Constructs an LCD number, sets the number of digits to numDigits , the base to decimal, the decimal point mode to ‘small’ and the frame style to a raised box. The segmentStyle() is set to Filled .

This property corresponds to the nearest integer to the current value displayed by the LCDNumber. This is the value used for hexadecimal, octal and binary modes.

Corresponds to the current display mode, which is one of Bin , Oct , Dec (the default) and Hex . Dec mode can display floating point values, the other modes display the integer equivalent.

Corresponds to the current display mode, which is one of Bin , Oct , Dec (the default) and Hex . Dec mode can display floating point values, the other modes display the integer equivalent.

To break this down I created a while loop that displays a number, sleeps for 3 seconds, increments the number and then runs back through the loop checking the integer is not greater than 10.

Connecting an LCD display to your Raspberry Pi is sure to take any project up a notch. They’re great for displaying sensor readings, songs or internet radio stations, and stuff from the web like tweets and stock quotes. Whatever you choose to display, LCDs are a simple and inexpensive way to do it.

In this tutorial, I’ll show you two different ways to connect an LCD to the Raspberry Pi with the GPIO pins. The first way I’ll show you is in 8 bit mode, which uses 10 GPIO pins. Then I’ll show you how to connect it in 4 bit mode, and that uses only 6 pins. After we get the LCD hooked up I’ll show you how to program it with C, using Gordon Henderson’s WiringPi LCD library.

I’ll show you how to print text to the display, clear the screen, position the text, and control the cursor. You’ll also see how to scroll text, create custom characters, print data from a sensor, and print the date, time and IP address of your Pi.

There’s another way to connect your LCD that uses only two wires, called I2C. To see how to do that, check out our tutorial How to Set Up an I2C LCD on the Raspberry Pi.

Most people probably want to connect their LCD in 4 bit mode since it uses less wires. But in case you’re interested, I’ll show you how to connect it in 8 bit mode as well.

In 8 bit mode, each command or character is sent to the LCD as a single byte (8 bits) of data. The byte travels in parallel over 8 data wires, with each bit travelling through it’s own wire. 8 bit mode has twice the bandwidth as 4 bit mode, which in theory translates to higher data transfer speed. The main downside to 8 bit mode is that it uses up a lot of GPIO pins.

In 4 bit mode, each byte of data is sent to the LCD in two sets of 4 bits, one after the other, in what are known as the upper bits and lower bits. Although 8 bit mode transfers data about twice as fast as 4 bit mode, it takes a longer time for the LCD driver to process each byte than it takes to transmit the byte. So in reality, there isn’t really a noticeable difference in speed between 4 bit mode and 8 bit mode.

WiringPi is a C module that makes it easy to program the LCD. If you already have WiringPi installed on your Pi, you can skip this section. If not, follow the steps below to install it:

To use different pins to connect the LCD, change the pin numbers defined in lines 5 to 14. You’ll need to convert the WiringPi pin numbers to the physical pin numbers of the Raspberry Pi. See here for a diagram you can use to convert between the different numbering systems.

To use the LCD in 4 bit mode, we need to set the bit mode number to 4 in the initialization function (line 20 below). The following code prints “Hello, world!” to the screen in 4 bit mode:

By default, text is printed to the screen at the top row, second column. To change the position, use lcdPosition(lcd, COLUMN, ROW). On a 16×2 LCD, the rows are numbered from 0 to 1, and the columns are numbered from 0 to 15.

The function lcdClear(lcd) clears the screen and sets the cursor position at the top row, first column. This program prints “This is how you” for two seconds, clears the screen, then prints “clear the screen” for another two seconds:

Each LCD character is a 5×8 array of pixels. You can create any pattern you want and display it on the LCD as a custom character. Up to 8 custom characters can be stored in the LCD memory at a time. This website has a nice visual way to generate the bit array used to define custom characters.

To print a single custom character, first define the character. For an example of this see lines 12 to 19 below. Then use the function lcdCharDef(lcd, 2, omega) to store the character in the LCD’s memory. The number 2 in this example is one of the 8 locations in the LCD’s character memory. The 8 locations are numbered 0-7. Then, print the character to the display with lcdPutchar(lcd, 2), where the number 2 is the character stored in memory location 2.

As an example to show you how to display readings from a sensor, this program prints temperature and humidity readings to the LCD using a DHT11 temperature and humidity sensor. To see how to set up the DHT11 on the Raspberry Pi, see our article How to Set Up the DHT11 Humidity Sensor on the Raspberry Pi.

Hopefully this helped you get your LCD up and running on your Raspberry Pi. The programs above are just basic examples, so try combining them to create interesting effects and animations.

If you have any problems or questions about installing the LCD or programming it, just leave a comment below. And don’t forget to subscribe to get an email when we publish new articles. Talk to you next time!

LCD character displays are a useful way to get output from a microcontroller. The one used on this page is a fairly standard size, able to display 2 rows of 16 characters. The advantage we have over the LED matrix is that we don"t need to have our text scrolling across the screen. This allows us to display things like sensor readings so that we can see them change in real time.

The most common standard for the controllers built into these displays is the Hitachi HD44780 LCD controller protocol. This is a parallel interface (we need to send signals down several wires at the same time). For many microcontrollers that have been around longer than the micro:bit (like Arduino), there are libraries to help you interact with common hardware like this. Although no such libraries exist for the micro:bit, I have been able to make a rough conversion of the Arduino library code for use with the micro:bit.

The HD44780 LCD controller interface is made up of 16 connections, not all of which are needed to communicate with the display. On most modules, these are broken out to 0.1 inch spaced pins and are in the following order,

We will need to connect up LCD pins 1 & 2 to our power pins on the micro:bit as well as connecting LCD pins 15 & 16 up to the power to make the backlight work. The resistor for this light is built into the display module.

The RS pin needs to connect to a GPIO pin. It is set to LOW when we send commands to the display (like clearing the screen or moving the cursor) and set to 1 when we are sending character data.

The RW pin is set to LOW when writing to the LCD and set to HIGH when reading. We don"t need to read from the display so we can save ourselves a GPIO pin by connecting this pin directly to GND.

There are 8 data pins. We can operate the display in either 8 bit or 4 bit mode. 4 bit mode means 4 rather than 8 connections. When we use 4 bit mode, we only connect up D4 - D7 to our GPIO pins. This does mean that we will be sending our bytes in two parts and will be a little slower when updating the display but will save us 4 GPIO connections.

The micro:bit hasn"t been around long enough for there to be many examples of how to connect to these or any hardware libraries that provide simple functions for you to use. This has been converted from the open source Arduino library with the timings for delays rounded up. This makes the communication a little slower than can be achieved but more than good enough for most uses you want to make of the LCD.

I have left in most of the constants from the library. If you explore a little, you will be able to use these to make use of more of the built-in functionality of the display (like blinking and scrolling text).

The little section at the end is the most important for you. The 4 "high level" functions are the ones that you will use to interact with the display after you have called the InitDisplay() function once at the start of your program. Some parts of the Arduino library send the same command several times - I have copied the approach taken there and things work - that was enough for me.

Output hardware like this can be put to many uses. Anything that you display by scrolling across the LEDs will be easier to read on this display. That might be the score for a game or the reading you are getting from a sensor connected on a GPIO pin.

Use the display to make a stopwatch. Use running_time rather than delays to control your timings and think carefully about how often you update the display.

I programmed a MicroBit to run an LCD display. I tried two different versions of Python - MakeCode and MicroPython and was surprised by some of the differences.https://youtu.be/xgo0Bp7cWkE

lcd.line(x, y, x1, y1 [,clr]) to draw a line from the point with coordinates x,y to coordinates x1, y1. If clr is not specified, it will use the current text color;

lcd.ellipse(x, y, rx, ry [opt, clr, fillcolor]) draw oval with centre at the point with coordinates x, y and elongated region rx, ry. opt - argument indicating which edges will be displayed, the default value of 15 - all segments. You can display certain segments simultaneously, it is necessary to use the logical OR operator to the values of opt: 1 - first quarter 2 first quarter 4 - second quarter, 8 in the fourth quarter. If clr is not specified, it will use the current text color. If fillcolor is not specified, the figure is shaded;

lcd.arc(x, y, r, thick, start, end, [clr, fillcolor]) draw an arc with a thickness thick with the center with coordinates x, y, radius, start angle start and end end. If clr is not specified, it will use the current text color. If fillcolor is not specified, the figure is shaded;

lcd.poly(x, y, r, sides, thick, [clr, fillcolor, rotate]) is to draw the polyhedron with the center with coordinates x, y, radius, number of sides sides, outline width thik, color clr, fill color, fillcolor, rotate rotate. If clr is not specified, it will use the current text color. If fillcolor is not specified, the figure will not be filled. The range of values of the angle specified in degrees from 0 to 359;

lcd.rect(x, y, w, h, [clr, fillcolor]) draw a rectangle with coordinates x, y, width w, height h, color clr, fill color fillcolor. If clr is not specified, it will use the current text color. If fillcolor is not specified, the figure is shaded;

lcd.roundrect(x, y, w, h, r [clr, fillcolor]) draw a rectangle with rounded edges with a bend radius r from the point with coordinates x, y, width w, height h, color clr, fill color fillcolor. If clr is not specified, it will use the current text color. If fillcolor is not specified, the figure will not be filled. The range of values of the angle specified in degrees from 0 to 359;

lcd.orient(orient) set the orientation of the display. Can be used the following constants: lcd.PORTRAIT - portrait lcd.LANDSCAPE - landscape, lcd.PORTRAIT_FLIP - portrait is reversed, lcd.LANDSCAPE_FLIP - infinity inverted;

lcd.font(font [,rotate, trsprt, fixedw, dist, w, outline, clr]) to set the font and its parameters. Where font is the name of the constant font or the font file name, rotate (optional) - angle; trsprt transparency; fixedw - to set a fixed character width, dist (only for seven-segment font) is the distance between familiarity, w (only for-segment font) - width familiarity, outline (only for the seven-segment font) - the delineation of the contour, clr - color of the text;

lcd.attrib7seg(dist, w, outline, clr) set parameters seven-segment font. Where dist is the distance between familiarity, w - the width of familiarity,

lcd.text(x, y, text [, clr]) to display the text with color clr to the point with coordinates x, y. If clr is not specified, it will use the current text color. You can also use constants: X: CENTER - align text center,

lcd.textClear(x, y, text [, clr]) - clears the text area of the text located at x, y coordinates, and then fills in with color clr. If clr is not specified, it will use the current background color;

Use constants lcd.CENTER, lcd.BOTTOM lcd.RIGHT, and Boolean operators such as X&Y. X and Y can be negative numbers. Scaling JPG: value sc may be within the range of integers from 0 to 3; If sc > 0, then the image will be scaled according to the formula 1 / (2 ^ sc), etc. (1/2, 1/4 or 1/8).

tp (optional) - specifies the type of image: lcd.JPG or lcd.BMP. If not specified, to determine the type of image will use the file extension and/or contents of the file;

lcd.hsb2rgb(hue, saturation, brightness) - convert HSB to RGB. Returns a 24-bit integer color value. Arguments: tint (fractional) - any number, half that number is subtracted from it to create a fraction between 0 and 1. This fractional number is then multiplied by 360 to get the angle of hue in a color model in the HSB system.

lcd.compileFont(file_name [,debug]) - compile the font from source file (.C) in binary code (.fon). If needs report output for debugging use debug = True. If you want to get the file source code font, then use the app

7-segment displays, the kind found on old digital alarm clocks, can be great for Raspberry Pi projects, including those you make with Raspberry Pi Pico. You can use a 7-segment display to keep score in a game, show sensor data like temperature or distance numbers or to keep track of time. You can even show some letters.

There are many kinds of 7-segment displays on the market and they vary not only based on the number of digits and the color, but also on the controller board or lack thereof. Some cheap 7-segment displays have no controller and use separate pins for every single light. When you consider that each digit has seven different lights (hence the name “7-segment display”), that’s a lot of pins.

However, better 7-segment displays have controller boards which employ an I2C connection that uses just four pins, powered by a TM1637 controller board. Below, we’ll show you how to use one of these TM1637-powered 7-segment displays with a Raspberry Pi Pico.

The 7-segment display has four pins: CLK, DIO, GND and VCC. If you use female-to-female jumper wires, you don’t need a breadboard to do the connections.

We’re going to rely heavily on the excellent TM1637 MicroPython library from Mike Causer and create a script which shows a variety of display options, which you can use in your own projects later on.

6. Copy tm1637.py to your Pico’sroot directory. Since the Pico with MicroPython doesn’t appear as a drive letter, the easiest way to do this is to open tm1637.py in Thonny or the IDE or your choice and save it from there.

9. Create an instance of the tm1637.TM1637 object called “mydisplay” and enter the correct pin numbers for the CLK and DIO pins as parameters.mydisplay = tm1637.TM1637(clk=Pin(16), dio=Pin(17))

10. Use the “show” method to display any four characters. These can be letters or numbers, but note that many letters, W for example, will look awkward. If you enter more than four characters, only the first four will be shown. Be sure to put the parameter string in quotes.mydisplay.show(“Pico”)

Note that if you don’t blank the display, it will remain on when your program is finished executing. You don’t need to blank the display when changing it, but if you use another show command with less than the maximum number of characters, any characters you don’t replace will stay on the screen. For example, if you do show(“halo”) and then show(“20”), the screen will read 20lo.

12. Use the “number” method to show an integer. Do not put quotes around the parameter. You can display a negative or positive number, but if it’s a negative number, it has to reserve one character for the minus sign. Note that, if you enter a larger number than the available number of digits (ex: entering 12345 on four-digit display), the screen will read “9999” or “-999” for negative numbers.mydisplay.number(-123)

15. Use the “scroll” method to display scrolling text. Enter a string (in quotes) as the first parameter and add, “delay=” and a number of milliseconds to control the speed of the scroll. If you skip the delay parameter, it will default to 250ms.mydisplay.scroll("Hello World 123", delay=200)

16. Use the “temperature” method to show a temperature in Celsius. This method adds the degree symbol and letter C after your digits. You enter either a one or two digit integer as the temperature and you can do negative temperatures but these can only be one digit.mydisplay.temperature(99)

There are other methods that Causer documents on his github page, including one that will convert numbers to hexadecimal format for you or take hex input. However, these are the main methods we think most people will need to get use with a 7-segment display and Raspberry Pi Pico.