sda in lcd module made in china

What I understood was - ignoring the SD card module, they are using an LED driver IC to control the backlight, and a voltage regulator(with some auto reset IC) to feed the correct voltage to the LCD. Apart from that there"s some bypass caps on VCC and, some diodes on the LED driver IC.

I know how to join wires and connect resistors and bypass caps so if I feed the voltage through a buck converter at 3.3V, that only leaves me with the backlight that I"m not sure how to connect.

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As the maker movement has increasingly grown, we’d like to share the way to use Arduino and begin with controlling the LCD module. Yes, we’d like to start from LCD module instead of installation since makers can find lots of related information from the Internet. So we’ll have less basic introduction here.

After reading this article and manipulating, you will have the basic understanding of I2C bus and LCD, and learn the way to connect modules with Arduino, use basic program to control your LCD module, and think about the applications. The advanced control techniques will be explained in the future articles.

I2C Bus enables 2 devices to communicate with each other in a stable, high-speed, bidirectional way and with the least I/O pins. I2C Bus utilizes 2 lines to communicate, Serial Data Line (SDA) and Serial Clock Line (SCL), so that the protocol I2C uses is also called “bidirectional” protocol.

What’s more special is I2C Bus allows multiple devices to share the common communication lines. Thus, I2C Bus could control the communication function.

Here we use Arduino as the main board to control; pin A4 and A5 on the board are SDA and SCL pins respectively. To use I2C function, you would need to use Wire Library, which is the built-in library of Arduino IDE.

LCD is the abbreviation of liquid-crystal display; it’s a commonly-used display device and utilized everywhere in our daily life, from watches, calculators, TV to bulletin board.

This LCD module is the basic one and the most commonly-used character display; The voltage is 5V. The voltage level Arduino I/O Port uses is 5V so that we choose the LCD module. Besides, the LCD module can display 16 characters per line and there are 2 such lines. Also, the module uses I2C protocol. Thus, there are 4 pins on the module, including Vcc, GND, SDA, and SCL.

It is also easy to connect the wires. Firstly, you need to connect pin Vcc of the module to Arduino pin 5V, connect pin GND to Arduino pin GND, and connect pin SDA to Arduino pin A4. Lastly, connect pin SCL to Arduino pin A5 to complete the wiring.

Before introducing the sample, we’d like you to download the 3rd party libraries of I2C_LCD first. You can download the files here, decompress, and install. In this sample, the version we use is NewliquidCrystal_1.3.4. The followings are the codes we use for this sample.

Then, at the setting of initialization, LCD backlight will be controlled to blink 3 times. The first line will display “ICshop&MakerPRO” for one second, and the second line will display “Hello, Maker!” for 8 seconds. Then all the display will be cleared.

Hope all of you successfully complete the I2C_1602_LCD module display with the description mentioned above. If you failed, please check the wiring or you bought a defective device.

So next, you could think of if you can use the module to make a clock or environment sensors. You might have tons of ideas now! Why don’t you connect a LCD module in your next project?

I2C_LCD is an easy-to-use display module, It can make display easier. Using it can reduce the difficulty of make, so that makers can focus on the core of the work.

We developed the Arduino library for I2C_LCD, user just need a few lines of the code can achieve complex graphics and text display features. It can replace the serial monitor of Arduino in some place, you can get running informations without a computer.

More than that, we also develop the dedicated picture data convert software (bitmap converter)now is available to support PC platform of windows, Linux, Mac OS. Through the bitmap convert software you can get your favorite picture displayed on I2C_LCD, without the need for complex programming.

Select the board: Click Tools > Board > "Arduino Duemilanove or Diecimila"(Seeeduino V3.0 Or early version), "Arduino Uno"(Seeeduino Lotus or Seeeduino V4.0).

We have used Liquid Crystal Displays in the DroneBot Workshop many times before, but the one we are working with today has a bit of a twist – it’s a circle!  Perfect for creating electronic gauges and special effects.

LCD, or Liquid Crystal Displays, are great choices for many applications. They aren’t that power-hungry, they are available in monochrome or full-color models, and they are available in all shapes and sizes.

Today we will see how to use this display with both an Arduino and an ESP32. We will also use a pair of them to make some rather spooky animated eyeballs!

Waveshare actually has several round LCD modules, I chose the 1.28-inch model as it was readily available on Amazon. You could probably perform the same experiments using a different module, although you may require a different driver.

There are also some additional connections to the display. One of them, DC, sets the display into either Data or Command mode. Another, BL, is a control for the display’s backlight.

Another difference is simply with the labeling on the display. There are two pins, one labeled SDA and the other labeled SCL. At a glance, you would assume that this is an I2C device, but it isn’t, it’s SPI just like the Waveshare device.

This display can be used for the experiments we will be doing with the ESP32, as that is a 3.3-volt logic microcontroller. You would need to use a voltage level converter if you wanted to use one of these with an Arduino Uno.

The Arduino Uno is arguably the most common microcontroller on the planet, certainly for experiments it is. However, it is also quite old and compared to more modern devices its 16-MHz clock is pretty slow.

The Waveshare device comes with a cable for use with the display. Unfortunately, it only has female ends, which would be excellent for a Raspberry Pi (which is also supported) but not too handy for an Arduino Uno. I used short breadboard jumper wires to convert the ends into male ones suitable for the Arduino.

Once you have everything hooked up, you can start coding for the display. There are a few ways to do this, one of them is to grab the sample code thatWaveshare provides on their Wiki.

The Waveshare Wiki does provide some information about the display and a bit of sample code for a few common controllers. It’s a reasonable support page, unfortunately, it is the only support that Waveshare provides(I would have liked to see more examples and a tutorial, but I guess I’m spoiled by Adafruit and Sparkfun LOL).

Open the Arduino folder. Inside you’ll find quite a few folders, one for each display size that Waveshare supports. As I’m using the 1.28-inch model, I selected theLCD_1inch28folder.

Once you do that, you can open your Arduino IDE and then navigate to that folder. Inside the folder, there is a sketch file namedLCD_1inch28.inowhich you will want to open.

When you open the sketch, you’ll be greeted by an error message in your Arduino IDE. The error is that two of the files included in the sketch contain unrecognized characters. The IDE offers the suggestion of fixing these with the “Fix Encoder & Reload” function (in the Tools menu), but that won’t work.

The error just seems to be with a couple of the Chinese characters used in the comments of the sketch. You can just ignore the error, the sketch will compile correctly in spite of it.

The code is pretty basic, I’m not repeating all of it here, as it consists of several files.  But we can gather quite a bit of knowledge from the main file, as shown here.

You can see from the code that after loading some libraries we initialize the display, set its backlight level (you can use PWM on the BL pin to set the level), and paint a new image. We then proceed to draw lines and strings onto the display.

Unfortunately, Waveshare doesn’t offer documentation for this, but you can gather quite a bit of information by reading theLCD_Driver.cppfile, where the functions are somewhat documented.

After uploading the code, you will see the display show a fake “clock”. It’s a static display, but it does illustrate how you can use this with the Waveshare code.

As with the Waveshare sample, this file just prints shapes and text to the display. It is quite an easy sketch to understand, especially with the Adafruit documentation.

The sketch finishes by printing some bizarre text on the display. The text is an excerpt from The Hitchhiker’s Guide to the Galaxy by Douglas Adams, and it’s a sample of Vogon poetry, which is considered to be the third-worst in the Galaxy!

Here is the hookup for the ESP32 and the GC9A01 display.  As with most ESP32 hookup diagrams, it is important to use the correct GPIO numbers instead of physical pins. The diagram shows the WROVER, so if you are using a different module you’ll need to consult its documentation to ensure that you hook it up properly.

The TFT_eSPI library is ideal for this, and several other, displays. You can install it through your Arduino IDE Library Manager, just search for “TFT_eSPI”.

There is a lot of demo code included with the library. Some of it is intended for other display sizes, but there are a few that you can use with your circular display.

To test out the display, you can use theColour_Test sketch, found inside the Test and Diagnostic menu item inside the library samples.  While this sketch was not made for this display, it is a good way to confirm that you have everything hooked up and configured properly.

A great demo code sample is theAnimated_dialsketch, which is found inside theSpritesmenu item.  This demonstration code will produce a “dial” indicator on the display, along with some simulated “data” (really just a random number generator).

In order to run this sketch, you’ll need to install another library. Install theTjpeg_DecoderLibrary from Library Manager. Once you do, the sketch will compile, and you can upload it to your ESP32.

One of my favorite sketches is the Animated Eyes sketch, which displays a pair of very convincing eyeballs that move. Although it will work on a single display, it is more effective if you use two.

The first thing we need to do is to hook up a second display. To do this, you connect every wire in parallel with the first display, except for the CS (chip select) line.

The Animated Eyes sketch can be found within the sample files for the TFT_eSPI library, under the “generic” folder.  Assuming that you have wired up the second GC9A01 display, you’ll want to use theAnimated_Eyes_2sketch.

The GC9A01 LCD module is a 1.28-inch round display that is useful for instrumentation and other similar projects. Today we will learn how to use this display with an Arduino Uno and an ESP32.

The 1.8inch LCD uses the PH2.0 8PIN interface, which can be connected to the Raspberry Pi according to the above table: (Please connect according to the pin definition table. The color of the wiring in the picture is for reference only, and the actual color shall prevail.)

The example we provide is based on STM32F103RBT6, and the connection method provided is also the corresponding pin of STM32F103RBT6. If you need to transplant the program, please connect according to the actual pin.

ST7735S is a 132*162 pixel LCD, and this product is a 128*160 pixel LCD, so some processing has been done on the display: the display starts from the second pixel in the horizontal direction, and the first pixel in the vertical direction. Start to display, so as to ensure that the position corresponding to the RAM in the LCD is consistent with the actual position when displayed.

The LCD supports 12-bit, 16-bit and 18-bit input color formats per pixel, namely RGB444, RGB565, RGB666 three color formats, this routine uses RGB565 color format, which is also a commonly used RGB format

Note: Different from the traditional SPI protocol, the data line from the slave to the master is hidden since the device only has display requirement.

CPOL determines the level of the serial synchronous clock at idle state. When CPOL = 0, the level is Low. However, CPOL has little effect to the transmission.

CPHA determines whether data is collected at the first clock edge or at the second clock edge of serial synchronous clock; when CPHL = 0, data is collected at the first clock edge.

PS: If you are using the system of the Bullseye branch, you need to change "apt-get" to "apt", the system of the Bullseye branch only supports Python3.

Framebuffer uses a video output device to drive a video display device from a memory buffer containing complete frame data. Simply put, a memory area is used to store the display content, and the display content can be changed by changing the data in the memory.

Note: The script will replace the corresponding /boot/config.txt and /etc/rc.local and restart, if the user needs, please back up the relevant files in advance.

We have carried out the low-level encapsulation, if you need to know the internal implementation can go to the corresponding directory to check, for the reason that the hardware platform and the internal implementation are different

2.We use Dev libraries by default. If you need to change to BCM2835 or WiringPi libraries ,please open RaspberryPi\c\Makefile and modify lines 13-15 as follows:

If you need to draw pictures, or display Chinese and English characters, we provide some basic functions here about some graphics processing in the directory RaspberryPi\c\lib\GUI\GUI_Paint.c(.h).

Mirror: indicates the image mirroring mode. MIRROR_NONE, MIRROR_HORIZONTAL, MIRROR_VERTICAL, MIRROR_ORIGIN correspond to no mirror, horizontal mirror, vertical mirror, and image center mirror respectively.

Set points of the display position and color in the buffer: here is the core GUI function, processing points display position and color in the buffer.

The fill color of a certain window in the image buffer: the image buffer part of the window filled with a certain color, usually used to fresh the screen into blank, often used for time display, fresh the last second of the screen.

Draw rectangle: In the image buffer, draw a rectangle from (Xstart, Ystart) to (Xend, Yend), you can choose the color, the width of the line, whether to fill the inside of the rectangle.

Draw circle: In the image buffer, draw a circle of Radius with (X_Center Y_Center) as the center. You can choose the color, the width of the line, and whether to fill the inside of the circle.

Write Ascii character: In the image buffer, use (Xstart Ystart) as the left vertex, write an Ascii character, you can select Ascii visual character library, font foreground color, font background color.

Write English string: In the image buffer, use (Xstart Ystart) as the left vertex, write a string of English characters, you can choose Ascii visual character library, font foreground color, font background color.

Write Chinese string: in the image buffer, use (Xstart Ystart) as the left vertex, write a string of Chinese characters, you can choose character font, font foreground color, font background color of the GB2312 encoding

Write numbers: In the image buffer,use (Xstart Ystart) as the left vertex, write a string of numbers, you can choose Ascii visual character library, font foreground color, font background color.

Display time: in the image buffer,use (Xstart Ystart) as the left vertex, display time,you can choose Ascii visual character font, font foreground color, font background color.;

2. The module_init() function is automatically called in the INIT () initializer on the LCD, but the module_exit() function needs to be called by itself

Python has an image library PIL official library link, it do not need to write code from the logical layer like C, can directly call to the image library for image processing. The following will take 1.54inch LCD as an example, we provide a brief description for the demo.

The first parameter defines the color depth of the image, which is defined as "1" to indicate the bitmap of one-bit depth. The second parameter is a tuple that defines the width and height of the image. The third parameter defines the default color of the buffer, which is defined as "WHITE".

The first argument is a tuple of four elements. (20,10) is the coordinate value in the upper left corner of the rectangle, and (70,60) is the coordinate value in the lower right corner of the rectangle. Fill =" WHITE" means BLACK inside, and outline="BLACK" means the color of the outline is black.

Draw an inscribed circle in the square, the first parameter is a tuple of 4 elements, with (150, 15) as the upper left corner vertex of the square, (190, 55) as the lower right corner vertex of the square, specifying the level median line of the rectangular frame is the angle of 0 degrees, the second parameter indicates the starting angle, the third parameter indicates the ending angle, and fill = 0 indicates that the the color of the line is white.

The first parameter is the coordination of the enclosing rectangle. The second and third parameters are the beginning and end degrees of the circle. The fourth parameter is the fill color of the circle.

Note: Each character library contains different characters; If some characters cannot be displayed, it is recommended that you can refer to the encoding set ro used.

The first parameter is a tuple of 2 elements, with (40, 50) as the left vertex, the font is Font2, and the fill is the font color. You can directly make fill = "WHITE", because the regular color value is already defined Well, of course, you can also use fill = (128,255,128), the parentheses correspond to the values of the three RGB colors so that you can precisely control the color you want. The second sentence shows Micro Snow Electronics, using Font3, the font color is white.

The demo is developed based on the HAL library. Download the demo, find the STM32 program file directory, and open the LCD_demo.uvprojx in the STM32\STM32F103RBT6\MDK-ARM directory to check the program.

Open main.c, you can see all the test programs, remove the comments in front of the test programs on the corresponding screen, and recompile and download.

For the screen, if you need to draw pictures, display Chinese and English characters, display pictures, etc., you can use the upper application to do, and we provide some basic functions here about some graphics processing in the directory STM32\STM32F103RB\User\GUI_DEV\GUI_Paint.c(.h)

Mirror: indicates the image mirroring mode. MIRROR_NONE, MIRROR_HORIZONTAL, MIRROR_VERTICAL, MIRROR_ORIGIN correspond to no mirror, horizontal mirror, vertical mirror, and about image center mirror respectively.

Image buffer part of the window filling color: the image buffer part of the window filled with a certain color, generally as a window whitewashing function, often used for time display, whitewashing on a second

Draw rectangle: In the image buffer, draw a rectangle from (Xstart, Ystart) to (Xend, Yend), you can choose the color, the width of the line, whether to fill the inside of the rectangle.

Draw circle: In the image buffer, draw a circle of Radius with (X_Center Y_Center) as the center. You can choose the color, the width of the line, and whether to fill the inside of the circle.

Write Ascii character: In the image buffer, at (Xstart Ystart) as the left vertex, write an Ascii character, you can select Ascii visual character library, font foreground color, font background color.

Write English string: In the image buffer, use (Xstart Ystart) as the left vertex, write a string of English characters, can choose Ascii visual character library, font foreground color, font background color.

Write Chinese string: in the image buffer, use (Xstart Ystart) as the left vertex, write a string of Chinese characters, you can choose GB2312 encoding character font, font foreground color, font background color.

Write numbers: In the image buffer,use (Xstart Ystart) as the left vertex, write a string of numbers, you can choose Ascii visual character library, font foreground color, font background color.

Display time: in the image buffer,use (Xstart Ystart) as the left vertex, display time,you can choose Ascii visual character font, font foreground color, font background color.

DEV_Config.cpp(.h): It is the hardware interface definition, which encapsulates the read and write pin levels, SPI transmission data, and pin initialization;

image.cpp(.h): is the image data, which can convert any BMP image into a 16-bit true color image array through Img2Lcd (downloadable in the development data).

The hardware interface is defined in the two files DEV_Config.cpp(.h), and functions such as read and write pin level, delay, and SPI transmission are encapsulated.

For the screen, if you need to draw pictures, display Chinese and English characters, display pictures, etc., you can use the upper application to do, and we provide some basic functions here about some graphics processing in the directory GUI_Paint.c(.h)

Mirror: indicates the image mirroring mode. MIRROR_NONE, MIRROR_HORIZONTAL, MIRROR_VERTICAL, MIRROR_ORIGIN correspond to no mirror, horizontal mirror, vertical mirror, and about image center mirror respectively.

Draw rectangle: In the image buffer, draw a rectangle from (Xstart, Ystart) to (Xend, Yend), you can choose the color, the width of the line, whether to fill the inside of the rectangle.

Draw circle: In the image buffer, draw a circle of Radius with (X_Center Y_Center) as the center. You can choose the color, the width of the line, and whether to fill the inside of the circle.

Write Ascii character: In the image buffer, at (Xstart Ystart) as the left vertex, write an Ascii character, you can select Ascii visual character library, font foreground color, font background color.

Write English string: In the image buffer, use (Xstart Ystart) as the left vertex, write a string of English characters, can choose Ascii visual character library, font foreground color, font background color.

Write Chinese string: in the image buffer, use (Xstart Ystart) as the left vertex, write a string of Chinese characters, you can choose GB2312 encoding character font, font foreground color, font background color.

Write numbers: In the image buffer,use (Xstart Ystart) as the left vertex, write a string of numbers, you can choose Ascii visual character library, font foreground color, font background color.

Write numbers with decimals: at (Xstart Ystart) as the left vertex, write a string of numbers with decimals, you can choose Ascii code visual character font, font foreground color, font background color

void Paint_DrawFloatNum(UWORD Xpoint, UWORD Ypoint, double Nummber, UBYTE Decimal_Point, sFONT* Font, UWORD Color_Foreground, UWORD Color_Background);

Display time: in the image buffer,use (Xstart Ystart) as the left vertex, display time,you can choose Ascii visual character font, font foreground color, font background color.

While I was looking for a TFT display for a project with Arduino, I found on several webstores some displays based on the ST7735 chip by Sitronix (datasheet).

Based on its datasheet, the ST7735 chip has a SPI (Serial Peripheral Interface) interface, but the pin names on the silk screen of my display “seem” to suggest an I2C interface (SDA, SCL…):

First identify – based on your Arduino board – which pins correspond to the different signals of the SPI bus. For the others, you can freely choose between the remaining pins.

(as you see, I connected the BLK pin directly to Vcc to have the backlight always on. You can also connect it to an Arduino digital pin to be able to control the backlight via software, for example if you need to save power).

Adafruit wrote a fantastic tutorial to explain how to use them, here I only want to show you how to setup the display for the connections I made earler:

If you’re using a board based on the esp32 chip and you need to display bitmap images, give a look to my library, SPIFFS_ImageReader, which perfectly integrates with the ones by Adafruit!

“We have been looking forward to this visit from Adventist church leaders for a very long time,” student Elisha Ding said.  Ding is one of over one hundred young people being trained for ministry at the Beiguan Adventist Church in Shenyang, in the northern Chinese province of Liaoning.

Dressed in black suits, young men and women lined the walkway singing songs of welcome as a delegation from Adventist world church headquarters walked towards the church for evening worship.  Led by world church President Ted N. C. Wilson, the delegation was on an official ten-day visit to China to meet church members and local leaders.

Young people are trained for one year and during this time are given various responsibilities by their supervisors. After one year the best students are hand picked for additional theological training. Some students are also sent abroad as missionaries to various countries.

Beiguan Church had humble beginnings with twenty members meeting in someone’s home. Later, they shared a church in downtown Shenyang, later rented a church and finally had enough savings to build their own four-story building.

Many members took savings that they had kept for their children’s education and donated this to the church. People also gave much of their retirement savings. With winter approaching, construction workers needed to pour the concrete for the main pillars of the church in time to prevent cracking.

“The concrete had just been poured when a cold front passed causing great concern,” said Chinese Union President David Kok Hoe Ng. “Most church members brought their blankets from home and wrapped these around the pillars to save the building. It was quite a sight to see all these brightly colored blankets,” he added.

Today, the Beiguan Adventist Church has more than 3,000 members and has generated numerous church plants totaling another 7,000 members.  Every morning at 5 a.m., 365 days a year, church members come to the church to pray.

“The winters in the north are very cold and sometimes there are not too many people, but there are always at least one hundred members praying every morning,” Ng said.

Wilson reminded church members that God is calling them to carry on the work of revival and reformation. “You are a vital part of God’s worldwide people who are moving towards the Second Coming of Christ, a destiny that Christ himself has provided,” Wilson said.

The day before, the delegation visited the cultural city of Hangzhou, where Wilson greeted church members at Meilizhou Church inside an upmarket resort development.

This church also came about through sacrifice and the commitment and vision of key church members. A church elder and businessman saw an opportunity and contacted a friend who was a property developer. He told him that his resort had almost everything but one important element – a church.

The church elder contributed 25 percent of the funding and the developer paid the rest to build a church centrally located in the upmarket resort. Meilizhou Church’s membership is growing steadily as it serves the surrounding community.

"It is incredible to see the way our members are sacrificing their time and means to move forward the work of the Lord," said Adventist world church Treasurer Robert E. Lemon. "To see how our members have been able to build such a strong and vibrant church based almost completely on local volunteer support is thrilling."

In this one we’ll use it to connect a Keypad to an Arduino and again save some pins, and also have a quick overview on what and how the i2c protocol works.

I2C stands for “Inter-Integrated Circuit“, it allows to connect multiple modules or “slave”, and requires only 2 wires no matter the amount of connected modules, on an Arduino you can have up to 128 slave devices.

Those address are in hex values (ex. ox20), and most module give you the possibility to change the address by either soldering some pads or using dip switches like the I2C Expander module we used.

I2C uses two pins or signals, one is SCL and the other is SDA.  Most Arduinos have only one I2C bus, one exception would be the Arduino Due which has two seperate I2C bus.

Each one of those 8 pins/ports (P0-P7) can be independently used as an input, like we used it for when connecting the Bourns encoder or as an output to control some LEDs for example.

The main difference between those two modules, is their pinouts, the LCD Backpack pinout is made to fit on an LCD with additional outputs for the backlight.

Since both the I2C port Expander and the I2C LCD Backpack are pretty much the same, couldn’t I just use the LCD Backpack to connect the Bourns encoder?

But if your project can make due with only 7 I/O pins then you can use the LCD Backpack as an I2C Expander since those other pins are properly connected.

So instead of using 7 Pins on the Arduino, were’s using the I2C protocol and using only 2 Pins to read the Keypad as well as display the results on the LCD screen.

Connecting an LCD to your Raspberry Pi will spice up almost any project, but what if your pins are tied up with connections to other modules? No problem, just connect your LCD with I2C, it only uses two pins (well, four if you count the ground and power).

In this tutorial, I’ll show you everything you need to set up an LCD using I2C, but if you want to learn more about I2C and the details of how it works, check out our article Basics of the I2C Communication Protocol.

There are a couple ways to use I2C to connect an LCD to the Raspberry Pi. The simplest is to get an LCD with an I2C backpack. But the hardcore DIY way is to use a standard HD44780 LCD and connect it to the Pi via a chip called the PCF8574.

The PCF8574 converts the I2C signal sent from the Pi into a parallel signal that can be used by the LCD. Most I2C LCDs use the PCF8574 anyway. I’ll explain how to connect it both ways in a minute.

I’ll also show you how to program the LCD using Python, and provide examples for how to print and position the text, clear the screen, scroll text, print data from a sensor, print the date and time, and print the IP address of your Pi.

I2C (inter-integrated circuit) is also known as the two-wire interface since it only uses two wires to send and receive data. Actually it takes four if you count the Vcc and ground wires, but the power could always come from another source.

Connecting an LCD with an I2C backpack is pretty self-explanatory. Connect the SDA pin on the Pi to the SDA pin on the LCD, and the SCL pin on the Pi to the SCL pin on the LCD. The ground and Vcc pins will also need to be connected. Most LCDs can operate with 3.3V, but they’re meant to be run on 5V, so connect it to the 5V pin of the Pi if possible.

If you have an LCD without I2C and have a PCF8574 chip lying around, you can use it to connect your LCD with a little extra wiring. The PCF8574 is an 8 bit I/O expander which converts a parallel signal into I2C and vice-versa. The Raspberry Pi sends data to the PCF8574 via I2C. The PCF8574 then converts the I2C signal into a 4 bit parallel signal, which is relayed to the LCD.

Before we get into the programming, we need to make sure the I2C module is enabled on the Pi and install a couple tools that will make it easier to use I2C.

Now we need to install a program called I2C-tools, which will tell us the I2C address of the LCD when it’s connected to the Pi. So at the command prompt, enter sudo apt-get install i2c-tools.

Next we need to install SMBUS, which gives the Python library we’re going to use access to the I2C bus on the Pi. At the command prompt, enter sudo apt-get install python-smbus.

Now reboot the Pi and log in again. With your LCD connected, enter i2cdetect -y 1 at the command prompt. This will show you a table of addresses for each I2C device connected to your Pi:

We’ll be using Python to program the LCD, so if this is your first time writing/running a Python program, you may want to check out How to Write and Run a Python Program on the Raspberry Pi before proceeding.

I found a Python I2C library that has a good set of functions and works pretty well. This library was originally posted here, then expanded and improved by GitHub user DenisFromHR.

There are a couple things you may need to change in the code above, depending on your set up. On line 19 there is a function that defines the port for the I2C bus (I2CBUS = 0). Older Raspberry Pi’s used port 0, but newer models use port 1. So depending on which RPi model you have, you might need to change this from 0 to 1.

The function mylcd.lcd_display_string() prints text to the screen and also lets you chose where to position it. The function is used as mylcd.lcd_display_string("TEXT TO PRINT", ROW, COLUMN). For example, the following code prints “Hello World!” to row 2, column 3:

On a 16×2 LCD, the rows are numbered 1 – 2, while the columns are numbered 0 – 15. So to print “Hello World!” at the first column of the top row, you would use mylcd.lcd_display_string("Hello World!", 1, 0).

You can use the time.sleep() function on line 7 to change the time (in seconds) the text stays on. The time the text stays off can be changed in the time.sleep() function on line 9. To end the program, press Ctrl-C.

You can create any pattern you want and print it to the display as a custom character. Each character is an array of 5 x 8 pixels. Up to 8 custom characters can be defined and stored in the LCD’s memory. This custom character generator will help you create the bit array needed to define the characters in the LCD memory.

The code below will display data from a DHT11 temperature and humidity sensor. Follow this tutorial for instructions on how to set up the DHT11 on the Raspberry Pi. The DHT11 signal pin is connected to BCM pin 4 (physical pin 7 of the RPi).

By inserting the variable from your sensor into the mylcd.lcd_display_string() function (line 22 in the code above) you can print the sensor data just like any other text string.

These programs are just basic examples of ways you can control text on your LCD. Try changing things around and combining the code to get some interesting effects. For example, you can make some fun animations by scrolling with custom characters. Don’t have enough screen space to output all of your sensor data? Just print and clear each reading for a couple seconds in a loop.

Let us know in the comments if you have any questions or trouble setting this up. Also leave a comment if you have any other ideas on how to get some cool effects, or just to share your project!

Many drawing and writing primitives are provided: single pixel plotting, lines, circles, triangles, rectangles (with square and rounded corners), and corresponding filled shapes. Text and numeric values, may be placed anywhere on the screen in a variety of sizes. Bitmapped shapes can be scrolled or moved about the screen and the whole screen can be rotated.

Points are defined by their Cartesian co-ordinates, (x, y). The origin (0, 0) is at the top left of the screen. Increasing the y value moves down the screen. The addressable dimensions of the SSD1306 screen are 128 pixels left to right (0, 1, 2, …, 127) and 64 pixels from top to bottom (0, 1, 2, …, 63). The pixel in the bottom right corner is (127, 63).

(x0, y0) and (x1, y1) would define the first two positions, while h is the height and w the width of an object. A radius is r. All dimensions are in pixels. The colour is specified by c, SSD1306_WHITE or SSD1306_BLACK.

These are based on the system used for printing to the Serial monitor with print() and println(). The font included with the library is 5 pixels wide and 7 pixels tall but prints into a 6x8 pixel space.

None of these instructions will produce a change on the screen without a display.display(); method. If your script does not appear to be working check you have included this line at the bottom of your screen changing code.

Holding the serial module with the I2C interface at the left hand end, there are 16 pins at the lower edge. The first of these is ground, and the second of these is +5v. Another option is to use the lower two pins on the I2C interface for power, but I found it more convenient to use the pins as described above.

I2C interface. On the serial module, the top pin is SCL (clock) and it goes to the Arduino A5. The second pin down is SDA (data) and it goes to the Arduino A4.

LCD print interface. There are 6 connections between the serial module and the LCD Keypad shield, all of them between pins with no labels. I will identify them on the LCD module by counting from Right to Left, with the first pin as 1. There are 2 blocks of 8, so they go from 1 to 16. I identify them on the I2C serial module by counting from Left to Right, there are also 16 of these. In addition I give each wire a label, which is the equivalent pin on the Arduino that is normally associated with that function, in the case of a direct connection without the serial module.

Keypad interface: This uses a single wire from the LCD module pin on the lower side labelled "A0", to pin A0 on the Arduino. At least that was pretty easy!

MELBOURNE, Australia — China has at least 200 stealthy J-20 fighters and more than 240 J-16 multirole strike aircraft in service, based on analysis of construction numbers painted on the jets by a Chinese military aviation expert.

Andreas Rupprecht, who has authored several books on China’s military aviation industry and the People’s Liberation Army Air Force, told Defense News that based on the construction numbers seen on the jets at the Zhuhai Airshow, there have been four production batches of the J-20 and 11 batches of J-16s.

He noted that two of the Chengdu J-20 fighters at the show had “CB0369″ and “CB0370″ painted in small letters behind the canopy of the jets. Based on previous examples seen in public or on photos and videos released by China, “CB03″ would indicate the jets were from the fourth production batch, with “CB00″ being the first.

The last two digits of the construction number indicate the running number of that particular batch, with the jets at the air show being the 69th and 70th aircraft in the fourth production batch of J-20s.

He added that, based on his previous research, his “conservative estimate” is that the previous three production batches of J-20s had at least 18, 46 and 56 airframes, respectively. And adding 70 aircraft to the fourth batch and approximately 18 low-rate production platforms would bring the total J-20 production to 208 aircraft.

The presence of J-20s on static display at the air show has allowed photographers to obtain better resolution images of the aircraft than previously possible. The jets at the show, which runs Nov. 8-13, were powered by indigenous WS-10C engines and features low-observable sawtooth edges on their afterburner nozzles.

Justin Bronk, a senior research fellow for air power and technology at the U.K.-based think tank Royal United Services Institute, said “the surface detail shots show just how much progress the Chinese aircraft industry has made on manufacturing tolerance and quality control.”

Bronk told Defense News that based on photos of the J-20 low-rate initial production aircraft, which took part in the flying display at the 2018 Zhuhai Airshow, “China continues to make progress in closing the gap with U.S. low-observable designs.”

Meanwhile, the J-16 on static display this year carried the construction number “1105″ on the outside of its air intakes. According to Rupprecht, this indicates the aircraft was the fifth one of the 11th production batch.

He added that Shenyang Aircraft Corp., which manufactures the J-16, uses a more straightforward construction number and production batch system, with each batch numbering 24 aircraft. This means the aircraft at the show — which is assigned to the 172nd Air Brigade of the People’s Liberation Army Air Force — is the 245th production J-16.

The J-16 started entering PLAAF service in 2015. It is based on the Chinese J-11B interceptor and the Russian Sukhoi Su-30MK series, both of which can trace their lineage back to the Sukhoi Su-27 Flanker interceptor.

China has developed an electronic-attack version of the J-16 known as the J-16D. The type made its debut at the last Zhuhai Airshow in 2021 and appeared again at this year’s show.