raspberry pi lcd display i2c made in china

Honestly 14$ vs let"s say 25$ would be acceptable, but the original displays are at 40$. From a shop which delivers to Germany it would be around 50$.

Oh mostly by coincidence I found a very similar display: http://www.wide.hk/index.php?route=prod ... duct_id=66 Here it makes associations between the pin descriptions:

Required a bit of measuring to find out what pins are connected on the bonnet and also a bit of guessing, but the first display worked instantly and the second soon after.

Looking good! That"s nice to combine with this housing: https://www.sossolutions.nl/raspberry-p ... dinrail-2b (DIN-rail) so you can fit it into your meter cabinet.

HW: HP dc7900 USD running ESXi, RaspberryPi (few of it), AEON S2 USB stick, Fibaro modules (Dimmers, switches), 1-wire (DS18B20, DS2423), DSC Alarm with Envisalink ethernet module, MySensors, RFLink

Check the number in the table, this is your address. If there are more devices on your I2c bus, there will be several addresses visible. To be sure, unplug all other devices and the address left will be the LCD (or try them all)

HW: HP dc7900 USD running ESXi, RaspberryPi (few of it), AEON S2 USB stick, Fibaro modules (Dimmers, switches), 1-wire (DS18B20, DS2423), DSC Alarm with Envisalink ethernet module, MySensors, RFLink

The principle of the LCD1602 liquid crystal display is to use the physical characteristics of the liquid crystal to control the display area by voltage, that is, the graphic can be displayed.

I2C uses only two bidirectional open-drain lines, Serial Data Line (SDA) and Serial Clock Line (SCL),pulled up with resistors. Typical voltages used are +5 V or +3.3 V although systems with other voltages are permitted. It can be operated as long as it supports the I2C development board.

Features: Easy to use; Less I/O ports are occupied; Support IIC Protocol; The I2C LCD1602 library is easy to get; With a potentiometer used to adjust backlight and contrast; Blue backlight; Power supply: 5v; I2C address is: 0x27.

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 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.

In previous posts I’ve covered using HD44780 16×2 and 20×4 LCD screens with the Raspberry Pi using Python. These are relatively easy to use but require a number of connections to be made to the Pi’s GPIO header. This setup can be simplified with the use of an I2C enabled LCD screen.

This requires a high level voltage (5V) and a low level voltage (3.3V) which the device uses as a reference. The HV pins can be connected to the screen and two of the LV pins to the Pi’s I2C interface.Level ShifterPiI2C Backpack

While experimenting I found that it worked fine without the level shifting but I couldn’t be certain this wasn’t going to damage the Pi at some point. So it’s probably best to play it safe!

The example script will allow you to send text to the screen via I2C. It is very similar to my scripts for the normal 16×2 screen. To download the script directly to your Pi you can use :wget https://bitbucket.org/MattHawkinsUK/rpispy-misc/raw/master/python/lcd_i2c.py

In order to use I2C devices you must enable the interface on your Raspberry Pi. This can be done by following my “Enabling The I2C Interface On The Raspberry Pi” tutorial. By default the I2C backpack will show up on address 0x27.

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LCD screens are useful and found in many parts of our life. At the train station, parking meter, vending machines communicating brief messages on how we interact with the machine they are connected to. LCD screens are a fun way to communicate information in Raspberry Pi Pico projects and other Raspberry Pi Projects. They have a big bright screen which can display text, numbers and characters across a 16 x 2 screen. The 16 refers to 16 characters across the screen, and the 2 represents the number of rows we have. We can get LCD screens with 20x2, 20x4 and many other configurations, but 16x2 is the most common.

In this tutorial, we will learn how to connect an LCD screen, an HD44780, to a Raspberry Pi Pico via the I2C interface using the attached I2C backpack, then we will install a MicroPython library via the Thonny editor and learn how to use it to write text to the display, control the cursor and the backlight.

2. Import four librariesof pre-written code. The first two are from the Machine library and they enable us to use I2C and GPIO pins. Next we import the sleep function from Time enabling us to pause the code. Finally we import the I2C library to interact with the LCD screen.from machine import I2C, Pin

3. Create an objecti2c to communicate with the LCD screen over the I2C protocol. Here we are using I2C channel 0, which maps SDA to GP0 and SCL to GP1.i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)

4. Create a variableI2C_ADDR,which will store the first I2C address found when we scan the bus. As we only have one I2C device connected, we only need to see the first [0] address returned in the scan.I2C_ADDR = i2c.scan()[0]

5. Create an objectlcdto set up the I2C connection for the library. It tells the library what I2C pins we are using, set via the i2c object, the address of our screen, set via I2C_ADDRand finally it sets that we have a screen with two rows and 16 columns.lcd = I2cLcd(i2c, I2C_ADDR, 2, 16)

6. Create a loopto continually run the code, the first line in the loop will print the I2C address of our display to Thonny’s Python Shell.while True:

8. Write two lines of textto the screen. The first will print “I2C Address:” followed by the address stored inside the I2C_ADDR object. Then insert a new line character “\n” and then write another line saying “Tom’s Hardware" (or whatever you want it to say). Pause for two seconds to allow time to read the text.lcd.putstr("I2C Address:"+str(I2C_ADDR)+"\n")

9. Clear the screenbefore repeating the previous section of code, but this time we display the I2C address of the LCD display using its hex value. The PCF8574T chip used in the I2C backpack has two address, 0x20 and 0x27 and it is useful to know which it is using, especially if we are using multiple I2C devices as they may cause a clash on the bus.lcd.clear()

12. Turn the backlight back onand then hide the cursor. Sometimes, a flashing cursor can detract from the information we are trying to communicate.lcd.backlight_on()

13. Create a for loopthat will print the number 0 to 19 on the LCD screen. Note that there is a 0.4 second delay before we delete the value and replace it with the next. We have to delete the text as overwriting the text will make it look garbled.for i in range(20):

Save and runyour code. As with any Python script in Thonny, Click on File >> Saveand save the file to your Raspberry Pi Pico. We recommend calling it i2c_lcd_test.py. When ready, click on the Green play buttonto start the code and watch as the test runs on the screen.

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.