Every project nowadays reaches for nice user interface. The display models from the company Nextion are quite famous due to their price and capabilities. The connection is made by a 3.3 V UART interface, either by a USB-TTL 3.3 V adapter or via the RasPi's onboard UART, if not already used. The software is written in Python can can be found here. https://github.com/rwth-afu/UniPagerNextion

Start-Animation of the Displays:

View from running mode:

View in 19 inch frame:

Possible suppliers:

• https://www.exp-tech.de/displays/lcd/7179/itead-studio-nextion-nx4024t032-generic-3.2-hmi-tft-intelligent-lcd-touch-display-module
• https://www.komputer.de/zen/index.php?main_page=product_info&products_id=354

In general, all display types from nextion are supported, but it is recommended to use as minimum the 3,2 inch version in order to have sufficient space on the display. The type code is NX4024T032 Link to the manufacturer. There is also a version with 4.2 inch available.

Be aware: The updates of Unipager may not always be compatible with the UniPagerNextion software. If something is not working after an update, let us know and write a ticket to

support at hampager.de

or open a ticket directly.

The working principle of this display control is devided in two parts:

• On the Nextion Display a special software is running to display the graphics and interact via a UART interface with the host running Unipager.
• On the host with Unipager, a Pyhton script is connecting via the websocket interface to Unipager. This makes it possible to get the status and config data from Unipager as well as sending the configuration manipulated on the touch screen display towards the Unipager.

Install unipager as described on the Unipager section of this wiki. Install git with

sudo apt-get install git

Clone the github repository containing all the software needed into a temporary directory, e.g. /home/pi

git clone https://github.com/rwth-afu/UniPagerNextion.git

cd into the directory of the install script and run it:

cd UniPagerNextion/src
sudo bash ./install.sh

This will install the python script to /usr/local/bin/unipagernextion.py and install a systemd service file named /usr/local/lib/systemd/system/unipagernextion.service. It will also register this service.

Now edit the config file in /etc/unipagernextionconfig.py according to your needs:

sudo nano /etc/unipagernextionconfig.py

# The config is just a python script which will be included

# The hostname, default localhost
#hostname = "localhost"

# The port, default 8055
#port = 8055

# Serial Port to the Nextion Display, default "/dev/ttyUSB0"
#serialport = "/dev/ttyUSB0"

# Serial Seppd to the Nextion Display, default 115200
#serialspeed = 115200

In the general case, no adaption is needed. As we have learned, not everybody is familiar with the concept of commenting-in und out Read more. So to be extremly clear here:

# Something means that Something is IS NOT active

Something means that Something IS active

Keep in mind to restart the UnipagerNextion service after altering the config file.

There are two ways of connection the Nextion display to the Raspberry Pi.

If you do not use the Raspager or RaspagerC9000, the GPIO is free to use. So you can conntect the four cables from the Nextion directly to the GPIO header.

Pin association to connect the Nextion display directly to the Raspberry Pi on-board UART.

RED 5 V Pin 02 or Pin 04

BLACK GND Pin 06 or any other ground Pin

GREEN Pin 10

YELLOW Pin 08

Remember: In the default raspbian image, on Raspberry Pi 3B and Raspberry Pi 3B+, the internal Bluetooth is connected to the internal UART. So as it is quite likely you won't use the Bluetooth, disable it by adding a line

dtoverlay=pi3-disable-bt

to /boot/config.txt and disable the Bluetooth service with

sudo systemctl disable hciuart

Also free the UART from the kernel messages by removing

console=serial0,115200

from /boot/cmdline.txt and enable the UART by adding

enable_uart=1

to /boot/config.txt

Further information is just one google search away: one google search away.

Reboot your Pi after doing these actions.

In case the onboard UART is not available, you can use a USB-to-Serial adapter.

There is a python script at https://github.com/rwth-afu/UniPagerNextion/tree/master/src. Edit the COM-Port according to your connection and run it with the .tft file. For firmware update of the display itself a programming with the Windows software from Nextion is recommended.