2021/04/28 ｜By G Editor
Raspberry Pi has become the first choice for makers because of its compact size, low price, free and diverse software, and community resources. Although the original intention of Raspberry Pi is to assist students in computer science learning, the rapid progress of open-source software such as Linus and Python has led to many Raspberry Pi enthusiasts creating their own robots, servers, IOT devices, Industrial equipment networking devices, or even supercomputers by connecting multiple Raspberry Pi.
When using the Raspberry Pi as a server or industrial monitoring device, it is naturally inevitable to be combined with a touch screen. This article will explain in detail how to connect an external capacitive touch monitor with Raspberry Pi, and execute the touch calibration program to obtain more sensitive and precise touch operation.
Different generations of Raspberry Pi models have different I/O port configurations, but they all have HDMI and USB ports. Here we use Raspberry Pi 3 Model B and On-Lap M505T to demonstrate the connection.
(Note: The Raspberry Pi does not have a power switch. After the power port is connected, the system will boot immediately. Be sure to complete the above steps before inserting the power cable.
When the Raspberry Pi OS is successfully installed for the first time, it will automatically enter the Raspi-Config screen—that is, the Raspbian system configuration interface.
If your Raspberry Pi OS has been already installed, please enter Terminal >> key in 〖sudo raspi-config〗 to open the setting screen
There are many versions of Raspi-Config, please select “Display Options”; if there is no Display Options, please select “Advanced Options” to find resolution menu.
Click<Tab> button on keyboard to switch down and select＜OK＞to save
Click the Termianl icon on the task bar and run Terminal
key in the following instructions inside Terminal 〖wget http://github.com/downloads/tias/xinput_calibrator/xinput_calibrator-0.7.5.tar.gz〗
Key in〖tar -zxvf xinput_calibrator-0.7.5.tar.gz〗in Terminal
Key in〖cd /home/pi/xinput_calibrator-0.7.5〗
Key in 〖sudo apt-get install libx11-dev libxext-dev libxi-dev x11proto-input-dev〗
under /xinput_calibrator-0.7.5 directory , input the following instructions.
〖sudo make install〗
Key in〖sudo xinput_calibrator〗
Key in〖sudo mkdir /etc/X11/xorg.conf.d〗 (watch out the Caps)
Key in〖sudo nano /etc/X11/xorg.conf.d/99-calibration.conf〗
Click right button of mouse and select "Paste"＞＞Press "ctrol+O" to save >>click "Enter"
Raspberry Pi supports a variety of mobile operating systems, but the most recommended for the beginners is Raspberry Pi OS (also known as Raspbian), developed by the Raspberry Pi Foundation based on Debian. Beginners can simply download and install Raspbian through Raspberry Pi Imager.
After you purchase the Raspberry Pi, please prepare one SD memory card above 8G, and follow the steps below to install Raspbian.
The resolution options of Raspbian are divided into CEA (HDMI_group=1; for TV) and DMT (HDMI_group=2; for monitor). DMT should be selected for general computer monitors. The following table shows the resolution options commonly used for external HDMI monitors:
Note: The common 7-inch Raspberry Pi touch module on the market has a resolution of 1024x600. There is no such option in the Resolution menu of Raspbian, so you have to go to config.txt, enter hdmi_mode=87 and use the hdmi_cvt command to assign the display value.