Touchscreen

What the touchscreen is for

A touchscreen connected directly to the server displays Calaos Home, the local Calaos interface. It shows your home — rooms, lights, shutters, temperatures — and lets you control it with your finger.

It is also used for a few operations on the system itself:

• configuring the network;
• changing the login credentials;
• changing its own language;
• installing Calaos OS onto the disk, from Live mode;
• confirming a rollback.

Server screen or wall screen?

Do not confuse two different things:

• the screen connected to the server, which this page is about. There is only one, where the machine is;
• the Remote UI wall screens, spread across the rooms of the house, which connect to the server over the network.

If your goal is to have wall controls in several rooms, Remote UI screens are what you want: see Remote UI.

Setting it up

Connect the screen to the server’s video output, and its touch cable to a USB port, before switching the machine on. At boot, Calaos Home is displayed automatically.

If you connect the screen while the server is already running, restart it so that the screen is detected:

reboot

If the screen stays black

Check in this order:

1. is the screen powered and switched on? Many screens have their own switch;
2. is the video cable properly connected at both ends, and to the right output if the machine has several;
3. is the screen on the right input? A screen set to HDMI 2 while you are plugged into HDMI 1 stays black;
4. is the server running anyway? Try connecting to it over SSH: if that works, the problem is purely a display one.

To understand what is happening on the display side, check the logs:

journalctl -b | grep -i -E "drm|display|xorg"

Calibrating touch

If touch works but lands next to where you press — you tap a button and its neighbour reacts — the screen needs calibrating.

Connect over SSH and run:

xinput_calibrator

A calibration screen appears: touch each cross as it shows up in the corners. At the end, the values are saved automatically in the right place, in /mnt/calaos/xorg.conf.d. There is no file to copy or edit.

Then restart so the new calibration is taken into account:

reboot

If touch does not respond at all

If the picture is displayed but touch does nothing, the touch part is not recognised. It usually goes through a cable separate from the video cable: check that it is properly connected.

To see whether the system detects a touch device:

libinput list-devices

Touchscreen connected through a USB / serial adapter

Some screens, particularly resistive ones, do not plug in directly over USB: they use a serial link, connected to the computer through a USB/serial adapter. These screens are not detected automatically, so the matching service must be enabled.

First find the name of the device created by the adapter:

ls /dev/ttyUSB*

It is most often ttyUSB0. Then enable the service with that name, and start it:

systemctl enable usb-serial-touchscreen@ttyUSB0.service
systemctl start usb-serial-touchscreen@ttyUSB0.service

If your adapter appears under another name — ttyUSB1 for instance — replace it in both commands.

Once the service is active, touch is recognised and you can calibrate it as described above.

To check that the service runs correctly:

systemctl status usb-serial-touchscreen@ttyUSB0.service

Screen sleep

A wall screen left on permanently wears out and lights up the room at night. Calaos OS can therefore switch it off automatically after a while without use, and switch it back on as soon as it is touched.

These settings are made with the calaos_config tool:

calaos_config set dpms_enable true
calaos_config set dpms_standby 2

dpms_enable turns sleep on, and dpms_standby sets the idle delay before it triggers, expressed in minutes. In the example above, the screen switches off after two minutes without use.

Sleep is disabled by default. If you enable it without setting a delay, the screen switches off after one minute.

To stop the screen from switching off — useful for a supervision screen that must stay visible at all times — simply disable sleep:

calaos_config set dpms_enable false

The mouse cursor

On a purely touch-driven screen, the mouse pointer is useless and sits in the middle of the display. To hide it:

calaos_config set show_cursor false

Set the value back to true if you connect a mouse to the machine.

Forcing the connection to a specific server

By default the interface finds a Calaos server on its own on the local network and connects to it. In the vast majority of cases there is therefore nothing to configure.

If automatic discovery does not suit you — several servers on the same network, or a remote screen that must target one specific machine — give the server address:

calaos_config set calaos_server_host 192.168.1.50

An IP address is enough. You can also give a full address if your setup requires it, for instance to go through an encrypted connection:

calaos_config set calaos_server_host wss://myhome.calaos.fr/api

calaos_config del calaos_server_host

Going further

The display and calibration settings specific to your installation are kept in /mnt/calaos/xorg.conf.d. As this folder is part of your data, its contents survive updates — see Backing up your configuration.