arnholm / tvcec

Control TV using HDMI-CEC from Raspberry PI. Moved to https://gitlab.com/arnholm

tvcec

Control TV using HDMI-CEC from Raspberry PI. For example, assuming you are using a TV with 2 HDMI input sources and not using an antenna connection.

HDMI 1 = Chromecast
HDMI 2 = Raspberry PI

The idea with tvcec is to run as a UDP server and receive messages for controlling the TV via HDMI. This is achieved by issuing commands to the TV via the cec-client application that must be installed on the PI:

sudo apt install cec-utils

tvcec messages

TV Function	tvcec UDP message	cec-client command
on	cec-on {addr}	on {addr}
standby	cec-standby {addr}	standby {addr}
volume up	cec-volup	volup
volume down	cec-voldown	voldown
mute	cec-mute	mute
Source HDMI 1	cec-hdmi 1	txn 4f:82:10:00
Source HDMI 2	cec-hdmi 2	txn 4f:82:20:00
Source HDMI {n}	cec-hdmi {n}	txn 4f:82:{n}0:00
n/a	exit	n/a !

The cec-client commands are issued as in this example (turn TV on):

echo "on 0" | cec-client -s -d 1

Disable Raspberry PI screen saver

If you are switching to the HDMI input source corresponding to the Raspberry PI, it might be that the PI screen saver is activated and then you see only a blank screen. To avoid this, it is possible to permanently disable Raspberry PI screen saver. Edit this file to do it:

sudo nano /etc/lightdm/lightdm.conf

add the following line under the [Seat:*] section:

xserver-command=X -s 0 dpms

After a reboot, the screen saver will be permanently disabled (to re-enable screen saver remove the line and reboot).