Power on/off an Acer projector using a USB-to-RS232C dongle.

acer_projector_control.sh

#!/bin/ash

# Serial port device (adjust this based on your system)
SERIAL_PORT="/dev/ttyUSB0"

# Function to configure the serial port
configure_serial() {
    if [ ! -c "$SERIAL_PORT" ]; then
        echo "Error: $SERIAL_PORT is not a valid character device"
        exit 1
    fi
    # Set baud rate to 115200, 8N1 (8 data bits, no parity, 1 stop bit)
    stty -F "$SERIAL_PORT" 9600 cs8 -parenb -cstopb || {
        echo "Error: Failed to configure $SERIAL_PORT"
        exit 1
    }
}

# Function to send command
send_command() {
    local command="$1"
    # Echo the command with a carriage return (\r) to the serial port
     echo -e "$command" > "$SERIAL_PORT" || {
        echo "Error: Failed to send command to $SERIAL_PORT"
        exit 1
    }
}

# Main logic
case "$1" in
    on)
        configure_serial
        send_command "* 0 IR 001"
        echo "Projector turning ON"
        ;;
    off)
        configure_serial
        send_command "* 0 IR 002"
        echo "Projector turning OFF"
        ;;
    *)
        echo "Usage: $0 {on|off}"
        exit 1
        ;;
esac

exit 0

To power the projector automatically on at 6 PM and off at 1 AM every day add the following lines to the crontab file:

00 18 * * * /location_of_the_script/acer_projector_control.sh on
00 01 * * * /location_of_the_script/acer_projector_control.sh off