Recently I built a series of special effects for the scenography of the play "Strange House" by Leonardo Cortez. The set design was composed of several white boxes, all identical, as if the family were moving to a new house. On the lid of one of these boxes, built like a chest, was a TV from the 80's, with manual channel selector, made with rotary selector switch. Here I share how I solved this challenge.

For this tutorial, I'm guessing you already know how to install Raspberry Pi OS and how to program it in Python. But if you don't know, I recommend the step by step on the Raspberry Pi OS website itself - https://www.raspberrypi.org/software/

I'll divide this tutorial into steps to make it easier to understand. First, I eliminated the rainbow screen, the default splash screen, all system startup messages, redirecting them to another console (tty3). For this, I followed the instructions of this link: https://scribles.net/customizing-boot-up-screen-on-raspberry-pi/

Which are basically these:

Remove any sign that you are in a computer system

Remove Rainbow Screen:

Open “/boot/config.txt” as root.

sudo nano /boot/config.txt

Then add below line at the end of the file.

disable_splash=1

Remove text message under splash image:

Open “/usr/share/plymouth/themes/pix/pix.script” as root.

sudo nano /usr/share/plymouth/themes/pix/pix.script

Then, remove (or comment out) four lines below:

message_sprite = Sprite();
message_sprite.SetPosition(screen_width * 0.1, screen_height * 0.9, 10000);
       my_image = Image.Text(text, 1, 1, 1);
       message_sprite.SetImage(my_image);

Note : This is a quick and dirty method I found. It works, but there might be better way.

Remove Boot Messages

Open “/boot/cmdline.txt” as root.

sudo nano /boot/cmdline.txt

Then, replace “console=tty1” with “console=tty3”. This redirects boot messages to tty3.

Remove other things

Still in “/boot/cmdline.txt”, add below at the end of the line

splash quiet plymouth.ignore-serial-consoles logo.nologo vt.global_cursor_default=0

Here are brief explanations.

‘splash’ : enables splash image

‘quiet’ : disable boot message texts

‘plymouth.ignore-serial-consoles’ : not sure about this but seems it’s required when use Plymouth.

‘logo.nologo’ : removes Raspberry Pi logo in top left corner.

‘vt.global_cursor_default=0’ : removes blinking cursor.

Note : The first three should be there by default, but make sure if those exist.

Creating the illusion that you're really in front of an old television

I searched on Youtube and found some videos with the boot sequence of an old TV with CRT tube. The example I used was this one: https://www.youtube.com/watch?v=V-nbvAnq65I

I downloaded the video using the excellent Youtube-dl tool

youtube-dl https://www.youtube.com/watch?v=V-nbvAnq65I

So I cut the end of the video, in the part where the TV is turned off, using Vegas Movie Studio edit tool in my Windows Computer.

I rendered the new video and saved as boot.mp4 in folder /home/pi in my Raspberry Pi SD Card.

So I created a new file as root:

sudo nano /etc/systemd/system/splash.service

I've used the following service file definition to kick off a slide show display early in the boot process with debian:

[Unit]
Description=Splash screen
DefaultDependencies=no
After=local-fs.target

[Service]
ExecStart=/usr/bin/omxplayer -b /home/pi/boot.mp4
StandardInput=tty
StandardOutput=tty

[Install]
WantedBy=sysinit.target

Following this instructions: https://raspberrypi.stackexchange.com/questions/48084/custom-splash-screen-video

Using the rotary selector switch to choose channels

The trick of this project is precisely this: use a rotary selector key to make the selection of different videos. The switch I used in the design had two poles and four positions. Any rotary key of #poles and # positions should serve. We will use only 1 pole and connect this pole to any GND pin on the Raspberry Pi.

Then, I use this Python Script:

#!/usr/bin/env python
import RPi.GPIO as GPIO
import sys
import os

from subprocess import Popen
GPIO.setmode (GPIO.BCM)

GPIO.setup(17, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(27, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_UP)

movie1 = ("/home/pi/Videos/Movie1.mp4")
movie2 = ("/home/pi/Videos/Movie2.mp4")
movie3 = ("/home/pi/Videos/Movie3.mp4")
movie4 = ("/home/pi/Videos/Movie4.mp4")

last_state1 = True
last_state2 = True
last_state3 = True
last_state4 = True

input_state1 = True
input_state2 = True
input_state3 = True
input_state4 = True

args = '-b --aspect-mode fill --win "0,0,1279,1023"'

quit_video = True
player = False

while True:
    #Read states of inputs
    input_state1 = GPIO.input(17)
    input_state2 = GPIO.input(27)
    input_state3 = GPIO.input(22)
    input_state4 = GPIO.input(23)

    quite_video = GPIO.input(24) # shutdown system

    #If GPIO(17) is shorted to ground
    if input_state1 != last_state1:
        if (player and not input_state1):
            os.system('killall omxplayer.bin')
            omxc = Popen(['omxplayer', args, movie1])
            player = True
        elif not input_state1:
            omxc = Popen(['omxplayer', args, movie1])
            player = True
    
    #If GPIO(27) is shorted to ground
    elif input_state2 != last_state2:
        if (player and not input_state2):
            os.system('killall omxplayer.bin')
            omxc = Popen(['omxplayer', args, movie2])
            player = True
        elif not input_state2:
            omxc = Popen(['omxplayer', args, movie2])
            player = True

    #If GPIO(22) is shorted to ground
    elif input_state3 != last_state3:
        if (player and not input_state3):
            os.system('killall omxplayer.bin')
            omxc = Popen(['omxplayer', args, movie3])
            player = True
        elif not input_state3:
            omxc = Popen(['omxplayer', args, movie3])
            player = True
            
    #If GPIO(23) is shorted to ground
    elif input_state4 != last_state4:
        if (player and not input_state4):
            os.system('killall omxplayer.bin')
            omxc = Popen(['omxplayer', args, movie4])
            player = True
        elif not input_state4:
            omxc = Popen(['omxplayer', args, movie4])
            player = True
            

    #If omxplayer is running and GPIO(17) and GPIO(18) are NOT shorted to ground
    elif (player and input_state1 and input_state2 and input_state3 and input_state4):
        os.system('killall omxplayer.bin')
        player = False

    #GPIO(24) to close omxplayer manually - used during debug
    if quit_video == False:
        os.system('killall omxplayer.bin')
        os.system('poweroff')
        player = False

    #Set last_input states
    last_state1 = input_state1
    last_state2 = input_state2
    last_state3 = input_state3
    last_state4 = input_state4

Saving the file as televisao.py in /home/pi/

Saving and converting videos

All videos have been resized to 1280 x 1024 resolution because the monitor used is at 5:4 aspect ratio (it's an old 17-inch monitor from LG). This was the most efficient solution because, for some reason, I couldn't get omxplayer to resize the videos correctly and the display was left with undesirable black bars.

All videos must be saved in the same folder as they were specified in the file televisao.py (in my case /home/pi/Videos). If you want, you can save the file boot.mp4 in same folder. Just remember to change the file location in /etc/systemd/system/splash.service.

Executing televisao.py at boot

Just as we created the service to display the video on boot, we'll create a service to run the python script.

I just follow this: https://learn.sparkfun.com/tutorials/how-to-run-a-raspberry-pi-program-on-startup#method-3-systemd

sudo systemctl --force --full edit televisao.service

And then, we write this:

[Unit]
Description=Show Retro Television
After=multi-user.target

[Service]
ExecStart=/usr/bin/python3 /home/pi/televisao.py

[Install]
WantedBy=multi-user.target

Enable and monitor the service with:

sudo systemctl enable --now televisao.service
systemctl status televisao.service

Reboot and see the magic happens!!!

Aesthetics

To give the illusion of an old TV, I created several layers in MDF and laser cutting, using Inkscape, with the exact measurements of the fresnel lens that I found in my scraps. The selector switch received a dial with VHF channels recorded in low relief. In the rehearsal video of the play we do not see this dial, because it was under maintenance. But in the final version, he was there. The system shutdown button went disguised as the brightness adjustment of the TV. All elements were painted with variations of black, silver and brown, to match the televisions of the 80s.

As soon as the video of the play is available I will share the link here. My wife and I produced several videos with making-off of the various objects of the piece and probably the ones in English to facilitate the understanding of non-Brazilians.