Code and hardware for simulate a channel change in a old tube TV.
The Raspberry Pi change a random movie file in the folder 'movies' when the TV is showing a static noise. The static noise is provide by the TV circuit. A Arduino Mini Pro get the voltage on the tunning potentiometer and turn a relay on or off, selecting the TV composite video input or the noise from the TV circuit.
WARNING: Dangerous voltage inside TV set! Be Careful!
- Demo Video
- TV set:
The TV set is a 5 inch tube TV with AM/FM radio. The set is powered by a 12V DC external power supply and has composite video and audio input. This input is selected by a switch on the back of the TV set. The TV has a battery compartment in the bottom where I mounted the Raspberry Pi.
The tuning circuit use a potentiometer to variable the voltage to the TV tunner. The radio board use a variable capacitor. The variable capacitor and the potentiometer are mechanically connected to the tunning knob.
-
Hardware Schematics:
-
Relay Board:
-
Level Shifter:
-
Regulator module:
-
-
TV modification:
- Remove the internal power supply transformer. The set will be powered by a 12V DC external power supply only.
- Remove the battery contacts for more room for the hardware in the battery compartment.
- Cut the tracks of the tuning potentiometer, isolated it and connect it to the Arduino board:
- Isolate the video/TV switch and connect the wires to the relay board:
- Get the 12V from the DC barrel connector.
All the wires are send to the battery compartment.
- Software:
- TVSim.ino = Scketch for Arduino Mini Pro.
- TVSim.py = Script for Raspberry Pi.
For enable the Raspberry Pi composite video output use the command:
$ sudo raspi-config
Put the Python script in auto start for the Raspberry Pi boot.
-
Hardware inside the battery compartment:
-
Known problems and items for future improvements:
- Sometimes the TV show the mouse cursor or the Linux terminal. (problem)
- Movies always starts from the beginning. (improvement)
- Different channels (scifi, horror, cartoons, etc...)(improvement)
