Tutorial: Video output from your Arduino

Create video output from your Arduino in chapter 35 of tutorials about the Arduino universe. The first chapter is here, the complete series is detailed here.

[Updated 10/01/2013]

In this chapter we will examine something different – the ability of our Arduino and compatible boards to create composite video output. In other words, displaying stuff from the Arduino on a TV. A lot of people were unaware of the ability to do this, however the process is very simple and not difficult to implement from a hardware perspective. Within this chapter we will learn to construct the minimum hardware required and demonstrate basic functions to get started.

To whet your appetite, here is a quick video demonstration of what is possible:

You can’t expect too much from a 16 MHz microcontroller without a video card… but the price is right, and with some imagination and the right functions you can do quite well. To make this happen we need to knock out some hardware of our own. Connection is very easy. First we need to locate three pins on our Arduino board. They will be used to output Sync, Video and also GND. For those with Arduino Uno/Freetronics Eleven etc Sync is digital 9, video is digital 7 and GND is … GND. If you have a Mega/Mega2560 Sync is digital 11 and video is A7. There is also the ability to generate audio with the methods in this article, and if you want to do this the Uno (etc.) pin is digital 11 or 10 on the Mega.

The monitor or television used needs to have a composite video-in socket (jack). For those with older televisions that have a VCR connected, you could use the video-in socket on the VCR. The schematic for video out is very simple, you only need two normal 0.25W resistors and a video lead:

If you’re not up for soldering into an RCA plug, a simple way is to chop up a standard video lead as such:

Then just wire the termination of the two resistors to the centre core (“pin”) and GND to the shield. For the purpose of this article I have made a quick TV-out shield that also includes a thumb joystick (as reviewed here).

A real triumph of engineering… however it solves the problem. The vertical trimmer is connected to A0;  the horizontal to A1; the button to digital 8 via a 10k0 pull-up resistor. Next, you will need to download and install the arduino-tvout library. It can be found here. We will use the TVoutBeta1.zip version.  Those of you who may have a nootropic design Hackvision – please note your library is different.

Now to see how to integrate TV-out into our sketch. We will run through the basic functions which integrated with your imagination should see some interesting results…  So let’s go!

For every project, place these two lines at the top of your sketch:

The first brings in the library, and the second line creates an instance of TV to use with the library functions. Next, we need to activate TVout and select the appropriate broadcast standard (PAL or NTSC). In void setup() use either

Now for the main functions. The first one of interest will be:

which … clears the screen. Or if you would like to fill the screen with white, use

Moving on – to write some text. First we need to select a font. There are three basic fonts to choose from:

  • font4x6 (each character being 4 pixels by 6 pixels, etc.)
  • font6x8
  • font8x8

Well there is four, but it wouldn’t display for me. Working on it! To choose a font use:

Then to write the text, choose the screen location with:

then display the text with:

You can also use TV.println(); to add a carriage return as expected. Display single characters with a position in the one function using:

So let’s have a look at the various fonts in action with the following sketch:

 

Now to move into the 1970s with some basic graphical functions. We have a screen resolution of 128 by 96 pixels to work with. When planning your display, you need to ensure that the sketch never attempts to display a pixel outside of the 128 x 96 screen area. Doing so generally causes the Arduino to reboot.

First let’s start with basic pixels. To draw a pixel, use:

where x and y are the coordinates of the pixel, and z is the colour (1 = white, 0 = black, 2 = inverse of current pixel’s colour). You want more than a pixel? How about a line:

Draws a line from x1, y1 to x2, y2 of colour colour. (1 = white, 0 = black, 2 = inverse of current pixel’s colour).

Rectangles? Easy:

Draws a rectangle with the top-left corner at x,y; width w, height h, colour and optional fill colour. Circles are just as simple:

Draws a circle with centre at x,y; radius r pixels, edge colour, optional fill colour.

Now to see these functions in action with the following sketch:

And for the video demonstration:

So there you have it, a start with Arduino and TV-out. Furthermore, a big thanks to http://code.google.com/u/mdmetzle/ for the arduino-tvout library.

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Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

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John Boxall

Founder, owner and managing editor of tronixstuff.com.

46 Responses to “Tutorial: Video output from your Arduino”

  1. Norman Elliott says:

    Hi John,

    Another great tutorial. I am just constantly amazed at what can be done with an arduino board.

    norman

    • John Boxall says:

      It never ends! Sorry it was a bit short, I ran out of time and wanted to get that article out before the end of the month. In a few weeks I will continue with another TV out article.
      cheers
      john

  2. hlantz says:

    Hello John, and again thank you for an inspiring series! On a very non-Arduino-related question, what is the music in the top and bottom clips. Shazam can’t match it, and I feel the urge to make an iTunes purchase!

  3. Tim says:

    Very cool! I hadn’t seen this library, and assumed that I’d need the Nootropic board to play with this type of thing. Thanks for the info!

  4. Jeff Gilmour says:

    Great tutorial as usual, John! Any ideas on the feasibility of color video with the Arduino? What would be the limiting factors? It’s just amazing what you can do with an Arduino and some programming.

  5. stpdxpdc says:

    very cool project using TV-out library..can u update this article with full schematic from the joystick?

  6. NateC says:

    hi, is it possible to run this in parallel with a compiste video feed to create a Onboard Screen Display where in the black areas would display live video feed and displaying changing information add by the arduino?

  7. Mark says:

    Hi John, excellent article! I was just wondering if it would be possible to isolate the arduino from the TV, maybe through an opto-isolator? Thanks.

  8. Spammer says:

    Can I just say what a relief to discover someone that truly knows what they’re talking about over the internet. You certainly understand how to bring an issue to light and make it important. More and more people must read this and understand this side of your story. It’s surprising you aren’t more popular because you certainly have the gift.

  9. SHOBHA says:

    hi just wanted to know whether tv out supports any timer ? when i use my arduino with video experimenter shield for display text on tv , the text will be displayed all the time…i want to display the text for certain time it self , like around 10minutes….does tv out library supports this kind of application?

  10. Jason Adams says:

    Hi John. cool article. do you know if tv library is compatible with 1.0 IDE?

    Regards
    Jason

  11. Kana says:

    Hello,
    I was wondering about the cable you are using, RCA Composite Video. I have a cord similar to it but when I cut open the inside, the core/pin is not solid but instead made up of many tiny copper wires. I tried using this anyway but my images display very shaky and not completely clear. Do you think it has to do with my cable or is it more likely to be an error with my circuitry? I have also seen that my Sync pin doesn’t affect the image whatsoever. Perhaps it is shaky because of this?
    Thank you.

    • John Boxall says:

      Yes, it does sound flaky. Double-check your circuit and wiring, and if possible try a different coax lead. Sometimes you can get a lead from a cheap $2 store – then cut the plug from one end and use that.
      cheers

      • kanaabe says:

        Thank you very much. I think the cable I have is not COAX. It is the yellow component of the Audio/Video cable. I will try to get a COAX cable and an RCA converter. Does that sound right? Also my TV is very old from the 90’s. Sorry I am new to this, this is my first Arduino project with Video! I found your tutorial very helpful though and it is my primary resource at this point!

      • John Boxall says:

        No, the yellow one is fine.

  12. Tim C says:

    Great Job John. Question – Is it possible to use the cable/antenna coax input instead of Video in (which I don’t have). Thanks

  13. Steve Black says:

    Hi, this is not “TV.draw_rectangle” is “TV.draw_rect” :)

  14. Steve Black says:

    Good tutorial ! Did you do a tutorial on the TV audio output? because I’ve created a little game and I would like to have sound !

  15. Heldur says:

    Hi!

    Nice going :)
    This solution is exactly what I need to simulate black-screen :) Thank you for that!
    One question:
    is it ok to “multiply” output for let’s say for 12 inputs with just using hex-buffers behind ouputs 7 and 9. Buffer inputs group together and connected to pin 7, another group to pin 9, and all “new” outputs in series with resistors like pins were at first? Or will there be some problems with this plan?
    Thank you!

    Heldur

  16. Steve Black says:

    Hello ! I found a library for displaying color on a screen with VGA output (https://code.google.com/p/arduino-vgaout/) but I can not find tutorials and that is why I ask you if you could make one? Thank you in advance! :)

  17. Jonius says:

    hello Jhon

    do you have a tutorial about accelerometer mma7361+arduino?

  18. Rodrigo says:

    Hello John!

    I wonder if it would be possible to superimpose characters in a video signal captured by a camera? Hug.

  19. Mike Stand says:

    Hello.

    Thanks for these tutorials! Your the best!!
    And have you idea why “TV.start_render(_NTSC)” line gives me error that says “error: ‘class TVout’ has no member named ‘Start_render'”

  20. joey mariano says:

    Will an arduino mini Atmega 328 work with this?

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