Tuesday, 30 July 2013

Arduino Video Overlay Shield

In 2011 I won a free pcb from Dangerous Prototypes, a Arduino shield you can use to overlay and display data on a video stream.

The Arduino Video Overlay Shield is based on the MAX7456 on screen display chip.
The Arduino compatible shield board overlays text on analog video, therefore
it allows easy overlay of text onto an analog video signal, NTSC or PAL.
Just plug it on an Arduino processor board to get started.
The shield is created by Lowvoltage Labs.

 I wanted to use it to display the subject line and address  of incoming emails while watching tv.
Another use could be a osd system to display flight data on rc planes.

Unfortunately the board needed a 27 Mhz crystal and I could not get my hands on one.
As soon I got one I could not find the board anymore,...
Meanwhile I found it and finally assembled it. The board worked out of the box, except the processors character set is Japanese by default! Luckily I could find a European standard Ascii character set and some code to upload it. The character set text file size is 170 kB and the upload took about three minutes.

Now the hello world output does not look so strange anymore.
A fine board and a interesting new chip, what could you possibly ask for more ?

One final but important note, do not forget to insulate the osd output plug, because it will most certainly short out on the Arduino Usb plug.

Osd shield ready for action
Osd shield top side
Osd shield bottom side, please do not forget the insulation on the video out side plug
Hello world test osd over webcam input

Dangerous Prototypes Video Shield Announcement
Lowvoltage Labs
Seeedstudio sells assembeled boards
MAX7456 datasheet
Wiki entry
Arduino forum thread


  1. Hi Michael,
    Nice job on the Video Overlay Shield build! If you need some extra parts like a crystal that fits I'd be happy to send you some. Drop me a line at http://lowvoltagelabs.com/contact/

    Eric (Low Voltage Labs)

    1. Hi Eric!

      Thank you for your compliments and kind offer, I know the crystal I use now is ugly as hell,...
      Btw. thank you for the free pcb!
      It was a hughe fun to build this circuit and learn more about this chip.
      Only the Japanes font was killing me, because I thought something is wrong with the chip (lol).
      I already found the correct crystal at Digikey and will buy one at my next order which will be very soon.

      Thank you!