I was wondering how much interest there would be for a shield board that could do video overlay using the Maxim IC MAX7456. I noticed that some software work has already been done with the chip on the Arduino.
I created a hardware design for a client using the MAX7456 chip in the past and found it to be a great chip to work with. I've started a schematic for a shield board and thought I'd get some feedback to see if it's something that people would be interested in purchasing?
If you would be interested in a video overlay shield board I'd love to know what sort of features you'd like to see on the board.
Here are a few features I've been thinking about:
- Multiple video inputs that could be switched between. This would allow the shield and Arduino to act like a video security switch. This could be a board stuff option?
- Jumper option to allow more than one video shield board to be stacked and controlled by the Arduino.
- Video input/output connectors: BNC or RCA?
- Any other ideas?
There was a thread from last year which discussed the MAX7456 and the original designer has reposted his files on his web site here
Recently I started doing a design were you had one MAX7456 per shield with a 74138 to provide chip selects so you could use up to 8x OSD shields with your Arduino but never got further than the first schematic draft
BNC would be my choice of connector, but RCA/Phono will work just as well and be cheaper.
Sparkfun have a breakout which I have bought. Note by default it is set to NTSC so europeans usually need to modify all code to display PAL instead. See the datasheet on sparkfuns site.
If I was thinking of additional features I would like on the breakout board would be
http://www.batsocks.co.uk/ type features such as serial rs232 input, stand alone type operation. listen on standard RX/TX ports for debug and monitoring of what is happening. (not using SPI lines or at least not affecting normal use of them)
Lots of sample code with PAL/NTSC define at the top.
Real time clock for time overlay or at least the ability to interface to another clock board from a standard arduino board.
Possibly a simple button to switch between 3 or 4 displays in memory.
Also a cool option would be an LED to show if SYNC detected from video source.
Software to use synce detected to trigger outputs etc for Amateur Television repeaters (E.g TV signal present, now change overlay text from testcard to timestamp and callsign in the corner and switch on relay etc)
or for security use when sync is not detected FLASH CAMERA FAIL in large writing and sound buzzer to warn operator.
I prefer RCA connectors.
The OSD is a bit limited in what it can do but possible sample graphics code to show graphs, boxes etc.
The board stuff option is the way to go for less common features, as long as it would be reasonable to solder (no SMD). If you want people to solder you need very large pads with good gaps between each pad.
The multiple board stacking option is good as many places need Camera1 lobby, camera 2 stairs etc. overlaid. Rather than a switched how about a 4 camera to one screen (1/4 screen each) chip before the text overlay?
Another big factor would be pricing vs sparkfun & batsocks board. Note batsocks board can be made with a standard arduino and a couple of resistors/diodes. It does not overlay. However once is is programmed it can't do anything else!