Video Overlay

Hulk

I formerly used a small circuit board (equipped with an SX, it could have been made by Bean or Hitt???) to genlock some alphanumeric characters on a security cam composite video. I had more camera applications and couldn't find any more of that circuit. Luckily, the Prop Backpack was released and worked extremely well for my overlay applications.
I just returned to the Parallax website and found that that part is no longer available. I expect that there is a way to use a Prop circuit to make/program the functional equivalent of the parts I used before. Does anybody know of an easy way to do a video overlay?

Duane Degn

I wonder if the video overlay circuit could be used on a separate board and then used with the Quickstart board or some other readily available Propeller board?

Here's the overlay section of the schematic.



There are two MOSFETs used in the circuit. Does anyone (Phil) have a Digikey or Mouser part number for a suitable MOSFET?

If I knew which parts to use, I'd layout a PCB and have a few boards made from OSHPark.

If/when I make a board, I'd certainly be willing to share the Gerber and/or Diptrace files to anyone interested in having their own boards made.

Is this sort of think Kosher? I think Phil did an amazing job designing the Propeller Backpack but if it's not available to purchase maybe it would be okay for some of us to use Phil's design in our own projects?

I have one Propeller Backpack myself but I'd like to use video overlay in multiple projects.

Phil Pilgrim (PhiPi)

The MOSFETs are a single-package dual nMOSFET. The part number is a Rohm UM6K1NTN. It is characterized for gate drives as low as 2.5V. This is important. If the chosen MOSFET requires too high a gage drive, it will not switch efficiently with the Prop. The MOSFETs are used for controlling the transparency of the overlain characters and their background.

I do have plans to reintroduce the Backpack as a full MoBo with onboard USB, assuming Parallax can be cajoled into carrying it. One more week of teaching, then summer (whee!), then back to Prop stuff (not teaching next year).

-Phil

Hulk

Duane, thanks for your considerable effort!
Phil, please sign me up if cajoling is successful! That board works miracles in FPV robots and my security cams and a hundred other video projects.

jtilghman

Phil,

I own a backpack and it is one of the neatest boards I have for my robots.

Please sign me up as well, if cajoling is successful!

MikeDYur

Duane and Phil, Sign me up as well, I recently purchased the MAX7456 and TSSOP breakout, but I would rather use another Propeller in my robot project.

Mike