Print PDF
Favorite
Email
Step 2DDC is I2C
When I said in the introduction that there's no external I2C port on most computers, I lied. Turns out there is, and it's been there all along for nearly a decade now, mostly sitting dormant.
Most modern graphics cards and monitors have support for something called Display Data Channel (DDC), a communication link within a video cable that allows the computer and display to negotiate mutually compatible resolutions and permit software control of monitor functions normally accessed with physical buttons on the display.
DDC is, in fact, simply an implementation of an I2C bus with a few established rules. By tapping into this connection between the computer and monitor (or making use of the DDC lines on an spare unused video port, such as the external monitor connection on a laptop), one can interface with some I2C devices at virtually no expense, bypassing the usual need for an adapter device entirely.
All we need to physically access this I2C bus is a hacked-up video cable...
Most modern graphics cards and monitors have support for something called Display Data Channel (DDC), a communication link within a video cable that allows the computer and display to negotiate mutually compatible resolutions and permit software control of monitor functions normally accessed with physical buttons on the display.
DDC is, in fact, simply an implementation of an I2C bus with a few established rules. By tapping into this connection between the computer and monitor (or making use of the DDC lines on an spare unused video port, such as the external monitor connection on a laptop), one can interface with some I2C devices at virtually no expense, bypassing the usual need for an adapter device entirely.
All we need to physically access this I2C bus is a hacked-up video cable...
| « Previous Step | Download PDFView All Steps | Next Step » |
 |
Add Comment
|
