Saturday, September 13, 2008

Tuner power consumption

Tired of using a meat thermometer to look for power problems, I borrowed Brendan's meter, cut up a USB cable, and built a rig to measure USB power consumption (my meter died and my old man's is MIA somewhere in a New Jersey basement). A 6" USB extension cable, a couple of banana connectors, some hookup wire, and viola!

Amazing though how your whole afternoon can get screwed up by a lack of 2 inches of heat shrink tubing. I had to run around Manhattan because it turns up I ran out and didn't realize it.

It's all working now. Some observations:
  • My Pinnacle PCTV HD Pro 801e consumes about 120ma at idle, and goes to 320 at digital capture.
  • The power consumption doesn't fall back to 120ma after I stop capture (suggesting the device is not being put back to sleep properly)
  • My Pinnacle PCTV HD Pro using em28xx consume 520ma both at idle and at capture. That's not good and suggests I might have both the lgdt3303 demodulator and the tvp5150 enabled at the same time.
Now that I have the rig setup, I should be able to quantitatively compare the devices at capture versus idle for both analog and digital, as well as comparing Linux versus Windows. Pretty cool.