Battle with the raspberry - RC Groups
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This thread is privately moderated by Jack Crossfire, who may elect to delete unwanted replies.
Dec 04, 2012, 01:26 AM
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Battle with the raspberry

Its vision processing future looks bleak. With no preview video, it does a single 640x480 camera at 28fps. With preview video, it does 24fps. That's with it at 1Ghz, consuming 0.6A. Usage is evenly divided between JPEG decompression & blob detection.

The easiest solution is less resolution or downsampling to 640x240. 640x240 barely goes at 30fps with preview. 320x240 would be the maximum for stereo.

To get the CPU frequency in khz:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

To list the available governors:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

For comparing CPU usage of the different modes, fix it at the highest speed:

echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo 900000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

It does occasionally crash. It could be a flaky molex connector for power or the LM317 overheating. The servos aren't even being used, yet.
Last edited by Jack Crossfire; Dec 07, 2012 at 06:05 AM.
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