Noise Reduction Techniques for Your Shop-Vac

shop vac noise-reduction setup

Shop-Vacs are great tools, but they do have the notable disadvantage of being loud.  Fortunately, much of the noise emanates from the exhaust, and with a muffler or “silencer”, this can be controlled. The results of my noise-recustion experiments were noticeable, reducing the noise by roughly 5.6 decibels. This may not sound like a huge improvement, but since the scale is logarithmic the sound intensity is actually cut by roughly two-thirds, according to this calculator.

As for how to actually make the muffler, I’ve outlined everything in this post.  As of now, the Shop-Vac muffler is used in a static configuration, but with some changes it could be used on a mobile vacuum.  The disadvantage of this reduction in noise is a slight reduction in suction, but it seems to be an acceptable trade-off in this situation – used for a little CNC router with this adapter.

For a video of the Shop-Vac in action with the CNC router in question, check out the video after the break.  Note that this is pre-silencer, so you can definitely hear the vacuum noise! [Read more...]

Real-time depth smoothing for the Kinect

[Karl] set out to improve the depth image that the Kinect camera is able to feed into a computer. He’s come up with a pre-processing package which smooths the depth data in real-time.

There are a few problems here, one is that the Kinect has a fairly low resolution, it is also depth limited to a range of about 8 meters from the device (an issue we hadn’t considered when looking at Kinect-based mapping solutions). But the drawbacks of those shortcomings can be mitigated by improving the data that it does collect. [Karl's] approach is twofold: pixel filtering, and averaging of movement.

The pixel filtering works with the depth data to help clarify the outlines of objects. Weighted moving average is used to help reduce the amount of flickering areas rendered from frame to frame. [Karl] included a nice GUI with the code which lets you tweak the filter settings until they’re just right. See a demo of that interface in the clip after the break and let us know what you might use this for by leaving a comment.

[Read more...]