This is a work-in-progress… Run compiled Matlab applications or components without installing Matlab. Download and install the Windows version of the MATLAB Runtime for R2023a from the following link on the MathWorks website: https://www.mathworks.com/products/compiler/mcr/index.html (right mouse click, open link in … Continue reading
Matlab App Designer Listbox Index
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Matlab’s App Designer’s listbox lacks some of functionality of GUIDE’s listbox. App Designer’s listbox currently offers no direct method to obtain the index number of a selected item. Here is a roundabout method for a sample listbox named listbox_type: There … Continue reading
Carrier Air Conditioner Beat Frequency
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The top image is the air conditioner mounted near a back corner of my home. It is Carrier model 24AHA424A003. It has a scroll compressor, model ZP20K6E-PFV-130. I measured its output sound using my Android Smartphone. The condenser motor nominal … Continue reading
Jet Aircraft Takeoff Acoustics from Ground Measurement
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This gallery contains 4 photos.
I made a video using my Android Smartphone of this aircraft taking off from SeaTac airport, headed northward. The image above was extracted from the video. The date was July 20, 11:50 AM. This was Delta flight 1172 headed to … Continue reading
MV Chetzemoka Ferry Acoustics
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This gallery contains 6 photos.
MV Chetzemoka Ferry Air Vent Pipes I recently rode on the MV Chetzemoka Ferry which was running between Tacoma’s Port Defiance and Vashon Island’s Tahlequah terminal. The ship is powered by a pair of EMD 12-710 diesel engines rated at … Continue reading
Matlab Butterworth High Pass Filter, 6th order
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Matlab’s built-in function for Butterworth filtering has stability issues. The following code snippet yields an unstable filter. The cutoff frequency is 4 Hz. The sample rate is 20000 Hz. The filter is a high pass, sixth order. fh=4;sr=20000;order=6;Wn=fh/(sr/2);[bb,aa] = butter(order,Wn,’high’);flag … Continue reading
De Havilland Canada DHC-3 Seaplane Acoustics
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The aircraft is a De Havilland Canada DHC-3 Otter, Single Engine, Seaplane. It is powered by a Pratt & Whitney R-1340 Wasp, 600 hp, air cooled, radial engine with a propeller hub speed of 2250 rpm (35.7 Hz). This aircraft … Continue reading
Spring-Action Teeter Totter Natural Frequency
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Teeter-Totter, Playground along Riverview Blvd, Kent, Washington State I gave the teeter-totter an initial displacement, without human riders, and recorded the damped sine oscillation with my Android smartphone accelerometer app. The natural frequency was 2.1 Hz with 0.6% damping. The … Continue reading
Duwamish River Wooden Footbridge, Tukwila, Washington State
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This rustic bridge is popular with fishermen during the Salmon season from Summer through Fall. The Duwamish supports chinook, coho, chum and steelhead, as well as the more rare sockeye, sea-run cutthroat trout and bull trout. Pink salmon run in … Continue reading
Goodtime III Sound & Vibration
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My family and I recently took the Argosy Lock Cruise from Lake Union, through the Hiram M. Chittenden Locks, to the Seattle Waterfront, aboard the Goodtime III. The ship’s main engines are Caterpillar 3408’s coupled with Twin Disc MG514 reduction … Continue reading