Lawnmower Data, Excursions A and B

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[H2Dot] Data Sets

Five data sets were collected during these excursions. Exactly how the data sets were obtained is described in Provenance.

For each data set, the following table lists the model of sensor, the sensor's location on the specimen, the amplification, the sampling rate, and the names of the data sets in MATLAB and ASCII formats. The name of the data set will serve as a web link to further information, (plots, analyses), if such are available.

If you want to download any or all data sets, see Download Information.

Table of collected data.
Sensor Location Ampl (dB) Fs (MHz) MATLAB ASCII
A3 left, forwards 0 20 lmwr1_1 lmwr1_1a
A3 left, middle 0 20 lmwr1_2 lmwr1_2a
S9220 blue side down 0 20 scb scba
S9220 blue side down 0 2 scr scra
S9220 white side down 0 2 scg scga

[H2Dot] Provenance

We collected these sets of data on Monday 20 November 1995 and Monday 15 January 1996, respectively.

[H3Dot] Specimen

The specimen is a (brand???) lawnmower. The engine was running while we collected data. Estimated 1700 RPM, with a two-cylinder (?) engine.

[H3Dot] Equipment

We borrowed two Physical Acoustics A3 sensors and a Physical Acoustics S9220 sensor to collect these data. Sensors were attached to a LeCroy digital oscilloscope via BNC cables. No amplifiers or filters were used during this excursion.

[H4Dot] Sensor Mounting

The sensors were attached to the top of the lawnmower, (the blade guard), near the engine, using putty.

Data sets lmwr1_1 and lmwr1_2 were collected simultaneously, on channels 2 & 3, respectively. The transducer for channel 2, (lmwr1_1), was a little further towards the front of the lawnmower than was the transducer for channel3, (lmwr1_2).

Data sets scb, scg, and scr were collected sequentially, (one at a time).

[H4Dot]s Oscilloscope Settings

The LeCroy digital oscilloscope collected 1,000,002 samples/channel for each batch of data.

The vertical scale was 0.5 V/div for data sets lmwr1_1 and lmwr1_2. (With 8-bit ADCs, quantization step size is (8 div)*(0.5 V/div)/(2^8)=15.625 mV).

The vertical scale was 0.1 V/div for data sets scb, scr, and scg.

[H3Dot] Data Handling

Once the LeCroy digital oscilloscope had triggered, we transferred the data to 3-1/2" floppy diskettes. These were later converted to ASCII files using LeCroy's WAVE386 utility, and finally MATLAB converted the ASCII files into its own binary (*.mat) format.

[H2Dot] Download Information

To download any of this data, visit our ftp data archive. The data sets described in the above table are there, as compressed MATLAB or ASCII files. Click on any given filename, and your web browser should download the corresponding data set to your computer.

All of the data sets have been compressed using Info-Zip's zip utility. For a description of data formats, including links to free Info-Zip utilities, see Formats.

Experience suggests that Info-Zip compresses our MATLAB files by a factor of about 20:1, and ASCII files about 40:1. Keep this in mind when downloading data.