Thursday, April 30, 2009

Wednesday, April 29, 2009

iButton Water Temperature Test


The iButton inside the brass chamber was suspended from a tree branch just below the surface of the Peeper swamp for 48 hours starting at 8pm. The following day, it was very warm with the air temperature rising above 90 degrees. Both the night before and night after were much cooler as was the second day. Temperature sample rate was 5 min/sample (horizontal scale is 5 minutes/tick mark). Information about iButtons is available by clicking on the title of this post which links to the Maxim-IC site.

Monday, April 27, 2009

iButton Deep Water Chamber

This is a simple brass chamber containing a temperature recording iButton mounted on a foam-core insert. The orange tape indicates the end most tightly secured; both Teflon tape and heavy rubber gaskets internally are used. Tonight, we suspended it just beneath the water surface in the swampy area behind our house with the device set to take temperature samples every 5 minutes.

Spring Peeper Call


This is a spectral analysis of a recording we made tonight of a spring peeper. The fundamental or dominant frequency is consistently near 3200Hz. The male calls as loudly as possible at this pitch to attract a mate. Distinct harmonics are seen at 2x (6400Hz) and 3x (9600Hz) with overtones spaced evenly between at 1.5, 2.5, etc. Audacity is the audio tool used for presentation and analysis.

Saturday, April 25, 2009

Spring Peepers


Spring Romance

Something New/Old

With tourism down, new attractions can often help....

Sunday, April 5, 2009

Light Box


A great light box built from a CCFL back light extracted from an old LCD display. Exceptionally uniform light intensity distribution across the entire surface. The colored squares are filters. It runs on +12vdc (2amps) & + 5vdc.

Thursday, April 2, 2009

New Speaker Design


Snapshot of work in progress on new speakers. Intended as platform to test speakers, enclosures, ports, cross-over networks, filters, and amplifier designs.