More Peeping

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.

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.

Spring Peepers

Spring Romance

Something New/Old

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

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.

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.

IPM Module Failure

After rebuilding using the other IPM module and additional FET's, we experienced a second very loud failure as seen in this short video. The camera runs at 15 fps and the explosive incident is only visible, very brightly, in one frame.

Extension Assembly for IPM Module

To facilitate repair and testing, we've turned the heat-sink/IPM module on its side, added another heat-sink on top for external FETs, and temporarily mounted this to the Y sustain board. During testing, we encountered a failure (visible short on die) in one FET on the remaining healthy IPM module. We are now hand wiring high power discrete FETs (two seen on the left in this photo) taken from the other TV externally to substitute for the on-module devices. In one test, we experienced a very loud and spark-filled explosive failure destroying the remaining on-board FETs, some surface mount resistors, and the external FETs. We've rebuilt this assembly with the other IPM module and additional high power FETs; test results shortly....