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The littorine snail in that kid’s knee

This news story about a seashore snail found living in a child’s knee wound has been making the rounds lately.

Apparently 4-year old Paul Franklin from Southern California was camping at a beach in central California near Morro Bay, when he fell and hurt his knee (Orange County Register). For several weeks afterwards, the wound refused to heal fully, despite the use of … Continue Reading

Stupid water bath tricks

As part of the downward spiral into increasingly esoteric subjects that is currently happening on this site, I now present some info on making a water bath do things. Simple things, but things nonetheless.

An old Cole-Parmer Digital Polystat water bath.

As part of an ongoing project in the lab, it became necessary to start carrying out simple temperature ramps with a water bath. For instance, we’ll start from a temperature of 15°C and go to a target temperature of 35°C at a … Continue Reading

O2 conversion

The molar volume of an ideal gas is ~22.4 liters per mole (we’ll  consider O2 to be an ideal gas for these purposes, and 22.4 is an approximation that varies with temperature, it’s 22.414 at 0C). Convert from 22.4 liters to milliliters ( = 22400 ml per mol). So if you have 1 milliliter of an ideal gas, there is 1 ml / 22400 ml per mol = 0.00004464 mol of that gas, which is 44.64 µmol of the gas. Thus, if you have a volume of a gas in ml, you can calculate the µmols of that gas simply … Continue Reading

Removing security features from a pdf

Whoops, I totally made my own pdf and accidentally included a bunch of security features, so now I can’t use my highlighter or type notes on the document. It sure would be handy to take off those security features that I put there myself when I made the pdf, myself.

With a full copy of Adobe Acrobat and the associated Acrobat Distiller software, the process is as follows:

1. Open the secured pdf in Acrobat.

2. Go to File>Export>Postscript>Postscript and save a .ps version of the pdf file.

3. Open the .ps postscript file in a text editor (WordPad on Windows works fine).

ImageJ StartupMacros

Before I lose this file again: StartupMacros.txt This is a text file, based on the original StartupMacros.txt file that came with ImageJ, that can be dropped in the ImageJ/macros folder that is created when you install ImageJ. Start up ImageJ, and if this macro doesn’t automatically run, go to Plugins>Macros>Startup Macros to load it. It installs a few more drawing tools on the ImageJ toolbar and creates some keyboard shortcuts for the following tools:

• Line tool – press ‘l’
• Brush tool – press ‘b’
• Eraser tool – press ‘e’
• Wand tool – press ‘w’

I either found or created some code … Continue Reading

Adventures in kludgy software – Diving PAM edition

As a general rule, expensive pieces of lab equipment must come with software of questionable quality. In this case, I just want the raw data off a \$20,000 submersible DIVING-PAM fluorometer, which can be used for measuring the photosynthetic yield of algae and plants out in the field, away from a computer. But downloading the data requires a mini-odyssey through some needlessly confusing software that comes with the unit.

To start with, the packaged instruction manual for our DIVING-PAM still references a DOS-era utility for downloading the data, because the (brand new, delivered in 2012) instruction manual was printed in 1998. … Continue Reading

Waterproofing iButtons, and reading waterproofed iButtons

iButton temperature dataloggers are tiny, long-lived temperature sensors that are great for all kinds of environmental and biological monitoring, but they’re a long ways from waterproof. Old farts will regale you with tales of a bygone era when you could leave a bare iButton submerged in seawater for months at a time without problems, but those days are long gone, due to a re-design in the early 2000’s. Nowadays you can’t even get away with leaving them in moist soil without eventual water intrusion, component failure, and data loss. But given their tiny size and relatively low price … Continue Reading

Have some squid

You might be forgiven for thinking that the ocean is an endless bounty of edible goodies when you walk outside and find squid just strewn everywhere on the beach, waiting for you to pick them up and eat them. This happened the other day at work, when a group of juvenile Humboldt squid (Dosidicus gigas) decided to sun themselves on the beach. And then they died. And some seabirds got a good meal out of it. Enjoy some pictures and video.

ATtiny84 LED display and heater project

Here’s a little project that uses an ATtiny84 microcontroller, programmed with the Arduino software, to build a thermostatically-controlled heater. It allows the user to choose a temperature setpoint, and then displays the current temperature using an Adafruit 4-digit 7-segment LED display over I2C. The youtube video below demonstrates part of the project, where an ATtiny84 processor is used to drive the Adafruit display.

To get the project rolling, I installed the ATtiny core files available from High-Low Tech. The instructions there helped get the ATtiny84 running on a breadboard. I use … Continue Reading

USB extension cables

Here’s a standard USB webcam sitting on top of 30 meters of USB extension cables (three 10 meter cables). Three cables daisy chained together with the webcam attached to the end seems to be the functional limit. Adding a 4th 10-meter cable results in the camera not being recognized.

30 meters of cable powering a USB webcam, which is taking its self-portrait in the mirror.

These 10 meter extension cables, also called “repeater” cables, are available for around \$10 apiece. We’ve been using them to run a … Continue Reading