Moz-extension entry in Firefox history

Recently I noticed an odd thing appearing in my Firefox history. Whenever I would first start the browser, a line would appear in history:


A search yielded no result. I did find one discussion about a similar case where an add-on (extension) was causing this. I did other searches based on just “moz-extension” and “blank.html”. Eventually, I disabled a handful of add-ons and restarted Firefox. No odd entry! One by one I enabled them until I found the one that causes this entry:


I am writing to them to see if they know why this is happening.

Android g900vvru2dpf4 update, no Linux connect

After I upgraded to the latest Android g900vvru2dpf4 software, it no longer wants to show any files when I connect via USB to my PC. Tried reconnecting physically several times. No joy. I’ll keep messing with it in case I missed something.

EDIT: Had to go into developer mode and change USB setting from charge to connect. It will still charge but now the computer sees it as a device and can connect.

Form colors in Firefox 46

When I updated Firefox to 46, I noticed that something odd happened. The browser now had an odd brown/gray color and some forms (like on Yahoo news) had white text on a white background. I had recently used an addon called Stylish that allows the colors for certain websites to be changed, which I had done for the bright white of Google, changing it to a darker theme. But after the upgrade, Firefox continually had a dark upper menu area and the forms on Yahoo had white text. I even removed the Stylish addon, but the changes remained.

The most pressing part was the form text color. It made them basically unusable. One person suggested using a CSS file, and I tried that and it worked once and then not. No idea why it stopped. But Firefox has its own way to set form text colors, and that always works.

In the about:config page, I typed in browser.display to see the various options. These are the ones I set:

browser.display.focus_background_color;#FFFFFF (sets form background to white)
browser.display.focus_text_color;#000000 (sets the text color to black)
browser.display.use_focus_colors;true (tells Firefox to use the colors I specify)

The effect is immediate.

I gotta go, someone is wrong on the Internet…🙂

Update: As of FF 47, all the coloring returned to normal.

Nurse call station replacement

I was asked to repair or replace an old nurse-call station in a medical room. The current device was discontinued back in the 1980s (Rauland PCS-7351A), but has been working fine until the pull-string was pulled too forcefully. The purpose of the unit is simple: If a patient needs help, pull the string and a switch clicks and turns on a light and buzzer in the nurse station corresponding to the room number of the patient. A light on the switch also illuminates, indicating that it is working.

Rauland PCS-7351A 1

I took it out of the wall and realized that I had already repaired this unit once before, and it was likely going to break again. So I went online to see if I could find a replacement. I found a variety of call stations from various vendors that said they were equivalent. I finally settled on a suitable model and bought it. I knew the biggest challenge would be getting the back wiring correct. Since nobody who installed the original system had labeled anything, I had to guess at the purpose of some of the wiring.


Happily, the new unit came with a diagram that should give a 1-for-1 idea of where the wires should go. But I noticed a difference in how the old one was wired compared with the diagram. I guessed that it was simply a slight difference and made up my own diagram to take with me to the room.



I hooked it up according to my handwritten diagram and it worked! Happy camper. The new unit is a much simpler toggle design than the old one. Time will tell whether it will withstand use and abuse. The most obvious flaw I saw was the simple nut on the face plate that keeps the switch in place on the new unit. A disturbed patient could unscrew that, push the switch into the cavity and cause a repair call, though the switch would probably still work.

old unit

new unit

If it turns out to be a problem, I may have to find a smooth surfaced unit to replace it. I did see one such unit in service in the same ward, but haven’t had time to examine the wiring. This is the Rauland PBS113, also discontinued, though we have a spare or two. No idea what the various wires do, and no diagram to help this time. However, an old tech at Rauland kindly sent me a PDF with text that describes which wire goes where on a call station, and that will prove useful.

Rauland PBS113


I did find a waterproof (WP on the diagram) design by Crest that uses a magnetic reed switch. I am guessing at the wiring, and show it here as a possible solution since I haven’t had a chance to try it yet.



Static or electronic noise with mic input on PC

I was trying to record a vocal track on my computer using Audacity, but kept hearing an odd chirping hiss in the background. I did some digging and found that for several years people have been having trouble with the Realtek ALC889 and related audio chipset and Linux. There are a variety of work-arounds, and none worked for me. I even booted into Windows 7 and heard the same electronic buzzing in the background. This led me to look at a hardware solution instead of a driver nuance.

My microphone is connected to a Mackie ProFX8 v2 mixer and then the board feeds out of the mains to the microphone plug on the front of my PC. Any wiggling of the connection going into the PC led to more pronounced electronic buzzing. That seems to be the weak link. I recalled that this mixer board has a USB interface also, so I hooked that up and disconnected the PC’s mic input. I checked in System, Preferences, Sound, Input and saw that the input device was now listed as “Analog Input PCM2903B Audio CODEC”.

I went into Audacity and looked on the input devices, and this was not shown. Hmmmm. I went ahead and left the input set to “default: Front Mic:0” and hit record. It worked, and with no background noise at all. This is great, because now I can have multiple mics and sound coming through the mixer board with reverb and pipe it all through the USB connection.

You may need to set levels using the alsamixer command.

Here are some things I have discovered about this setup. Mackie doesn’t really document the USB output very well at all. It can be an input or an output without any sort of switch, apparently. There is NO volume control for the USB output.

I’m using the following configuration:
Mic is on XLR 1. Gain is set to nearly full. Slider is set to U.

USB connection from board to computer USB
(NOTE: output from the USB port is not related to the MAIN slider at all, but to the mic gain and slider. MAIN slider controls output to the MAIN Out and to XLR out on the back, I think. USB Thru button has no effect on USB output, nor does the knob USB Input Level.)

The only way I can increase or decrease mic volume is via mic gain or slider. No other volume control seems to affect the USB output on this board.

Just for kicks I did try the Main Out with an unbalanced dual 1/4-inch to stereo 3.5mm to my computer’s mic input. I got so much noise in the background that it was useless.

I also recorded using the Main Out to a handheld Sony digital voice recorder ICD-AX412 and it sounded very good indeed.

This leads me to conclude that the computer audio hardware is at fault. (ASUS P6X58D Premium motherboard with built-in audio). I’ll have to look into an add-on card from Soundblaster or other.


Foam Windscreen On Microphone Or Not? (Audio Geekery)

I am a jazz singer in my spare time, and have been talking mics with various musicians. There is a sharp division between those that think the foam “clown nose” on a mic is a good idea or a bad idea.

I perused several Internet forums and there are endless discussions of what people think and feel it does to audio quality, and how well it stifles sibilance (the “essss” sound) and plosives (the popping sound of B, G, T, and P consonants). Some simply don’t like the appearance with the foam cover. Others feel it is important for keeping spittle out of the mic, especially if it is used by other singers. Much easier to clean the foam cover than get crud out of the mic itself. And keeping the foam clean is stressed, since a dirty cover will stifle sound quality.

Some feel it ruins the sound entirely, some feel it cuts off too much of the high end, some say it cuts of just a tiny bit of the high end while doing a great job of making the singer sound like he or she isn’t using a mic.

Lots and lots of theory and emotion are bounced around, but even when they talk about testing the differences, I don’t see them published. So I decided to do my own tests by recording the mic with and without foam, singing, purposefully using plosives and sibilance, and then speaking normally. I don’t have the equipment to do graphs of frequencies, so my tests were subjective. And that is ok. I was not going in with preconceived notions of what it will do besides reducing “wind” sounds. And cutting off a tiny bit of the high end is intentional when using the foam, since that is where sibilance happens.

I recorded a variety of my singing and speaking using Audacity, comparing similar lines with and without the foam cover. I also varied the distance from the mic and the amount of gain on the mixer. I’m comparing my mic with a friend’s mic I have used previously.

I’ll tell you right up front that it depends on the microphone. I’ve used a few different mics, and own a Heil PR-35, a dynamic mic with a large diaphragm. I have a friend who uses the Shure Beta 58a for doing regular gigs. On her mic, I sound really clear with no foam cover, and the sibilance and plosives are minimal even when I’m up on the mic where the richness of my voice comes through the best.

On my mic (Heil) with no foam cover, I have to carefully control my speech to avoid over-popping P’s, and the sibilance is easy to hear (a common complaint with the sensitivity of this mic). However, when I add the foam cover to my mic, most of those issues disappear. I do lose some volume which can be easily adjusted on the mixer. But unless I were switching back and forth between foam and no-foam, that wouldn’t be an issue. I would simply do the mic check with the foam on and go from there. I didn’t really notice a quality of sound change except at the far high end. Another thing I noticed was that my mic picks up more volume by the nature of the larger diaphragm size, so I also had to adjust the volume down on the mixer to compensate for the difference between the two mics.

Some forums advise backing away from the mic overall to control plosives, and cranking the gain to compensate. I found that this led to a more tinny sound unless I was doing full-voiced singing (and I’m often doing much more intimate singing styles). I did comparisons of foam and no-foam at 8-10 inches and found that plosives were still an issue with no-foam.

I found that being right up near the Heil PR-35 WITH the foam cover yields the best result with the this mic. I have to keep the gain on the mic down because I’m so close to the mic, but I get a richer sounding bass quality when I’m up close. But again, that is with THIS mic. With the Shure, I didn’t need a foam cover for sibilance and plosives. The EQ can also be adjusted a bit to add in more mid and high range if you feel the sound quality has changed.

I still need to do a test between the two mics to hear which I like better with my voice. And that is the best approach to buying a mic for yourself. Test them at a local music store doing the style of singing you do. Some mics pick up bass better, but if you are a soprano, you are more interested in a clear high range. Having a good matching mic is one of the most profound changes you can make to your singing, as is a quality sound system (and knowing what the knobs do to your sound).

Doing some side-by-side comparison, my friend said the foam made my voice sound muddy compared to no foam, so we removed the foam, adjusted the mic gain down, and it sounded fine with my lips about 3-inches from the mic.

Fluoresence of semen (forensics geekery)

After hearing in the news that a blacklight can be used at a motel to check for semen stains on sheets and carpets, I began experimenting with that concept to see if it is at all useful (ok, I’ll wait for you to stop laughing… This is science, people!).

TL;DR: What I found is that a typical blacklight is entirely useless for detecting semen, but does cause urine, cat vomit, some soda pop, some drugs, and soap remnants to fluoresce. Several fabrics and papers are infused with whiteners from detergent or mixed into the fibers, and these will also fluoresce brightly. Liquids spilled onto such fabrics or papers may draw out these whiteners and seem to fluoresce, but it is a secondary effect rather than the liquid itself. Key point: UV is only useful to help find droplets during an investigation. It doesn’t identify what the substance is.

Semen will very slightly fluoresce blue under some lights, and orange under other light. Wet semen does not seem to fluoresce at all, it must have dried. (1)

A bit of background on fluorescence
Our eyes can seen the “visible spectrum” of light, from about 400nm (nanometers) to 700nm. The typical blacklight has a predominantly ultraviolet (UV) wavelength of about 360-370nm, which is also called “longwave” ultraviolet. The bulbs are usually coated with a dark blue filter to keep most visible light from emitting, though there is always a dark violet glow. This coating leads to the industry term of “blacklight blue” or BLB. The non-coated bulbs (BL) emit a bright blue glow in addition to the UV and are used more for bug-zappers and for killing bacteria.

Fluorescence of a material is based on the wavelengths of light it absorbs, and the wavelengths of light it emits after absorbing light. We tend to notice fluorescence most when the source light is low in the visible spectrum (such as a black light), coupled with fluorescent material that emits strongly in the visible spectrum (like highlighter pens and blacklight posters). Most fluorescent minerals require an ultraviolet source wavelength that is “short” (250nm to 300nm), which is dangerous to our eyes and skin, and requires the use of UV filter glasses to safely use. Minerals will typically not fluoresce at all under a standard blacklight. The total UV light spectrum starts at the extreme end of 10nm wavelength and stops around 400nm.

The source light wavelength that causes fluorescence of semen is reported to be 415-490nm, which is not UV at all, but is in the visible violet-blue-dark green part of the spectrum. The best wavelength was 415nm according to one source (1), but another claimed that 570nm (light green) was useful without any goggles (3). The fluorescent emission peaks of semen are reported to be around 460-520 nm, though one older paper specifically mentions 622nm emission when excited with 488nm (2). Blue LEDs are sold in the 450 to 480nm range, and filters are also sold for that range. Some forensics websites are now selling blue LED flashlights for this purpose. But because there is so much visible light produced by these lights, they recommend using dark orange glasses to filter out the blue light and let the fluorescence come through.

My approach
Since the light sources used in forensics are priced so highly (due to selling to law enforcement, and the intense mercury vapor or argon laser light source), I began to experiment with lower cost solutions. Perhaps I could substitute “blu-blocker” sunglasses and use a light source I already had. The GoLite P2 for winter light therapy is said to put out about a 470nm blue light which is in the right range for a source light.

I did a lot of searching online and found a cheap blue-LED flashlight in the 455-460nm range (LED Wholesalers B001TIEHO2), and some dark orange safety glasses (UVEX S0360X) on Amazon. (insert pic) The dark orange glasses filter out the visible blue light from the flashlight, but allow the fluorescent emission of certain materials to pass through. I also bought a 56-inch square piece of orange colored transparent vinyl, with the idea that I could make it as dark orange as I like. However, though it is “transparent”, it is not optically clear so it isn’t that great for seeing clearly.
blue and orange - amazon

Results of the blue/orange approach
With this combination, I found that I could still see urine and soap (and cat vomit traces on the rug) very brightly and with good contrast. But semen still was nearly invisible. I still need to try mucus and blood.



I have no way to verify if the LEDs on my flashlight are actually in the correct spectrum, and am relying on the manufacturer’s description to be accurate.

Another issue is that the orange UVEX glasses themselves fluoresce, causing considerable fogging when the blue light is reflected off a white surface. Not sure if it is the plastic or the orange coloring that does this. A vinyl sheet that is clear didn’t fluoresce, but the orange vinyl did, so I’m assuming that it is the orange coloring that is used for plastics that is fluorescing rather than the plastic.

The Green Light approach (3)
My next experiment was to use a light-green filter over my regular CREE LED flashlight, to limit the output to the 570nm range.

I used a $5 filter advertised as a 570nm green filter, purchased from an online electronics company.

This approach is supposed to be used without goggles. I cut a square of aluminum foil and put a hole in the middle, and used clear tape to attach it. I placed this over the front of an Olight M22 Warrior flashlight on maximum output.

Well, that was disappointing. No fluorescence, no distinguishing characteristics at all for samples on wood and plastic. I didn’t pay to read the whole paper on this claim, so perhaps I missed something. I kinda doubt it though. Most examples of semen fluorescence are minimal even with advanced light filtration.

My conclusion is that semen is not particularly fluorescent.

You will definitely NOT find semen using a regular blacklight. A blacklight is useful for finding traces of soda-pop, urine, vomit, and several items listed below. The blue-light with orange goggles is the best overall for finding urine and such, as it really pops out brightly.

Remember that in the forensics field, fluorescence only helps locate samples of semen, not to identify it as a particular substance. Identification is the realm of chemical and microscopic analysis. In the quote below, it is said to be highly presumptive to do otherwise. This is because so many kinds of stains (soda-pop, urine, soap, vomit, and lots more) will all fluoresce, and far more brightly than semen.

Other things that glow brightly under a regular blacklight:

      Tonic water (quinine makes it glow bluish) and several soft drinks with bright colors.


      The many zillions of brightly dyed candies, and spit/drool containing dyes from pop or candy.


      Scorpions (good way to locate them at night) and some other arthropods




      Many plastics


      paper dust, certain kinds of cloth dust


      According to one website, some narcotics[4] (again, only an way to locate, not a positive ID):

Cocaine (UV flashlights are used to detect this in the nostril region)
MDMA tablets (including some but not all Ecstasy tablets)

Cocaine – Cocaine having a purity of at least 87 % fluoresces clearly when illuminated with UV light.

Amphetamine – Some amphetamine having a purity of 78 % are clearly fluorescent when illuminated with UV light. Even small amounts of amphetamine are easy detectable because of their fluorescent nature.

MDMA tablets – Some MDMA tablets (i.e. Ecstasy with four-leaf clover logotypes) are clearly fluorescent with UV. Even small fragments are easily visible as they fluoresce intensely.

…semen will fluorescence due to the presence of molecules such as Flavin and Choline-conjugated proteins. The color of this fluorescence will vary from blue to yellow, depending on the light equipment used. There are many molecules (natural and artificial) that will fluoresce in a similar way as semen, and therefore, this detection technique is highly presumptive. Furthermore, not all semen stains will fluoresce under such specialized lights. Exposure of the sample to factors such as heat, humidity, oxidizing agents, and microorganisms such as bacteria and mold can affect this fluorescent activity. Semen fluorescence can also be masked by certain types of fabrics and fabric treatments. Hilton J. Kobux, D.Phil., Edmund Silenieks, and Jordana Scharnberg, B.Sc., Improving the Effectiveness of Fluorescence for the Detection of Semen Stains on Fabrics, 47 Journal of Forensic Sciences 4 (2002); S. Marshall, A. Bennett, and Dr. H. Fraval, Locating Semen on Live Skin Using Visible Fluorescence, Rofin Australia Pty Ltd. (2001).

…if you illuminate dry semen with a band of light around 350 nm HPBW 40 nm (ie 330-370 nm), which is invisible to the human eye, then the semen will fluoresce, into the blue visible region (ref trace 2). The advantage of this is that you can make invisible semen stains appear visible to the naked eye…
there is an alternative to using UV when searching for semen stains. Illuminating dried semen with a band of light around 450 nm HPBW 40 nm (ie 430-470 nm) will produce strong orange fluorescence (ref trace 3) in a broad region with a maximum around 520 nm.

Best results were found with 415nm excitation (source light) and a 475nm high pass filter. Light appears greenish, semen shows up bluish.
2nd best was 450nm excitation with 590nm high pass filter. Light appears orange, semen appears yellow-orange.
Source light in both cases was Polilight Bluescan.