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2015-01-26 MightyOhm Geiger Counter Kit

One important reminder I should include is that radioactive materials and radiation can be hazardous to your health and high levels can cause deadly diseases such as cancer. The Geiger counter can tell when you are near radioactive substances but it does not tell you how dangerous the substance is. So even though this is not a toy, it could lead you to dangerous radiation without warning you of the danger. One example is that a radioactive dust particle could be inhaled or eaten and later cause cancer. The reader should take the proper precautions to prevent personal exposure.

I finally assembled the MightyOhm.com Geiger Counter kit that I got a week ago. It cost $100.00 not including shipping, from Adafruit.com, the Raspberry Pi guys. It is a kit with numerous parts and must be assembled with solder and soldering iron. It comes with a Russian made Geiger tube, which is larger and much more sensitive than my previous Geiger counter. It comes without any instructions so I had to download the .PDF file from MightyOhm.com and read it with Acrobat Reader app. For those who do not know how to read the resistor color code, the website has a full color photo of the assembled PC board so the resistors and caps can be seen.

My opinion is that it’s a good quality kit with all the correct parts (no substitutes) and is easy to assemble for the experienced kit builder. The instructions are simple and assume that you know the resistor color code. Other parts are described in more detail. One thing I really like about this kit is that it runs on two AAA cells, which are much cheaper than the other kit, which uses a 9 volt battery.

I was surprised that this kit has an ATTiny microcontroller, because it does not have a display or any way on the board to indicate what’s going on, other than the LED and piezo speaker.
Apparently this chip is for interfacing the board to a PC or other device that can display and save the counts per minute, etc. The standalone board doesn’t need it.

After assembly I inserted the two AAA cells and turned it on and adjusted the high voltage as instructed. The chirps from the speaker were clear and the LED flashed with each chirp. This kit is much more sensitive than the other kit, one reason being the much larger Geiger tube. I put the old Canon camera lens next to the tube and the counts went up to several per second, much higher than the other kit and much too fast to count visually or audibly. The radiation from the thorium glass in the lens drives the Geiger counter crazy!

The instructions also have a section on installing the completed board into a case. I haven’t seen the case.

Update Feb 15 – I got a mantle for a Coleman lantern still in its package and an orange saucer. This saucer was glazed with a glaze that uses uranium to color it orange. When I put the counter next to the saucer or mantle the clicks get so intense that they are nearly continuous. These make a great demonstration of radioactivity.

Update Feb 20 – I experimented with the orange saucer, the Geiger counter and a piece of aluminum foil. I placed the Geiger tube about a centimeter away from the edge of the sauce and I got the rapid clicks. I then placed a single thickness of the foil between the tube and saucer. I could not discern any difference in the count rate, but my ears and eyes have poor accuracy when doing this estimate. The count rate goes down a lot when the tube is moved away a foot (.3 m) from the saucer, illustrating the inverse square rule.

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2015-01-24 Free Energy Device

An interesting ‘free energy’ generator (link below).  It’s a very large light bulb to be operating from a 1.5 volt battery, especially that bright.  If it was incandescent, it would not be so bright white, which leads me to believe that it has 1 or more LEDs.  If so, then it must have a Joule Thief or similar to boost the voltage.

The light seems very bright.  But that could be deceptive.  The input current could be low, just a few tens of milliamps, same as a Joule Thief.

So then comes the device itself.  Is it really generating energy?  Or is that large capacitor a supercap that is storing the energy?  He connects the battery for ten or more seconds, which could charge the supercap.  Or the supercap could have been charged before he started the video.  Whatever the case, this could explain how his ‘free energy generator’ actually works and really isn’t free. There are other similar videos from this author using the same light bulbs.

Free Energy Light Bulb. “Free Energy”!: http://youtu.be/1XEeunKYI_c

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2015-01-20 Problems With My Phone Providers

Well, I am trying to transfer my at&t “wireline” home phone number to a new cell phone.  I’m having a very difficult time doing it.  Here’s the ridiculously long story.

My at&t home phone has the basic phone number on it that I’ve had for a very long time, so I want to keep that number no matter what happens. But I also have a third party DSL provider on the same wireline. I do not want that to be disconnected. I just want to move the phone number from at&t to Cricket Wireless. I looked at Cricket plans online and I can save ten dollars a month and get several features such as caller ID and free long distance calls that I don’t have now on my wireline. I also found that Cricket has a sales kiosk with real people in a local mall.

I went to the mall and told the salesdroid what I wanted to do, and he went ahead and started to process my purchase. When he went to ‘port’ (transfer) my phone number from at&t to Cricket, it gave two error messages. It refused to complete his request. He tried other things but came up with the same error. So he recommended I go to the at&t store, which was only a few hundred feet away in the same mall. So I went down and a nice and very helpful young lady helped me with some possible problems that Cricket may have caused. She also told me that Cricket is owned by at&t. She then sent me back to Cricket. Cricket did a few things but got the same error messages, and asked me to try the at&t store again. I went back and forth twice more but Cricket still couldn’t get the phone transferred.

Back at Cricket, the guy tried to do something else that the lady at at&t recommended, but it didn’t work. This was to call an 800 number that was supposedly only for customer reps to do ‘porting’. Another one of Cricket’s salesdroids suggested that I get my wireline number changed to a wireless number before I transferred it to Cricket.

I got a call from my friend. He said the news vans from all of the TV stations were out along his street. The big news was that someone found a KKK flyer with a Tootsie Roll in front of their house (this is Martin Luther King day). The rest of the world has so many big problems, but what makes the news is a minor incident of finding a piece of paper with just some words on it. How stupid!

I went back to at&t to tell the lady the call didn’t work. At first she tried to sell me their own wireless plan, but I told her no, their plans were more expensive and had lower data caps than Cricket. She made the same suggestion, to transfer my wireline number to an at&t wireless plan before I go back to Cricket. I asked her how much, and she said it was ten dollars. So I took her advice and went ahead with the change. She sold me a full size SIM card, did the changeover and gave me an account number and PIN.

I went back to Cricket (I’m glad they are only a few hundred feet from each other!) and gave the salesdroid the info, PIN and SIM card. With this he was able to complete the ‘port’ or changeover from at&t to Cricket.

He then put the SIM card into a flip phone and tried to call it, but it still had not been ported. He checked the computer and it said that it was still in progress. He told me that sometimes it takes just a few minutes, sometimes it takes an hour or so, and sometimes it takes a few days. He recommended that I come back tomorrow and gave me the link to the at&t online site for checking the status. I thanked him and left. A few hours later I checked and it said the porting was still in progress. I checked again the next morning, and it said it still was in progress. The message was:

Transfer Status: Your transfer request has been submitted to your previous service provider. A response has not been received. Please contact Customer Care at 1-888-898-7685.

Note: Please check att.com/port for updates on your transfer request.

My guess is that the third party DSL line is why it has not been completed. Also I think it will not be completed because the third party provider will need a phone number and the port will remove that. But I can call my number and my wireline phone still rings. Hopefully I haven’t lost my DSL service.

I have been thinking about another possible way to get data service to my home PCs. I have a Samsung Galaxy S4 with a data plan that is limited. I have turned on the WiFi hotspot capability of the phone and this allows me to log onto this hotspot with my PC. It works OK but I was surprised at how fast the data gets used up when I use Google Maps or watch YouTube videos. I can switch this phone over to Cricket and get 3 GB of LTE data for five bucks more a month (after that it slows down to 3G speed). If that’s not enough I can buy increments of 1GB more 4G LTE data for $10 a month. I can get $10 a month discount for having 2 numbers on the same account. And there is the special $100 discount until the end of the month, which I am using to pay for the LG L70 phone.

I checked the at&t site and it said that the transfer will happen tomorrow night at 9 PM. So that means the soonest I can get back to cricket is the day after tomorow.
Update Sat Jan 24 – I found that my wireline phone had no dial tone. I also lost my DSL service (I’ll have to work on that later). I went back to Cricket in the afternoon and completed the switchover or ‘port’. I found out the $100 discount did not apply to at&t, so the LG phone was no longer free. The salesdroid said that I could get the $75 rebate if I got the Motorola G, but I would have to sign up for the $60 a month plan the first month and then switch to the $35 plan the second month.

I got the phone switched over, and wrapped up the transaction (or I thought I was done). I immediately went to another store in the same mall and bought a protective case for $27. I went over to my friend’s house and while I was showing him the new phone I noticed that it would get stuck on the first screen of boot up. I took the case off the phone and the phone didn’t get stuck, it booted properly. I put the case back on and it got stuck on boot up. My friend and I determined that the case was pressing on the on/off button, and its spring was too weak, so the button stayed depressed. We went to the mall to eat, then I went back to Cricket to get it fixed.

The salesdroid agreed that the button was held down, but he thought the cause was the protective case. My friend and I went back to the store where we got the case and the salesdroid tried three other new cases to see if any of them would work okay with the phone but they all had the same problem. She said that the phone is probably the problem, so we went back to Cricket. We told the salesdroid what happened so he got another new phone and put the case on it, and it worked okay. Apparently the button was a fraction of a millimeter higher than normal, and it was a hair trigger – it clicked when pressed very lightly. I waited another half hour for him to exchange the phones and complete the switch over.

Later at home I plugged the phone into the wall adapter to give it a charge. I tried using it, but the touch screen was flakey, I would have to touch the keyboard two or three times to get it to respond. Later I tried typing but i t was even worse. I unplugged the charger and the problem disappeared! I tried a different charger but it still became unresponsive. Something is causing interference with the touch screen. This phone is a bummer!

I came to one conclusion that this was much less than a positive experience. A year and a half ago I switched my T-mobile flip phone (monthly bill) to my new Samsung Galaxy S4 (prepaid) and had a less than positive experience, but this time it was much worse.

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2015-01-18 Portable Cell Phone Chargers

My friend has been living with an old flip-phone with a crack in the still readable screen and just basic phone service, so I thought it would be good to get him a used phone, but something a few generations newer.  I got a used Samsung Zeal, which is (I call it) a flip-flop phone.  It has a flip-up lid, which displays a phone number pad.  But if the lid is flopped sideways, the keyboard is displayed.  It’s pretty cool.

But the charger that came with it has a special Samsung plug that only fits the connector on the phone.  I can’t use the standard micro USB charger cord. The other end is a 120 VAC to 5 VDC converter, not a USB connector.

I ordered some ‘lipstick’ phone chargers.  They are a round case with a lithium rechargeable cell and the circuitry inside and a USB connector to output the 5 VDC to the cell phone.  The problem is the phone’s cable needs to plug into 120 VAC, not 5 VDC.  I can’t replace the cord because it has the special Samsung connector.

So what I need is to go from 5 VDC to 120 VAC. I think if I used a 120 VAC to 6.3 VAC center tapped filament transformer with a power transistor, it might be able to put out 120 VAC at 10 watts. The frequency is probably not critical as long as it’s somewhere in the audio range.

I was thinking of another solution. I could tap into the plus and minus wires of the special cable. I could then solder a 1N5817 Schottky diode and a cable with a USB connector on the end so it can be plugged into the ‘lipstick’ or any other charger. I may not have to have the diode at all, depending on the output circuit of the charger.

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2014-12-31 Almost New Years – Phone Problem

December 30, and about 25 hours before a new year.  I should change all my smoke alarm batteries.

Since I’ve had my Samsung Galaxy S4 phone, I have had trouble with the phone touchpad during making or receiving phone calls. Soon after I got it a year and a half ago I got a Body Glove case and screen protector for it. Also it got the upgrade from Jelly Bean to KitKat. I started to have problems with the phone and I initially thought it had something to do with KitKat. The screen would go black during the call, and almost nothing I did would make the touch dial come back. Sometimes I could press the on/off button and get out of the phone and back to the apps.

Recently I found that the screen protector was getting scratched so I got a replacement Body Glove, with a dark blue case with light blue trim. It was much better with no scratches. Still the phone calls were just as bad if not worse than they were before. If I tried to erase my voice mail messages, it was nearly impossible, as were any interactive menus during any call. It got to the point where I gave up on my VMs, and that wasn’t all that bad because most of them were robocalls and spammers.

In mid- December, I got a message that my S4 was due to be updated to Lollipop. I was hopeful that whatever was causing the phone problem would be fixed in this update. But I was sadly disappointed to find that the update didn’t help – no change.

As part of turning over a new leaf this new year, I decided to do some searching to see if I could find some info and possibly narrow the problem down to some menu setting or whatever to make the problem go away. I did find several hits, one of which was about a proximity sensor. So I found some details online about this, including where it was located. The sensor is located to the right of the earphone, at the top, next to the edge of the Body Glove case. There are holes in the screen protector to allow the two devices to be unobstructed. Well, everything looked okay to me; the sensors were not obstructed. But to make sure I took the Body Glove case off and cleaned the screen to the right of the earphone. I then made a call, and it worked! No more problem! So I put the Body Glove case back on and tried to call, and now the problem is back!

This really had me flummoxed. What is causing the case to create the problem? Was it the light blue trim that is just above the sensors? Is it the screen protector? I can’t see how because the screen protector has a hole that does not block the proximity sensor. What is it? At least I know what is causing the problem, but what can I do to fix it other than to get rid of the case? I will have to experiment to find out.

Update – I decided that it might help if I took a black magic marker and covered the light blue trim above the proximity sensors with dark black. I drew over the light blue trim, but moving the tip seemed to cause the black ink to thin out. So I made a series of dark dots and it looked a lot darker. The black is about 0.4 inch or 1 cm wide. I tried making a call and it worked! Such an easy fix. And all these months I have been using a phone with a screen that was unable to show the display during a phone call, just because the Body Glove case was reflecting the light back into the proximity sensor, making it think it was always against my ear. If only I had done this a long time ago!

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2014-12-30 The Day Before New Year

December 30, and about 25 hours before a new year.  I should change all my smoke alarm batteries.

I was watching This Old House recently and the electrician installed new outlets in a very old house that had a gas chandelier that had been converted to electric lights. He showed how the new work had to meet current electric code by having AFCI breakers or outlets. This is an Arc Fault Circuit Interrupter. If there is a high resistance that is causing an arc (and therefore a lot of heat and possibly a fire), and would not trip a normal circuit breaker, then this AFCI breaker would detect it and trip, shutting off the circuit. Outlets with AFCI are also available but a built-in light socket would still need an AFCI breaker. Also several AFCI outlets on a branch circuit may be more expensive than a breaker.

They said that AFCI can interfere with power line data communications, so it may be necessary to add datacomm wiring. I personally don’t like datacomm over powerline because it can cause interference with radio and TV and may not be private and/or secure.

After this show I started thinking of my house and its antiquated Pushmatic circuit breakers. I’ve been told that they sometimes don’t work and have caused electrical fires. It would be a good idea to replace them with a new breaker panel with AFCI breakers. However, this could cost thousands of dollars U.S. and there could be other costly problems that may need to be addressmonthUpdate – I saw several trucks with the name Solcius on the side parked at two of my neighbor’s houses, and guys working on their roofs. They are apparently getting solar panels installed. But these are the kind where the company owns and maintains them and gives the house owner a discount on his electric bill. I have a friend who bought them and the solar panels are his own, and he gets all the benefits and has to maintain them. I personally think this is better than the lease/discount way. In my case my electric bill is so low they won’t consider me for the plan. Your bill has to be at least $150.00 a month to be considered.

Still on the subject of electricity, I watched a program on PBS about a city in India where the electricity service is stolen from KESCO, the local electric supplier. They used a name, starting with K, for the electric piracy. They interviewed one of the pirates, a young guy who had been injured numerous times, and also been hospitalized. The power line voltage is 240 volts AC there, and that can cause serious injury, and he’s lucky he hasn’t been killed. They had a priest bless the transformer that feeds the section of the town. They showed people trying to put out a fire from hot oil leaking from an overheating transformer, and transformers arcing and sparking and wires burning. The power poles look like a rats nest of wires. They said that as much as 30 percent of the electricity is stolen by pirates. It was an interesting program to watch.

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2014-12-18 A 1 Watt LED Gets Thermal Adhesive

I got some 1 watt LEDs from Goldmine Electronics for 5 for $10 (They were on sale when I bought them).  These are LEDs that do not have a mounting bracket, but were made for surface mounting. I’m not sure if the case itself is supposed to be held to the PC board only by the two solder tabs, or if the case was also meant to be glued to the PC board.  I decided that no matter, I was going to glue the case to the board with thermal adhesive.

So I searched online for thermal adhesive and found that the local Microcenter has two-part thermal adhesive made by Arctic Silver.  I’ll use any excuse to stop by a computer store, so I went and and bought the adhesive for ten dollars US.  It’s apparently epoxy with a large amount of thermally conductive alumina ceramic powder.

I needed something that is highly thermally conductive to use as the heat sink for the LED.  I chose a short piece of 6 AWG very heavy solid copper ground wire I bought at the big box hardware store.  I could have used a piece of thick aluminum or a piece of scrap PC board.

IMG_20141219_190104S3This 6 AWG wire is heavy and round. How am I going to get the LED to fit? I decide to hammer it flat, with a right angle “foot” at the end for the LED. I used a ball peen hammer and a heavy piece of steel. It came out nicely. First I turned on a stove burner and held the end of the copper ground wire in the flame for a few minutes to anneal the copper to make it softer and easier to work. After flattening the end, I bent over the flat part so it all looked liked a leg with a foot. I filed the sole of the foot flat with a file so the LED would make good contact with the copper.

Mounted the foot with the sole up in a vise. I mixed even parts of the adhesive and put a small blob on the sole, and I seated the LED in the adhesive. A half hour later the adhesive was hard and the LED glued ‘permanently’ to the copper heat sink.

I added short lengths of copper wire to the LED’s mounting tabs and put them and the heavy copper wire inside of heat shrink tubing so the wires would pull on the heat shrink, not the tabs.  in the photo, the cathode’s minus sign can be seen on its side, looking like a 1.

I connected the LED up to a power supply and turned up the constant current to 200 mA. To my surprise, the LED put out warm white light, just like an incandescent light bulb. Very nice! It took a long time for the heavy copper heat sink to get warm, but the 1 watt LED rated at 350 mA max was running at only 200 mA. It still had more than 100 mA to go.

In the past I have mounted 4 or more standard 5 mm white LEDs on a perf board and fastened them to various locations for task lighting. They do a good job, but it requires assembling the circuit board before it can be used, and other design decisions. With these 1 W white LEDs, it just requires a small metallic surface to act as a heat sink and some thermal adhesive for a few tens of minutes. Then some wiring and a 5VDC, 1/2 amp AC adapter and a resistor. The resistor calculates to 8 ohms at 1/2 watt. But some of this resistance might be in the thin wiring to the LED. Put these all together and it’s a very handy task light.

I have other surface mount LEDs that come in a case that is epoxy and are so delicate that it’s often damaged by hand soldering. With this thermal adhesive it may be possible to position the LED and wires, then glue everything in place before soldering. I will have to experiment with this later to find out. I can also glue LEDs to a length of angle aluminum and mount the strip under a cupboard, for example.  The thermal adhesive makes it possible to get away from Star LEDs with the screw slots, and drilling holes in a flat piece of metal.

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2014-12-12 I Setup A New Samsung TV

My ‘old’ TV was a Samsung 40 inch I got 1 year ago.  I should have remembered how many problems I had last year when I set it up.  This new Samsung 46 inch is just as bad, if not worse.

I do not want to setup the TV by having it search for all the available channels.  There are many more than a hundred in So. California – one single foreign language station by itself has 12 programs, each one has to be deleted. 
If I let it search for all the available channels, then I have to go back and manually delete hundreds of them except the dozen that I want to keep.  So I tried to add the channels and it’s as difficult as manually deleting all the ones I don’t want.  What a headache!

I opened up the pamphlet that came with the TV but there was nothing in there about how to add a channel. It turned out that it was in the e-manual stored in the TV’s memory. Every time I wanted to go back to read the e-manual I had to quit whatever I was doing and then go back through the menus to get back to where I was.

So I started from scratch. I tried to add a channel. It insisted I had cable, even after I had selected air earlier. I finally got past that stumbling block.

I tried to add a channel but the stubborn TV decided that it wouldn’t let me; I could only let it add all available channels. After several tries, I gave up in disgust and started the add all channels, but a few seconds later, I turned off the power. When I turned it back on, only three channels were added. Oddly, two of these didn’t seem to have any stations.

I fought with the process of going to the e-manual then back through the menus to get back to where I was. I managed to add a few channels. One major problem is that when the U.S. switched over to digital TV, all of the low VHF channels from 2 to 6 were moved up to the UHF band. So if you add channel 2, there’s nothing there. You have to know where the actual channel is. It might actually be channel 41 or whatever. I’m still working on this.

The user interface was very poorly thought out and felt clunky. All of this added up to a very frustrating experience. It was horrible. I’m just thankful that I don’t have to go through this more than once!

Now that I have used it for several hours I find it sluggish and less responsive than last year’s TV. I’m guessing that the processor has to handle all the other new stuff that has been added such as WiFi, Smart TV, and all the pay stuff like Netflix, etc., etc. It seems as if it’s a product that was rushed to get to the stores, with rough edges that annoy the user but aren’t critical to its operation. The only thing better than the 40″ is I don’t have to hear the four note startup chime waste time when I turn it on!

More Complaints
It’s the 15th, Xmas 10 days away. I’d like to make a few things clear. I have not yet connected the TV up to the network yet, so it has not had an opportunity to download any updates. But I didn’t have the old TV connected to the network, and it worked okay, with none of the complaints that this one has.

That said, I found another annoying thing. On the two older Samsung TVs I had, pressing the info button gave the current program, and also gave the next, upcoming program. This TV does not give the upcoming program. What?! Why not? Cheap junk software!

As I add, delete or change the channels, I found that all I have to do is punch in the channel number, like 28-4, and it adds the channel. But when I want to delete that channel, I have to go through several menus just to get to the point where it will let me check the box, then go to the delete button. What a turkey. I’ve seriously considered putting it back in the box and taking it back. Yes, I think it is that bad!

A friend advised me to plug it into the internet and let it update its software. Yeah, I think that’s a good idea but I think that it’s so bad to begin with that even if it’s updated, the new updated software would suffer from the same problems.

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2014-12-11 More Geiger Counter Sources

After my first feeble attempts to find a source of radioactivity to test my Geiger Counter, I took one of Paul’s ideas and tested several old 35mm camera lenses.  I tried a very old Asahi SLR (before Pentax) but I got no radiation.  Then I tested 2 Canon EOS cheap lightweight plastic lenses, still nothing.  I tested a Vivitar lens, but no radiation.  I tested the telephoto lens of a Canon FT, still no clicks.  I tested the wide angle lens, zero.  I took the 50mm lens off the Canon camera, and when I held the back of the lens to the Geiger tube, the clicks went from 1 or 2 a minute to 1 to several a second.  SUCCESS!!

Some camera lenses used thoriated glass.  This was one of them. It says CANON LENS FL  50mm 1:1.8 on the front.  This is not a lightweight plastic body, it’s the real thing.  It’s heavy, so I think it’s made of brass.  And the rear lens drives the counter crazy!

Next I tested the inside of a smoke detector.  The openings around the metal can are like the blades of a squirrel cage fan: the fin is bent inward and lets the smoky air through, but each fin blocks the radiation source in the center so it can’t be seen, and the radiation can’t get out.  My test of it gave no increase in the click rate.  The smoke detector is unusable, so I may take the cover off the radiation source, but first I’m going to read up on it to find out how to avoid any unsafe conditions.

What I read said this is NOT a good idea. It is unsafe. The radioactive source can’t do harm if it stays in the detector. But if it gets damaged and particles come loose and enter the body through the air or digestive system, they can cause cancer. So for now, I think I’ll leave the detector alone.

I still have to take the Geiger counter down to the creek bed and test some of the rocks there, but a storm is supposed to hit hard here this afternoon, and it looks like I may not be able to walk in the creek bed for quite awhile until it dries up.  No telling when that may be, since other rain may come soon after.  After three years of drought, we really need all the precipitation we can get, especially snow in the mountains.  And it’s saving me $$$ on my water bill because I don’t have to water the lawns.

Update Dec 12 – I cut off the end of a banana and held it close to the Geiger tube. It seemed like the count was higher, but that was just what I perceived, so I decided I would have to time the readings. I timed the background radiation and got 5 clicks in 2 minutes. Then I timed the banana and got 16 clicks over a 2 minute period. Definitely higher than the background radiation.

Yummy banana got eaten – my resistance yielded to temptation. So now I have (and always have had) radioactive potassium inside me, I decided to measure the count with my finger next to the Geiger tube. In one 2 minute session I got 7 counts, and in a second I got 10 counts. My finger seems to be higher than the background radiation, but the count really needs to be averaged over a much longer time to average out the randomness. But I don’t think I have the patience to hold my finger there for a half hour or more. So this confirms that bananas, or for that matter, any other living thing that has potassium, has a radiation count higher than the background count.

I have several rocks laying around that I should check for radiation. One problem I’ve found is that if the level is low, it may take a long time to find that it’s different than the background count.

I have a piece of galena on a shelf, so I tried that in front and on top of the Geiger tube for a few minutes. I heard nothing for quite a while. That makes sense since galena is mostly lead, and is so dense that it shields the tube from radiation. My guess is that a lot of the background radiation comes from above in the form of cosmic rays from space. A lot of these are blocked from above by the lead, so the background radiation count drops.

The galena crystal is about 13mm thick. That’s about 1/3 the thickness of the outer and inner stucco walls of my house. Apparently the lead is much more effective at blocking radiation than the walls or ceiling.

The banana was definitely higher than the background count. I have some potassium citrate capsules. They were dirt cheap, $2.50 for 120 capsules, from Swanson vitamins – about 2 cents apiece.

I put two of the capsules next to the Geiger tube, so far it doesn’t seem to be higher than the background count. It’s definitely less than the banana. For this reason, I think the banana is better, especially since the remainders serve an additional purpose (yum!).

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2014-12-09 Power Bank Recharges USB Devices

I have been working on my own “Power Bank” for recharging my cell phone.  I went to the NOCCC Computer Club meeting last Sunday and to the Mobile Computing meeting.  Ben, who started this meeting, decided that he wanted to buy some ‘power bank’ USB chargers for himself, family and friends.  He could’ve got then from Amazon but they don’t take PayPal, which he insisted on using.  So he bought them from Alibaba.  The one catch was the minimum amount he could buy was 10.  At that price they were $18.42 US. apiece.  After he was done with what he needed, he had 5 left over, which he offered to us for $20.00 apiece.  So I couldn’t resist buying one.

It is from China of course and the instructions are a very rough translation of Chinese into English.  The battery capacity is 8000 mAh or about 1 amp for about 8 hours.  It says power bank on it, but gives no company name. It’s about the same width and thickness as my Samsung Galaxy S4, but it’s more than an inch taller. I charged it up before I left, but I didn’t use it on my phone; instead we charged her almost dead iPhone. While she was talking on it for about an hour. By the time we got back home the iPhone was at 50% charge, even though Bucket Mouth was blabbing away most of the time! (I’m probably going to get in trouble for saying that!)

So it works okay. It has a 5mm white LED next to the on/off switch, but I haven’t seen it light up yet. I didn’t read anything about it in the instructions. But I was looking on eBay and Amazon to find one like it (because I refuse to buy anything more from Alibaba) and many of the others have a built-in flashlight. So this LED may be a flashlight but I don’t have the power bank to find out. Bucket Mouth thought it was so great that she ‘borrowed’ it, and from past experiences, I know that I may not be getting it back! Oh, well, I guess I can call it a Xmas present. 😉

My guess is that I could press and hold down the power button for a few seconds and the LED would turn on like a flashlight. I’ll have the call Bucket Mouth and ask her to try it. Later, if her phone isn’t busy…

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