Thursday, March 24, 2011

Geiger Counter Antics - Part 1

Well, I recently bought a Geiger Counter. If you want to look at the specs, click here. It counts Alpha, Beta and Gamma radiation.

I have decided to measure, over the course of several days and weeks, the counts per minute around me. I will do a count outside (in my driveway) with the device pointing to the sky, and also indoors. Obviously the readings are somewhat random, so I'll take 5 readings and average them. Outside has a CPM of about 20 at the moment.

I also decided to take readings of various household objects, just for fun. One thing I was somewhat concerned about was the granite benchtop of our new kitchen, as I had heard of people with highly radioactive slabs. Ours does produce a higher count than ambient, about double in fact, but I am not worried about that. It's about the same as a common housebrick, with a CPM of around 40.

The only source of radiactivity in the house, that I know of, is in a smoke alarm. I had a spare one, so I took it apart just enough to expose the metal housing of the radioactive unit. That is, I removed the plastic cover only. There is a sticker that says it has a tiny piece of Americium in it. A direct reading on this metal housing gave a CPM of over 100. Moving away a few centimeters and taking a reading it dropped off considerably back to background levels. Don't panic about your smoke alarm, it's not going to kill you unless you break it open and eat the contents, and even then I'm not sure it would be a lethal dose. Still, I don't recommend it.

I wonder if the issues in Japan, which are a long way away, will show in my readings. Time will tell, and I'll get back to you on that.

ODBC connection issues in Windows 7

OK, so you have a database (eg SQL server) with an MS Access or similar front end. You have been using ODBC to connect to this database without issues for literally years with Windows XP clients. Recently you upgraded to some Windows 7 machines, and now the connection is not working -- what's gone wrong?

Well, the short answer is ---

For Windows 7, Connect using a User DSN rather than a System DSN in the "Data Sources (ODBC)" control panel.

I am not sure why the System DSN's are broken in Windows 7, but it seems they are.

Although it works in Windows 7 using a User DSN, this is not as good in some ways. If the machine is used in a hot-desk environment, then you will have to set up the ODBC driver for each User, rather than once for the System. For hand-me-down situations, it's one more thing to remember to setup. I have not tried a Terminal Services machine lately, but it's likely to be a pain in the butt on these as well.

If this post helped you, please leave a comment!

EDIT : 2012-05-31

I have had reason in my professional life to revisit this annoying issue, and have some more information to add.  It turns out that this is a 32/64 bit issue, and there are TWO versions of the ODBC admin control panel, based on 32 or 64 bit. It is explained in more detail in this knowledgebase article, which I recommend you read in full

What I love about this situation is the classic brain melter, and I quote ....

  • The 32-bit version of the Odbcad32.exe file is located in the %systemdrive%\Windows\SysWoW64 folder.
  • The 64-bit version of the Odbcad32.exe file is located in the %systemdrive%\Windows\System32 folder.
I had to read that one about 3 times before it sunk in.  The 32 bit version is in the SysWow64 folder, and the 64 bit is in the System32 folder. Hmmmm, logical.

Anyway, this all explains the behaviour and fix above - for USER DSN's, either version handle 32/64 bit, but for the MACHINE DSN's you have to use the right one, and the 32 bit is more common for older drivers and it's not the default tool in Win7 64 bit installs. I think I got that right!!