Hand Hygiene

Magnet Info:

• Size and shape play a large role in determining the strength of a magnet.
• The grade of a magnet directly refers to its Maximum Energy Product [MGOe].  Generally, a higher grade represents a stronger magnet (i.e. for a neodymium magnet, grade 40 = N40 = 40 MGOe)
• Alnico magnets are manufactured by either sintering or casting.  Sintering = higher mechanical strength, Casting = higher energy product
• Pull force tests are not standardized

• General strength according to material:
  

  Material	Strength	Pros	Cons
  Ceramic	Low to Medium (grades 1 – 8 )	Low cost High coercive force High resistance to     corrosion	Low energy product Low mechanical strength (brittle)
  Alnico	Medium	High resistance to corrosion High mechanical strength High temperature stability	High cost Low coercive force Low energy product
  Rare Earth (neodymium-iron-boron, samarium-cobalt)	High to Highest (grades up to 52)	Very high energy product High coercive force	High cost Low mechanical strength (brittle)
  Flexible	Very low	Low cost High resistance to corrosion Moderate coercive force	Low energy product Low to medium temperature stability

  References and suppliers:

  • www.mcmaster.com
  • www.supermagnetman.com
  • www.rare-earth-magnets.com
  • www.allmagnetics.com
  • www.kjmagnetics.com

The same test was run with the Purell (9 configurations, 3 angles, 3 locations) to see if the handwash credit goes to the right person at .5 and 1.5 meters and .5 and 2.5 meters.

Here are the results:

Data for .5 and 1.5 meters with the right hip was not available because the data couldn’t be downloaded. We still see a huge variation. Maybe we can improve our testing method?

Geb and I tested the Purell data to if handwashing credit goes to the right person. We stood with three pagers on our left/right hips and chest and recorded data from .5 and 1 meters away (the value stated on the graphs is wrong). We conducted this test with 9 different configurations, at three angles.

From the data, we see that the best location for the pager is the right hip. We also see that the worst location for the pager is the chest. There is a lot of variability in the data. maybe increasing the distance will help.

I have written a new trigger program which records the time of each pump to flash. The time it records is local mote time, so remember to note the time the trigger was turned on. The program makes the blue LED turn on whenever the pump is pushed down. If the mote fails to write to flash, the red LED will flash.

It is on the Ubuntu computer upstairs in ~/Desktop/newtrigger . It contains subdirectories for reading and clearing the flash. Refer to the readme in ReadFlash for information on how to read the flash.

The three modified triggers are currently programmed with this program.