Sources of Noise: SID Monitor

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Sources of Noise SID Monitor

• By Szu-chiech Lu and Mathieu Evans

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• Project Objectives
• In addition to investigating potential sources of
  noise from everyday electronic devices in school
  or office settings, our hope was to create a
  catalog of sorts that would visually portray
  different types of noise both quantitatively and
  qualitatively.
• Why?
• Our own SID monitor back home was experiencing
  frequent signal disturbance during the daytime
  that was unexplainable. When we came to Stanford
  and began to brainstorm potential project
  directions, the noise problem we had on our hands
  back home was at the forefront of our mind. So,
  there was some element of personal satisfaction
  in problem-solving in our motivation.

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Experiment Sources of Noise

• Successful
• Fluorescent Light Bulbs
• Vacuum Cleaner
• Microwave Oven
• CRT Monitor
• Gas Lamp

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CRT Monitor

• The reason the old computer monitor we used
  generated noise was because cathode tubes were
  present in the monitor.
• Loud noise generator via the power speakers
  utilized by the SID monitor.
• Noise/Interference ceases when the computer
  monitor is approximately 4-5 meters away from the
  antenna.

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CRT Monitor

• Old CRT Monitor
• 1m away
• Values were high, but not quite to the rail
• Placed perpendicular to the antenna

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CRT Monitor 2

• Moved the monitor to 2m away
• Reduced effect
• Appears to have ¼ noise strength
• Seems to follow the inverse square law

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Gas Lamps

• Very strong noise generator and the most noise is
  present when the tubes themselves face the
  antenna in a perpendicular fashion.
• Placing the gas lamps in this fashion, the noise
  ceases at approximately 3 meters from the
  antenna.
• Placing the gas lamps in line with the antenna,
  the noise ceases at only 2 meters from the
  antenna.
• The graph showed an unexplainable oscillation of
  noise levels. In other words, the voltage reading
  would drop back down into the value range wed
  previously calibrated for no apparent reason and
  without turning off the gas lamp. It would also
  rise back up near the value rail only slightly
  lower than its first sudden increase. In one
  test, the high value was maintained. It is
  unknown whether or not this process of
  oscillation would occur again, much less
  perpetually.

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Gas Lamp Noise

• Turned on the gas lamp at 1m away
• Sharp rise followed by a dip
• Then rose again and maintained

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Gas Lamp Noise 2

• Gas Lamp at 2m away from antenna
• Appears to have no effect at 2m
• Optimum Distance

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Vacuum Cleaner

• The reason we felt a vacuum cleaners was an
  important device to test was because school and
  office settings have janitors that might be less
  than considerate as to where and when they
  vacuum.
• The vacuums noise performed much like the CRT
  monitor in the sense that the further it got from
  the antenna, the weaker the noise. Noise appeared
  to disappear after about 13m for certain so it
  was significantly stronger than the CRT monitor
  and twice as likely to pose a threat.

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Vacuum Cleaner Noise

• Besides the microwave, vacuum cleaners are also
  very noisy
• Also made the SID monitor data hit the rail

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Vacuum Cleaner 2

• More realistic vacuum cleaner graph
• We simulated vacuuming by eractually vacuuming
  the hall

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Microwaves (a.k.a. pure evil)

• When I say evil, I mean that microwaves are quite
  possibly the most powerful and consistent source
  of noise that can be thrown at the SID monitor.
  It seemed to have a
• We tested the SID with microwaves about four
  times by ourselves before we looked at our data
  via Logger Pro 3. The times when it was being
  used by others in the building throughout the day
  showed up on our graph as well.
• As soon as the microwave was turned on, the
  voltage value hit the rail almost instantaneously
  and remained there for the duration of the time
  it was on.
• As soon as the microwave was turned off, there
  was a certain amount of time needed for the SID
  monitor to make a recovery (recovery time for a
  given test increased slightly after every
  successive test), but the voltage value returned
  to our previously calibrated value (-2) for every
  testexcept one!

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• Todd came down to check our projects progress
  and when we told him about how our microwave test
  reflected the possibility that microwaves have a
  noise range of more than 25m, he wanted to see it
  for himself.
• We turned on the microwave in the upstairs
  conference room and the voltage value hit the
  rail once again. After a minute, we shut the
  microwave off and after five minutes of waiting,
  the voltage values did not recede back to our
  previously calibrated values. In fact, for that
  individual monitor, the values never receded,
  even after unplugging it, restarting it, or
  practically taking it apart.
• Next, we tested a new monitor and the original
  DATAQ and this monitor worked fine and was still
  affected by the microwave. Its voltage values
  recovered properly as expected though.
• Next, we tested the new monitor while placing the
  antenna outside of the building. For one test, we
  placed the antenna sixty feet away from the
  microwave and for the second test, we placed it a
  little over 10m away. This concluded our
  microwave testing.

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Microwaves

• When used within 30ft of the antenna, a microwave
  will cause the signal to rail at 5.00 volts
• Microwaves would not have an effect on the
  antenna at 60ft away

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Microwave 2

• Microwave at about 20 meters away
• No effect on antenna

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Experiment Non-Noise-Makers

• Unsuccessful
• Electric Fan
• Refrigerator
• Human Contact
• Office Computer
• Radio/Boom box
• Horseshoe Magnets

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Electric Fan

• We thought that the fan motor would have an
  effect
• Apparently not, even at 1m

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Radio/Boom Box

• We also though that the radio frequency that
  radios receive
• As it turns out, the SID Monitors behave just
  like radiosthey only receive signals

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Future Research

• If the SID monitors malfunction is a direct
  result of repetitive exposure to microwaves, this
  reflects one of two possibilities either the
  individual monitor had a faulty part or the
  entire first generation of SID monitors has an
  inherent design flaw. If it is possible to break
  a SID monitor with a microwave from significant
  distances, students experimenting need to be
  informed so they can find a proper place in their
  school to conduct their experiments. Also, it may
  be necessary to redesign the SID so that money is
  not wasted in their production and distribution
  if they are susceptible to such common devices.
  Future research is necessary to determine the
  fate of the SID monitor whether good or bad.

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Uncompleted Project

• Yes, there is one.
• Originally, we planned to complete the noise
  catalogue and another project concerning how the
  data collected by SID monitors at different
  locations would differ. We were not able to
  complete this project was not because there was
  no time, but instead, the reason was that we did
  not have several crucial pieces of information
  about the SID sites around the world.

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Needed Information

• Local weather conditions
• Specification of the antennas at different
  locations
• Flare(s) that occur at EXACTLY the right time of
  day
• Without these important pieces of information, we
  were not able to complete this second project we
  had in mind to complete by the end of our two
  weeks (today). This may be possible in the
  future when there are much more sites sending
  information to the Stanford SID Database

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THE END