EMF SNIFFING HAT

EMF SNIFFING HAT
KENNETH LEUNG, 2254027
OVERVIEW
Summary
The EMF Sniffing Hat project seeks to create greater awareness, for users, of
the pervasiveness of EMF (electromagnetic frequency) radiation in their environments. The hat is whimsical in form and behavior -- it resembles a large-eyed
creature with a long proboscis (containing the EMF sensor), and sings a series of
musical beeps, whose tone corresponds to the intensity of EMF in the surrounding area. By employing a humorous aesthetic and interaction, it is intended that
the user’s relationship with the hat be one of curious exploration and engagement, rather than fear and anxiety (which the topic of EMF normally evokes).
How It Works
The hat is equipped with a Lilypad Arduino microcontroller, and a EMF sensor
(a long electrode attached to the microcontroller). The microcontroller reads the
value from the sensor and plays a different musical note (frequency) based on
the level of the value. The notes are played through a earbuds, which are embedded in earpieces on the hat.Pressing a momentary switch will enable playing of
the notes through an external speaker as well.
Components
Electronics:*
- Arduino Lilypad
- Solid core wire (used for emf sensing antenna, and internal circuitry)
- AAA battery holder
- PC Speaker (external speaker)
- Earbuds (internal speaker)
- Momentary Switch (to turn external speaker on and off)
- Solder (for attaching internal wiring)
- 3.3M Resistor (used to regulate current, to keep
sensor data within a usable level)
* I made a personal challenge to myself, for this project, to use only
components I’ve scavenged from broken devices I have lying around,
instead of purchasing them. This was a success -- most of the electronics
parts (switch, resistor, speaker) come from an old answering machine.
Materials:
- Red terrycloth fabric (skin of the hat)
- Foam insulation tubes (structure for the proboscis)
- Ear muffs (for embedding of earbuds)
- Velcro (used to attach materials, so that they can be
removed to access electronics)
- Winter cap (structure for the hat)
PROCESS
1. EMF Sensing
To mock up the most basic functionality, I created a basic EMF sensor using a
loop of wire (sensor), attached to to analog pin 2, and an LED attached to digital pin 8. The LED would light up if values from the sensor exceeded a baseline
value.I experimented with different lengths of antenna, and made sure that sensor values would still be usable when the antenna (wire) was about 3 feet long
(the intended length of the sensing ‘proboscis’).
2. Haptic Output
To gauge the effectiveness of using haptic (vibration) output in the final
prototype, I attached 5 vibration motors in parallel and hooked them up
to two AA batteries. I then put these components into a pouch (to simulate
embedding within the hat). Both basic vibration motors (motor with off-balance
shaft)and disc-based vibration motors, were experimented with. Resistors were
placed on the circuit to gauge effects of different current levels. It was decided
that there wasn’t enough variation in the sensation to create a compelling experience.
PROCESS
3. Audio Output
To test the meaningfulness of audio output, I added a PC speaker to
digital pin 8 on the emf sensor setup from iteration 1. I then added code
to play different tones (beeps) depending on EMF sensor values that were
multiplied by a factor. I adjusted the speed (delay), and multiplication factor
several times to figure out what would make for the most whimsical experience,
and to establish a baseline.
I also tested the setup with white noise generating code, to see how the
experience would be with something that sounded like radio static (and seemingly a good ‘visualization’ of EMF). The resulting experience seemed a bit boring,
and it was also difficult to gauge differences in different levels of white noise.
All this circuitry was mounted on a yarn winter cap, which was used as the internal ‘structure’ of the EMF hat.
4. Audio - Public & Private Experience
I wanted to create both a public and private experience -- i.e. so that both the
wearer *or* other people could hear the emf sounds, at the discretion of the
wearer.To facilitate this, I added two earbuds in parallel to the speaker circuit (pin
8). I also added a momentary switch behind the PC speaker, so that the wearer
could choose to broadcast the emf sounds to other people, with the default being
a private experience played only through the earbuds.
Challenges
Calibration issues:
Experimentation was required to:
- Establishing proper baseline for EMF readings
- Accounting for EMF from FTDI USB adapter, which was attached during testing
- Optimizing of length of sensor wire (to get the most meaningful level of
readings)
Structural
- Keep ‘proboscis’ from sagging under weight - solved by attaching a strap to the
tube, whose other end was attached to the back of the hat to provide a
tensile support.
Interesting Findings
. Human body gives off a considerable amount of EMF (people’s bodies
emit EM fields); Also, different people give off different levels of EMF
. Laptops, televisions, computers emanate the highest level of EMF
. Certain sections of wall cause emf sensor to spike - could be caused
by concentration of power cables
. Grounding of objects (e.g. touching a laptop with hand)
reduces level of emf greatly
Next Steps
. Improve structural strength of the hat
. Multidirectional sensors
. Use conductive thread instead of wire for circuitry
to improve better flexibility
. More fine-grained sound output
RELATED WORK
Related Projects
EMF Bracelet
Cati Vaucelle, MIT (2009)
Antenna (fashioned from copper fabric) picks up EMF, which is amplified by opamps.A feedback LED lights up according to EMF level. The project doesn’t make
judgment on whether EMF is good or bad, but seeks to relieve anxiety by eliminating fear of the ‘unknown‘ (the invisible).
Arduino EMF Detector
Aaron Alai
Simple proof-of-concept project which detects, reads, and visualizes EMF (via an
LED) using an Arduino Diecimila.
IMAGES
EMF Sniffing Hat:
Final Prototype
‘BUTTON’ TURNS ON
EXTERNAL SPEAKER
(Looks like a group
of small green
dimples)
Interactive parts
on the EMF Hat
surface
ACCESS FLAP
(allow access
to on/ off switch)
Bottom of hat, showing
earpieces (with embedded
earbuds)
Initial Prototype:
Structural Components
IMAGES
Initial Prototype
(sans electronics)
ACCESS FLAP
(allow access
to on/ off switch)
Internal wiring of the
EMF Sniffing Hat
Initial prototype
with electronics
attached
ACCESS FLAP
(allow access
to on/ off switch)