In
this week I have done some research about the hardware and I have come up with 6
ideas for my project and I draw it …
My drawing is not that good but I put
some explanations so it can be more clearly.
Wednesday, 19 September 2012
Tuesday, 18 September 2012
WEEK 5 => 3 Sep - 9Sep
Proximity Sensors
Proximity
Sensors are available in models using high-frequency oscillation to detect
ferrous and non-ferrous metal objects and in capacitive models to detect
non-metal objects. Models are
available with environment resistance, heat
resistance, resistance to
chemicals, and resistance to
water.
Proximity sensors are
switches or sensing devices that can detect a nearby, specific object without
actual contact. There are three types of proximity sensor: inductive,
capacitive and magnetic. They can be either shielded or unshielded. Typically,
all require close positioning to the object being sensed (about ½ inch or
less). Proximity sensors require almost no maintenance, and most are resistant
to environmental contaminants and conditions.
The maximum distance that this sensor
can detect is defined "nominal range". Some sensors have adjustments
of the nominal range or means to report a graduated detection distance.
Proximity sensors can have a high
reliability and long functional life because of the absence of mechanical parts
and lack of physical contact between sensor and the sensed object.
Sharp GP2D12
Distance Measurement Sensor
This sensor takes a
continuous distance reading and reports the distance as an analog voltage with
a distance range of 10cm (~4") to 80cm (~30"). The interface is
3-wire with power, ground and the output voltage.
Features
- Very Small in size
- Less influence on the colour
of reflected objects, reflectivity
- Analog voltage corresponding
to distance
- Detecting distance of 10 to
80 cm
- External control circuit
unnecessary
- Low cost
-->>Press here for Data sheet link
Infra-Red Proximity Sensor Part 1
This proximity sensor,is easy to build, easy to
calibrate and still,it provides a detection
range of 35 cm
This sensor can be used for most indoor
applications where no important ambient light is present.
The basic idea is to send infra-red light through IR-LEDs, which
is then reflected by any object in front of the sensor .
Then all you have to do is to pick-up the reflected IR light.
-->> Citation: http://www.ikalogic.com/infra-red-proximity-sensor-part-1/
Infra-Red
Proximity Sensor Part 2
This article deals with a more advanced IR proximity sensing
scheme, as compared to the one proposed in the previous
article. It is also more expensive but provides more accurate
results even in sunny outdoor environment.
The Principle of operation
As I said, the main idea behind obstacle detection using IR is to
send Infra-Red (IR) light in a certain direction, and if an object is
present no too far from the sensor, IR will be reflected back and detected by
the sensor. But as you may already know, one of the biggest problems that can
cause the malfunctioning of an IR proximity sensor, is the ambient light and
surrounding sources of IR like the sun and halogen lamps that can cause false
triggering of the sensor.
 |
| figure 1.A |
The
ingenious solution that was developed to avoid this problem, is to send pulses
of IR light at a certain frequency instead of a constant beam, and build a
receiver that would only detect IR pulses of the same exact frequency, cutting
of all pulses of higher or lower frequency.
The kind of device capable of
filtering signals this way is called a bandpass filter. There are a lot of
types of bandpass filters, a whole branch of electricity is dedicated to this
subject. Instead of building a band pass filter, we used a very common IR
receiver Module as the one shown in figure 1.A.
That incorporates a receiver, an amplifier and a very reliable filter that
rejects all the signals that are a couple of kilohertz far from the original
central frequency, all in one single integrated circuit, just as big as a 5V
regulator. The central frequency is fixed by the constructor usually at 40 khz.
Figure 1.B shows in simplified way the composition of the IR receiver and the way it filters all the source of light except the the 40Khz IR signal.
Ultrasonic Sensors
Ultrasonic sensors
use sound waves rather than light, making them ideal for stable detection of
uneven surfaces, liquids, clear objects, and objects in dirty environments.
These sensors work well for applications that require precise measurements
between stationary and moving objects.
Ultrasonic Distance Sensor provides range from
very short (2 Centimeters) to long-range (5 Meters) for applications in
detection and ranging. The sensor provides precise and stable non-contact
distance measurements from about 2 cm to 5 meters with very high
accuracy.
The ultrasonic sensor can easily be interfaced
to microcontrollers where the triggering and measurement can be done using two
I/O pin. The sensor transmits an ultrasonic wave and produces an output pulse
that corresponds to the time required for the burst echo to return to the
sensor. By measuring the echo pulse width, the distance to target can easily be
calculated.
Specifications
- Power supply :5V DC
- Quiescent current : <2mA
- Effectual angle: <15°
- Ranging distance : 2cm – 500 cm
- Resolution : 0.3 cm
Features
- Range: 2 cm to 5 m.
- Accurate and Stable range data
- Data loss in Error zone eliminated
- Modulation at 40 KHz
- Triggered externally by supplying a pulse to
the TRIG pin
- 5V DC Supply voltage and Current - <20mA
- Can communicate with 5 V TTL or 3.3V CMOS
microcontrollers
- Echo pulse: positive TTL pulse, 87 µs minimum
to 30 ms maximum (PWM)
-->> Citation:http://www.sunrom.com/sensors/distance/ultrasonic-distance-sensor-pwm-out?sunid=481fd139a0966b09e95fe2d68784a5ab
WEEK 4 => 27Aug - 2Sep
A white cane is used by many people who are blind or visually impaired.
§ Long Cane: This "traditional" white cane, also
known as a "Hoover" cane, after Dr. Richard Hoover, is designed
primarily as a mobility tool used to detect objects in the path of a user. Cane
length depends upon the height of a user, and traditionally extends from the
floor to the user's sternum. Some organisations favor the use of much longer canes.
§ Guide Cane: This is a shorter cane - generally extending from
the floor to the user's waist - with a more limited mobility function. It is
used to scan for kerbs and steps. The guide cane can also be used diagonally
across the body for protection, warning the user of obstacles immediately
ahead.
§ Identification
Cane (or Symbol
Cane in British English): The ID cane is used primarily to alert
others as to the bearer's visual impairment. It is often lighter and shorter
than the long cane, and has no use as a mobility tool.
Kiddie Cane:
This version works the same as an adult's Long Cane but is designed for use by
children.
History
In 1921 James Biggs, a photographer from Bristol who became blind after an accident and was uncomfortable with the
amount of traffic around his home, painted his walking stick white to be more
easily visible.
In 1931 in France, Guilly d'Herbemont launched
a national white stick movement for blind people. On February 7, 1931, Guilly
d'Herbemont symbolically gave the first two white canes to blind people, in the
presence of several French ministers. 5,000 more white canes were later sent to
blind French veterans from World War I and blind civilians.
-->> Citation: http://en.wikipedia.org/wiki/White_cane
Wand for the blind
with sensor
A smart innovation in
wand for the blind.no more classic long stick. This wand is working by sensing
the objects around.it can recognize the objects by distance sensor without pole
which means easy to hand carry. This wand can help working utilizing the well
developed tactile sense of the blind man.it will raise an alert for the blind
to avoid any obstacles and allow time to be ready in advance.
-->> Citation: http://www.tuvie.com/wand-for-the-blind-with-sensor/
Munivo guide for the blind
How it works:
Ultrasound technology (remote sensing) forms the base of
this trouble-free and handy device. Munivo sends information to the electronic
control unit after measuring distance between the subject and the potential
obstacles that is carried on two axes, X and Y. Moving on two axes; signals are
transmitted to the subject, in the form of spheres through roller-type
electromagnetic actuators, hence, giving instructions to the topic to steer
clear of any hindrance. Actuators placed in the silicon films which are
directly in contact with the palm gets control signals, after the device
processes signals from sensors.
-->> Citation: http://www.designbuzz.com/munivo-handheld-navigation-device-directs-the-blind-to-walk-free/
WEEK 3 =>20 Aug - 26Aug
WHAT?
What
am planning to do is to help the blind people to make their life more easier
and not letting them to feel they are different or they can’t walk freely.
WHEN?
When
did I come up with this idea? Actually there is no specific time , every day
when I walk in the street I can see some visually
impaired people walking in the
street and crossing the road with help of people or walking alone with some
difficulties but at the same I can feel how difficult it is ,so I was planning
one day I could help them. I took the advantage that am a student of Medical
Electronics and at the same time to develop the blind stick to a magic stick
that can make their life more easier In Shaa Allah.
HOW?
How
am going to develop the blind stick? Am planning to build a stick that contains
multi sensors that can sense obstacles and holes in the ground and stairs, by
using a stick connected to for wheels ,so when the senor detect any obstacles
it will change the direction to the opposite side by moving the wheels.
WEEK 2=>13 Aug - 19Aug
At the beginning of this
week I started to search for a topic for my FYP and at the same time to find
the perfect supervisor who has the great experience that he can assist me in my
project and at the same time to learn from his experience and his thoughts
which I can gain from him.
The topic I have chosen is
(Development of Multi Sensor Blind Stick).
And my supervisor is Dr. Zulkhairi
bin Mohd Yusof.
Dr. Zulkhairi
has accepted to guide me in my FYP and at the same time I will do my best to
gain from him and to be succeeded in my FYP In Shaa Allah.
WEEK 1 =>6 Aug - 12Aug
Welcome to my final year project BlogSpot... In this blogger am going to
show my progress in developing multi sensor blind stick.
In this week am going to introduce myself.
Muhammed Sharif Alshaikh Idris . Studying bachelor of Medical
Electronics Engineering in University Kuala Lumpur (British Malaysian Institute).
From Sudan.
Please feel free to comment because it will help me a lot and I will
accept any advice or any ideas.
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