International Journal of Engineering Trends and Technology (IJETT) – Volume 26 Number 4- August 2015
Smart Pen
Sidvita.U.Hegde#1, Aman.S.Malkar*2
Student, Information Technology, Fr. C. Rodrigues Institute of Technology
Student, Information Technology, Fr. C. Rodrigues Institute of Technology
Mumbai, India
Abstract—We often waste time searching for a particular
paint or color for making paintings, cards or charts.
Sometimes people might want a specific shade of a color
which might not be possible to generate easily using the
available colors. Apart from this, brushes need to be cleaned
repeatedly before using a new color. We propose a pen
(smartpen) that can change its color depending on the color of
the object it touches or the shade of the color the user
the LCC8 package and the special JENCOLOR® interference
filter technology, the MRGBiCS is long-term stable over the
entire product lifetime and resistant to external influences
such as temperature drifts. The MRGBiCS operates within
temperature ranges of -20°C to 100°C.
Keywords — colour changing pen, smart pen.
▪ General color detection, checks and control options
▪ Portable color reader for consumer and industrial
▪ Sorting tasks, color teaching.
Using of paints, brushes and the frustration caused due to the
unavailability of a particular colour while performing
everyday tasks like painting, card making etc. can be avoided
with the help of the proposed system. The proposed system on
coming in contact with an object senses its colour, and the
RGB cartridge present in the pen jets out the same colour.
Apart from this the shade of a particular colour can be varied
with the help of pressure sensors present at the middle part of
the pen. On the basis of pressure applied the pen adjusts the
amount of lighter or darker components and provides one with
the particular colour.
▪ JENCOLOR® interference filter technology
▪ High transmission
▪ No aging of the filter
▪ High temperature stability
▪ High signal frequency
▪ Reduced cross talk
▪ Compact size (diameter of the optical sensitive surface
approx. 2 mm)
▪ LCC package
▪ EU RoHS conformity2
2. Pressure knob
Pressure knob is like a button that will help the user to select
the shade of the color he wants. The knob has two modes of
operation. If the user wants darker shade, he has to long-press
1. Jencolor RGB color sensor
the knob and if he wants a lighter shade he has to burst-press
in short bursts. The knob is synchronized with the pressure
Color sensors detect the color of a surface. The sensors cast
sensor which in turn is connected to the microcontroller.
light (red, green, and blue LEDs) on the objects to be tested,
calculate the chromaticity coordinates from the reflected 3. Pressure Sensor
radiation and compare them with previously stored reference The LPS22HB is an ultra-compact piezo resistive absolute
colors. If the color values are within the set tolerance range, a pressure sensor which functions as a digital output barometer.
switching output is activated.
The device comprises a sensing element and an IC interface
The JENCOLOR® sensors are made of 19x3 photodiodes
which communicates through I2C or SPI from the sensing
integrated on-chip (special PIN silicon technology with
element to the application.
advanced sensitivity). The diodes are aligned as segments of a
multiple-element hexagonal matrix structure with the diameter
of 2 mm. The design as Si-PIN photo diodes allows signal
frequencies up to the MHz-range. In order to achieve minimal
• 260 to 1260 hPa absolute pressure range
cross talk between the photodiodes the individual sectors are
• Current consumption down to 4 µA
separated from each other by additional structures. Based on
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International Journal of Engineering Trends and Technology (IJETT) – Volume 26 Number 4- August 2015
• High overpressure capability: 20x full-scale
• Embedded temperature compensation
• 24-bit pressure data output
• 16-bit temperature data output
• ODR from 1 Hz to 75 Hz
• SPI and I²C interfaces
• Embedded FIFO
•Interrupt functions: Data Ready, FIFO flags, pressure
• Supply voltage: 1.7 to 3.6 V
• High shock survivability: 22,000 g
• Small and thin package
• ECOPACK® lead-free compliant
The LPS22HB is a high resolution, digital output pressure
sensor packaged in an HLGA full mold package. The
complete device includes a sensing element based on a piezo
resistive, Wheatstone bridge approach, and an IC interface
which communicates a digital signal from the sensing element
to the application.
Sensing element
An ST proprietary process is used to obtain a silicon
membrane for MEMS pressure sensors. When pressure is
applied, the membrane deflection induces an imbalance in the
Wheatstone bridge piezo resistances whose output signal is
converted by the IC interface.
I2C interface:
The complete measurement chain is composed of a low-noise
amplifier which converts the resistance unbalance of the
MEMS sensors (pressure and temperature) into an analog
voltage using an analog-to-digital converter. The pressure and
temperature data may be accessed through an I²C/SPI
interface thus making the device particularly suitable for
direct interfacing with a microcontroller. The LPS22HB
features a Data-Ready signal which indicates when a new set
of measured pressure and temperature data are available, thus
simplifying data synchronization in the digital system that
uses the device.
Working mode :
FIFOThe LPS22HB embeds a 32-slot of 40-bit data FIFO to store
the pressure and temperature output values. This allows
consistent power saving for the system, since the host
processor does not need to continuously poll data from the
sensor, but it can wake up only when needed and burst the
significant data out from the FIFO. This buffer can work
according to seven different modes: Bypass mode, FIFO
mode, Stream mode, Dynamic Stream mode, Stream-to-FIFO
mode, Bypass-to-Stream and Bypass-to-FIFO mode. The
FIFO buffer is enabled when the FIFO_EN bit in
CTRL_REG2 (11h) is set to '1' and each mode is selected by
the FIFO_MODE[2:0] bits in FIFO_CTRL (14h).
Programmable FIFO threshold status, FIFO overrun events
and the number of unread samples stored are available in the
FIFO_STATUS (26h) register and can be set to generate
dedicated interrupts on the INT_DRDY pad using the
goes to '1' when the number of unread samples
(FIFO_STATUS(FSS5:0)) is greater than or equal to
WTM[4:0] in FIFO_CTRL (14h). If FIFO_CTRL(WTM4:0)
is equal to 0, FIFO_STATUS(FTH_FIFO) goes to '0'.
FIFO_STATUS(OVRN) is equal to '1' if a FIFO slot is
overwritten. FIFO_STATUS(FSS5:0) contains stored data
levels of unread samples; when FSS[5:0] is equal to '000000'
FIFO is empty, when FSS[5:0] is equal to '100000' FIFO is
full and the unread samples are 32. To guarantee the switching
into and out of FIFO mode, discard the first sample acquired.
Factory calibration
The IC interface is factory calibrated at three temperatures and
two pressures for sensitivity and accuracy. The trimming
values are stored inside the device in a non-volatile structure.
When the device is turned on, the trimming parameters are
downloaded into the registers to be employed during the
normal operation which allows the device to be used without
requiring any further calibration.
Fig. 1 Spectrum Characteristic of RGB sensor
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International Journal of Engineering Trends and Technology (IJETT) – Volume 26 Number 4- August 2015
-16GB flash memory
-6-20V unregulated power supply
-Each of the 14 digital pins on the Nano can be used as an
input or output.
Fig. 2 Arduino Nano
4. RGB color cartridge
The RGB color cartridge will form the color as directed by the
<microcontroller> depending on the input of the color sensor.
The user can further change the shade of the color depending
on their need (dark/light) with the help of the pressure knob.
The pressure knob is connected to the pressure sensor which
allows the precise shade to be selected. Darker shades are
obtained by mixing black color with the current color
selection and brighter shades are obtained by mixing white
with the current color.
A color sensor is present at the apex of the pen. When this
comes in contact with an object, it detects the color. This
analog value is then sent to a microcontroller which converts
it into a digital value. The value from the microcontroller is
sent to the system using the wifi module embedded into it.
The value is then compared with the already existing values.
On finding a match, the same RGB value is used to inject the
specific ink.
A pressure sensor is present as show in the figure. Based on
the pressure applied the color changes shade. The value from
the pressure sensor is sent to the Arduino and based on the
value, it is either darkened by mixing black ink or lightning it
by mixing white ink.
5. ESP8266 wifi module
ESP8266 is an impressive, low cost WiFi module suitable for
adding WiFi functionality to an existing microcontroller
project via a UART serial connection. The module can even
be reprogrammed to act as a standalone WiFi connected
device–just add power! The feature list is impressive and
includes: 802.11 b/g/n protocol Wi-Fi Direct (P2P), soft-AP
Integrated TCP/IP protocol stack.
6. Arduino Nano
The Arduino Nano is a small, complete, and breadboardfriendly board based on the ATmega328 (Arduino Nano 3.x)
orATmega168 (Arduino Nano 2.x). It has more or less the
same functionality of the Arduino, but in a different package.
It lacks only a DC power jack, and works with a Mini-B USB
cable instead of a standard one.
ISSN: 2231-5381
Fig. 3 Proposed Model of Smart Pen
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International Journal of Engineering Trends and Technology (IJETT) – Volume 26 Number 4- August 2015
In this paper, we have proposed an enhancement to the
traditional pen. The pen prototype, if implemented, could be
useful for various purposes. People would not have to waste
time to clean their brush or to find a color or spend time
trying to mix various colors to obtain a particular shade. This
pen can be carried along to scan whichever color we like or
intend to use and start writing or painting along, without
having to look for a brush or a color palette.
_St art_Guide_v_1.0.4.pdf
[7]Ch Srikanth, D S Pradeep M and Sreeram Charan K, "Smart Embedded
Medical Diagnosis using Beaglebone Black and Arduino" International
Journal of Engineering Trends and Technology (IJETT),Volume.8,No.1,pp.
43-48,Feb 2014.
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