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Nokia 3310 Lcd
Thermometer using DS18B20
source:
ivica.novakovic - [website]
Use parts of an old or broken mobile phone? Why
not!
One useable part of a mobile phone is its LCD,
which can be used in many applications where we
need data visually presented.
Nokia 3310 has a LCD with 84*84 dots, that isn't
that hard to get and can be very useful in DIY
(do it yourself) electronics.
This page describes a device I designed to test
such a display and turned out to be the circuit
that I am proud to share with you. Since my
motto is “simplicity in construction”, with a
few parts you will be able to create a
relatively accurate and visually appealing
thermometer.
Technical
characteristics :
-
Voltage
....................... 3 -
3.3 V
-
Range (1)
....................-55 do
125' C
-
Min. temp. step ............
0,1 ' C
-
Max. error
................... +/- 0,5
' C
-
Max. resolution
............. 0,0625 ' C
-
Temp. refreshed every....
1,2 sec.
-
Dimensions
................... 40 * 38
mm
-
2 modes of display
.........normal/inverse
-
Llcd
.............................
84*48pixela
-
Amperage
(2)................. 0,2 mA
- 0,8 mA
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Range of -55 to 125°C is
possible if ONLY the sensor is
in that area not the whole
device!
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Amperage of the device varies
because of the conversion of
DS18B20 (measuring the
temperature and reading the
measured temperature), that
lasts about 700ms and at that
time the device uses 0.8mA, for
the next 500ms the device is in
“sleep” mode and uses 0.2mA.
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The LCD supports two modes of
operation (normal and inverse), the
jumper placed on the back of the
device is used for changing modes.
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Negative temperatures are given a
“minus”, the bar shows temperatures
normally but with an added minus.
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In this picture I charged the device
with a 3.6V lithium battery. Do not
use a greater voltage then this
because the Nokia 3310 LCD works
with 2.7 to 3.3V!!! Careful!
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Lcd
First we need to extract/salvage the
LCD from the Nokia 3310 mobile
phone. Be extremely careful and
patient during this process, because
as you know the display is just a
thin piece of glass that is very
sensitive.
There is an 8 pin connector on the
back of the display, in our case
it's glued to the glass (Nokia 3210
has “rubber” connectors so this one
is much easier to use). This is a
Phillips PCD8544 display, it can be
easily found on the net if you want
more information about it.
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PCB
The second step is making the board
which is small and isn't that
difficult to make. Pay close
attention while gluing the plastic
edges on the board because they will
be holding your LCD. Double check
connector positions before gluing.
In the bottom corners I glued two
plastic separators so the LCD leans
on them and not the solder points.
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Layout of
elements
On the back side we can see the
layout of elements, they aren't hard
to find and there aren't that many
of them.
I placed the temperature sensor
DS18B20 in a socket for testing
purposes, it is also possible to
connect the sensor at a distance by
adding wire (I haven't tested 1 wire
sensors at a distance yet).
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pcb
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elements/components
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If by any chance the contrast isn't to
your liking, it can be changed during
the programming of Pic12F629, in the
program location D2h. the current value
A9h is the one I use with my LCD and
don't know it will be for other LCDs.
The value can be set to anything between
80h and FFh, 80h being minimum contrast
and FFh maximum.
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Since I have noticed
that there is a problem
with programming these
microcontrollers you
should read the short
how-to for programming
PIC12F629/675
microcontrollers.
This device was just a
test and I hope to have
many more circuits that
utilize this LCD soon
because I'm very fond of
its easy implementation.
If you have any
difficulty in making
this device, feel free
to
mail me.
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Projects
