DS18S20 Dual Temperature Meter


DS18S20 Dual Temperature Meter


  DS18S20 Dual Temperature Meter Component List:

1x 2×16 LCD with Backlight
1x 16×1 LCD Female Header Connector
1x 16×1 LCD Male Header Connector
1x
Programmed PIC16F628
2x DS18S20 1-Wire Digital Temperature
Sensor
1x 100nF Capacitor
1x 10K Pot (LCD Contrast)
1x 10K Resistor
2x 1K Resistor
1x 10 Resistor
1x LM7805 Voltage Regulator
1x Tactile Switch (Display Modes)
1x 2-PIN Male Header Connector
1x 4-PIN Male Header Connector

  Technical
Specifications:

Temperature Measurement:

-55 to 125°C (-67 to 257°F)
Accuracy: 0.5 °C / 1 °F
Supply
Voltage:
7.5 –
15V
Power Consumption: 8mA (when LCD backlight
is turned off)

DS18S20 Dual Temperature Meter Schematic

DS18S20 Dual Temperature Meter



 

This is
a simple to build DS18S20 dual temperature meter
that allows to measure temperature in two different
locations at the same time. The meter is built with
very few components thanks to the use of PIC16F628
microcontroller and 2×16 character LCD display. It is like a small computer that can be customizable
by upgrading its hex firmware.

DS18S20 Dual Temperature Meter

DS18S20 dual temperature meter uses two very exciting DS18S20
digital temperature sensors that come in convenient
TO92 package. Unlike regular sensors where temperature
readings are passed as varying voltage, DS18S20
passes temperature information in a digital format
as data. This brings many new possibilities and
enables to pass temperature information over much
longer distances just over a two wire cable. With
this capability temperature can be measured in different locations
at the same time away from the main circuit
board. With regular temperature sensors that rely on the voltage cables must be as short as possible because
longer wire lengths introduce stray resistance and bring
unreliable readings.

DS18S20 Dual Temperature Meter

Another great feature of DS18S20 sensor is that
it doesn’t require any calibration at all, while
providing 100% accuracy out of the box. That means
that you just plug it in and there’s no need spending time recalibrating temperature readings. This is all due thanks
to the nature of sending information in a digital
format. In fact DS18S20 is just like a computer
connected to the network that has a unique serial
number identifier similar to an IP address. Multiple
DS18S20 sensors can send information simultaneously,
even over the same two wire bus cable. The two wires
provide 3-5V voltage supply to the sensors and they are
also used to pass data in two different directions.
If wires are very long so that voltage on DS18S20
sensors drops below 3V external 5V voltage supply can
be used with 1K resistor to power the sensors.

DS18S20 Dual Temperature Meter

Once PIC
microcontroller receives temperature information
it converts it into
both
Celsius and Fahrenheit values so that they can be
displayed on LCD display. DS18S20 dual temperature meter
is capable of measuring temperatures from -55 to 125
°C degrees Celsius (-67 to 257 °F Fahrenheit) with 0.5 °C / 1 °F accuracy.
If you just need to measure temperature in one
location you may just use one DS18S20 sensor and
PIC16F628 microcontroller will use just one sensor.

DS18S20 Dual Temperature Meter Customizations



 

Additionally
the way the temperature is displayed on LCD display
can be customized by pressing a tactile button.
Each selection is saved in non-volatile EEPROM memory
so that PIC remembers it even after the voltage
supply is disconnected. Requests for different display
styles are welcomed and can be upgradeable by simply
flashing PIC16F628 microcontroller with a new hex
firmware.

We have also plans
to release a temperature thermostat controller version
in the near future that will turn on/off devices
when certain temperatures are reached.
Thermostat controller can be used to turn on/off heaters, fans, air conditioning systems, etc.

DS18S20 Dual Temperature Meter PCB Layout


 

DS18S20 Dual Temperature Meter


DS18S20 Dual Temperature Meter Kit


 

DS18S20 Dual Temperature Meter

DS18S20 Dual Temperature Meter is available in a kit version at Electronics-DIY
store
. Please see the link for more details.


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