2. AGENDA
INTRODUCTION OF DAC
TYPES OF DAC
DAC CONVERTER (DAC 0808)
INTERFACING DAC TO PIC
INTRODUCTION ABOUT SENSORS
SENSOR INTERFACING WITH PIC
LDR AND LM75
CONCLUSION
3. INTRODUCTION TO DAC
The DAC is widely used to convert digital pulses into
analog signals
4. PARAMETERS OF DAC
RESOLUTION
It is defined as the smallest change that can occur in analog
output as a result of change in the digital output
FULL SCALE OUTPUT
The maximum output available from a DAC ( all binary
inputs are one)
MONOTONICITY
A DAC is said to be Monotonic if its output increases as the
binary input is incremented from one value to the next
8. DAC OUTPUT (INTERFACING OF DAC TO PIC)
Two DAC Output s are easily added to a PIC with
MAX 518 (8pin DIP)
9. INTRODUCTION
Whether or not the Embedded Microcontroller is a
Human Interface, it will certainly interface with the
physical world.
Output Transducers converts electrical variables to
physical.
Some simple sensors, The Micro switch
10. LDR INTERFACING WITH PIC
(1) LDR:
Sensitivity depends on
intensity of light.
Resistance of LDR
decrease with increase
in intensity of light and
vice-versa.
11. LDR INDICATIVE OUTPUT VALUES
ILLUMINATION
(Lux)
R LDR
ohms
Vo
Volts
DARK 2M 5.00
10 9k 2.36
1000 400 0.19
12. NTERFACING A TEMPERATURE SENSOR
National Semiconductor’s LM75 combines an
analog temperature transducer, an analog to
Digital Converter(9 bit) and an I2C bus interface
Temperature range covered -25 to 100 C
16. You can download this PPT from the
Website: sasidharansrinivasan0197.blogspot.in
Editor's Notes
LDR is a device whose sensitivity depends upon the intensity of light falling on it. When the strength of the light falling on LDR increases the LDR resistance decreases , while if the strength of the light falling on LDR decreased resistance incresed.
In the time of darkness or when there is no light, the resistance of LDR is in the range of mega ohms, while in the presence of light or in brightness in decrease by few hundred ohms.