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PIR (PASSIVE INFRARED) DETECTOR USING ST7FLITE05/09/SUPERLITE

3 APPLICATION SPECIFICATIONS

3.1 CODE SIZE

Code size = 1.2 KBytes (with SCI implementation included)

=969 Bytes (without SCI Implementation, Code size less than 1K): Superlite can be used.

3.2 SIGMA-DELTA CONVERSION TIME

This is equal to the time taken to calculate a digital value after implementing the sigma-delta

algorithm.

Conversion Time= Timer interrupt time* Number of samples

Where Timer interrupt time = 52µs.

The AR timer is configured to generate an overflow interrupt every 52µs. In the Interrupt rou-

tine the software checks the ADC value and then decides the value for biasing signal (1-bit

DAC),

Number of samples = 1000 = Number of times the status of the DAC bit is decided. A software

counter is incremented each time the DAC status made LOW. The ADC is used as a compa-

rator in the application.

Conversion Time= (52µs)x(1000) = 52ms.

3.3 POWER CONSUMPTION

Input voltage must be greater than 9V. The values shown in table are given without relay and

MAX232 cicuitry

Table 1. Current consumption

3.4 DETECTION RANGE

Without Fresnel lens: 10” approx.

Sr.No.

Power LED

Heart Beat LED

Detection LED

Current Drawn (Normal conditions)

1

OFF

OFF

OFF

13mA

2

OFF

OFF

ON

26mA

3ON

OFF

OFF

26mA

4ON

OFF

ON

39mA

5ON

ON

OFF

39mA

6ON

ON

ON

51mA