24 Hour Data Logger - Elenco Electronics SNAP CIRCUITS XP SCXP-50 Instruction Manual

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Table Of Contents

Table of Contents

Project B21

This circuit is a data logger, which calculates the cost

of electricity used by a lamp or other light source in one

day. You will be able to modify the program to test it

with a short time period, then restore it to the original

program to measure the energy cost over a full day.

Use the circuit from project B19 (Data Logger). Turn on

the slide switch (S1). Load the program "Data Logger

24 Hour" into the microcontroller (U21) using

instructions in project B1.

immediately after download.

The microcontroller measures the amount of light on

the photoresistor (RP), at start and every hour for 24

hours. Data is stored and sent to the computer every 6

seconds, but can also be accessed at any time. Place

the circuit near a lamp or other electric light. Point the

photoresistor at the source to be measured and shield

Optional:

it from daylight and other light sources. Turn on S1 and

test circuit. The red LED should be on for 6 seconds

then off for 6 seconds when the source is on. The

green LED will be on for 6 seconds then off for 6

seconds when the source is off. If ambient light

interferes try using a tube from a roll of toilet paper to

shield the photoresistor (RP) from other light sources.

Data can be taken for 24 hours. When memory is full

Turn switch S1 off

both LEDs will blink.

You may turn off the data logger (S1) and reconnect it

to your computer at any time to inspect data gathered

thus far, but time from that hour may be lost. Access

the data using the terminal window as described in the

Data Logger project.