Datasheet

24
CIRC-09
.:Light:.
.:Photo Resistors:.
Whilst getting input from a potentiometer can be useful
for human controlled experiments, what do we use
when we want an environmentally controlled
experiment? We use exactly the same principles but instead
of a potentiometer (twist based resistance) we use a photo resistor (light based
resistance). The Arduino cannot directly sense resistance (it senses voltage) so we
set up a voltage divider (http://ardx.org/VODI). The exact voltage at the sensing
pin is calculable, but for our purposes (just sensing relative light) we can
experiment with the values and see what works for us. A low value will occur when
the sensor is well lit while a high value will occur when it is in darkness.
Wire
Photo-Resistor
x1
560 Ohm Resistor
Green-Blue-Brown
x1
2 Pin Header
x4
CIRC-09
Breadboard Sheet
x1
Green LED
x1
10k Ohm Resistor
Brown-Black-Orange
x1
Arduino
pin 13
LED
resistor
(560ohm)
gnd
(ground) (-)
+5 volts
photo
resistor
resistor
(10k ohm)
Arduino
analog
pin 0
.:download:.
breadboard layout sheet
http://ardx.org/BBLS09
.:view:.
assembly video
http://ardx.org/VIDE09
WHAT WE’RE DOING:
Parts:
The Internet
THE CIRCUIT:
Schematic