Sparkfun Electronics RedBoard - Circuit 6: Photo Resistor; Photo Resistor Functionality; Circuit 6 Assembly Guide

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Circuit 2
So you’ve already played with a potentiometer, which
varies resistance based on the twisting of a knob. In
this circuit, you’ll be using a photo resistor, which
changes resistance based on how much light the
sensor receives. Since the RedBoard can’t directly
interpret resistance (rather, it reads voltage), we use a
voltage divider to use our photo resistor. is voltage
divider will output a high voltage when it is getting a
lot of light and a low voltage when it is not.
Photo Resistor
PARTS:
Wire
6
X
CIRCUIT #6
6
LED
1
X
330Ω
Resistor
1
X
Photo Resistor
1
X
10KΩ
Resistor
1
X
IOREF
RESET
RESET
7-15V
SCL
SDA
AREF
GND
13
12
~11
~10
~9
8
7
~6
~5
4
~3
2
1
0
TX
RX
13
3.3V
5V
GND
GND
VIN
A0
A1
A2
A3
A4
A5
POWER
ANALOG IN
DIGITAL (PWM~)
ON
ISP
TX
RX
LEARN. SHARE. HACK.
PIN 9
PIN A0
Resistor (330 ohm)
(Orange-Orange-Brown)
GND
(Ground)
Resistor (10K ohm)
(Brown-Black-Orange)
LED
(Light-Emitting Diode)
Photocell
(Light Sensitive Resistor)
RedBoard
5 volt