Download Sensing Distance (SHARP GP2Y0A21YK)

Sensing Distance
(SHARP GP2Y0A21YK)
The Pieces
The Theory & Code
IR Distance Sensor
(Sharp GP2Y0A21Y)
x1
Infra Red Distance Sensor
An analog IR distance sensor is a really neat component. Simply connect +5v
and ground and a voltage proportional to the distance between the sensor and
an object in front of it will be returned (ranging from 0.4 volts at 80 cm to 3
volts at 10 cm). It really couldn't be simpler to use.
Converting to Distance
The voltage returned is not linear (see graph), however it can be converted to a
distance using some simple maths. There will be some variation between models
but here are a couple of equations that worked for us (results +-~5%)
Cable
(JST 3 pole)
x1
The Schematic
+5 volts
analog
pin
source: GP2Y0A21YK Datasheet
signal
gnd
+5v
Equations
From 10 bit A/D Reading to centimeters (5v supply)
distance = 12343.85 * (10bit reading)^-1.15
From Voltage Reading to Centimeters
distance = 27.86 (voltage reading)^-1.15
Arduino Code (5v)
float distance = 12343.85 * pow(analogRead(sensorPin),-1.15)
gnd
(ground) (-)
Technical Details
.: Full Datasheet: http://tinyurl.com/yh7chku :.
The Layout Sheet
A B C D E
F G H I
J
1
1
2
2
3
3
4
4
8
+5v
5
6
7
gnd
5
6
signal
The Circuit
7
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
to pin 21
analog 0
22
22
23
23
24
24
25
26
CIRC-20
27
Distance
28
(Sharp29
GP2Y0A21YK)
25
to 5v
26
27
28
to Gnd
29
30
30
A B C D E
.: Instructions: print out, cut out, get making :.
.: for more details visit: http://tinyurl.com/y9bjsjp :.
F G H I
J