Squeezing
(Force Sensitive Resistors)
The Pieces
The Theory & Code
Force Sensitive Resistor
(Interlink 402)
x1
10k ohm Resistor
(brown-black-orange)
.: for a tutorial with all the technical details visit: http://tinyurl.com/p7kueo :.
x1
(ladyada.net)
Testing
This sensor is very easy to test, simply use a multi-meter. Attach
one probe to each pin, and measure resistance. Squeeze the sensor
to see the resistance change.
Green LED
x1
560 ohm Resistor
(green-blue-brown)
x1
The Schematic
Arduino
pin 9
Force Sensitive Resistor (FSR)
An FSR is a great sensor, which is easy to implement. It is very
similar to a potentiometer, except rather than varying its resistance
in relation to shaft position its resistance varies with pressure. The
resistance is high (infinite) when there is no pressure and low when
the pressure is high (250 Ohm with 10 kg force).
Test Circuit
Cut out the breadboard layout sheet below and make the circuit on
your breadboard. Next download the code available here:
http://tinyurl.com/l7u7co. Upload to your board, squeeze the
sensor and watch as the LEDs brightness changes. Also if you would
like to see raw values, open the serial monitor and set it to 9600.
+5 volts
Arduino
FSR
analog
pin 2
Technical Details
.: Interlink 402 Datasheet: http://tinyurl.com/lyed9b :.
LED
(light
emitting
diode)
Resistance vs. Pressure
resistor
resistor
(560ohm)
(10kohm)
gnd
force
0g
20 g
100 g
1 kg
10 kg
FSR Resistance
infinite
30 k ohm
6 k ohm
1 k ohm
250 ohm
(ground) (-)
The Circuit
The Layout Sheet
A B C D E
F Gto
H Gnd
I J
1
to 5v
2
1
2
3
3
4
4
5
5
6
6
7
7
8
8 ohm
10k
9
9
10
10
11
to analog
2
11
12
15
16
17
18
12
5mm
LED
13
14
longer
lead
13
to
14
+
-
pin 9
15 ohm
560
16
17
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
CIRC-17
26
26
Squeezing
27
27
(Force Sensitive28
Resistors)
28
29
29
30
30
A B C D E
.: Instructions: print out, cut out, get making :.
.: for more details visit: http://tinyurl.com/ncoq4g :.
F G H I
J