Sensors
Technology /
Property sensed
Details
Price
electrical properties
microswitches,
pressure & contact
sensors
many sizes and current ratings available, many with levers for contact sensing, SPDT most
common, make your own with wire, foil springs etc.
artist constructed
switches
special action, tilt, vibration, wind switches can be made with wire, springs cloths pins etc. see Radio Shack
literature for ideas. Use gold plated wire for reliable contacts, anodized or steel wire for deliberately
“noisy” contacts. Anything conductive can be used as a switch type sensor
push-button switches
magnetic reed switches
magnetism
current
$ .50 -2.50
each
Many sizes including miniature, pc board mounted - come with different pressure
specifications
Check the action before buying, some require a lot of force, are less dependable. Small PC
board mounted switches are cheap and reliable
$ .20 - 1.00
part A is the switch, part B is a magnet, requires a fairly close gap between switch and
magnet.
$ 1.00 - 3.00
Any coil can be used as a magnetic sensor for a moving magnet. Hall Effect sensors are
cheap and widely used for rotation, position sensing. On-off and analog varieties. Check
Digikey.com
$ 1.00 - 3.00
Current can be sensed easily with a resistor, which converts the current to a voltage
pressure - force / gas & liquid pressure / touch
pressure / force sensing
resistors
strain gauges
(bend & pressure
sensors)
gas pressure
touch / capacitive touch
sensor
sandwich a piece of conductive foam between two pieces of aluminum or copper. resistance varies with
pressure, many commercial types available, check for surplus "dance" computer game pads, force sensing
resistors QTC, Interlink are two brands,
many commercial models available or fabricate your own with graphite and plastic. See Radio Shack
pamphlet, commercial models expensive, and highly accurate, see Jameco bend sensor $9, Mattel
Datagloves contain five bend sensors, rough ones easy to construct.
Inexpensive chips ($15) are available from digikey.com others for pressure sensing - can be used as musical
instrument controllers
See Quantum chips at digikey.com. QT113 is a simple model. Also simple switches may work for some
applications.
liquid level
liquid (usually water)
make your own with two probe wires and a resistor, kits available, also sensed with
capacitive type "touch" sensors (Quantum chips)
light, motion
cadmium sulfide
variable resistors
wide range of resistances and light levels available, change resistance with light level,
closest to color range of human eye
$.10 - .50
silicon solar cells
generate current in proportion to light intensity. polarized - connections
photo-transistor
photo-diode
photo-scr
photo-triac
Work in similar ways to their semiconductor family members. Typically light will gate
these devices on. Can be used for light modulated remote controls and beam interrupt
systems. Many in infra red region invisible to human eye
$.50 - 4.00
infrared LED’s
used in conjunction with above for infrared sensors, may use much higher current than
$.50 - 2.00
$1.00 - 10.00
visible LED, up to 100 m A
light to voltage
light to frequency
PIR (passive infrared)
human
motion detectors
many circuits and kits available, see the TSL230, 260 chips; light to voltage and light-tofrequency converters
$3.00 – 12.00
Wide angle motion sensing but no quantification of how much motion or how close motion
is.
Many low and line voltage models with built-in relays at hardware stores,
For low voltage check electronics123.com, jameco.com and surplus catalogs, for line voltage
check Home Depot, hardware stores. It is also possible to create this function with
photoresistors and software (check for changes in values).
$5.00 - 20.00
proximity, ranging, rotation, position
slide potentiometers
joystick
proximity / infrared,
distance measuring
linear motion slide pots. as used in sound mixing boards, less rugged than round pots
dirt on slides causes uneven action
$ 1.00 - 5.00
uses either 2 or 4 pots , for 2 axis control, check surplus catalogs, tear apart or rewire
game controllers
$ 2.00 - 20.00
Sharp makes several inexpensive ranging sensors. They output a voltage proportional
to distance, see Digikey catalog. Can be used for Theramin like controls, sensing
audience presence, distance
$12 - 25
proximity / sonar
distance measuring
Devantech SR04, SR08, Parallax Ping, Polaroid (obsolete?), ranges to 10-12' wider sensing cones than
infrared,
rotation
Use DC motor as to generator for output voltage; potentiometers, digital encoders , motors sold with
encoders
tilt,
mercury switches (avoid), Sharp 2 axis tilt sensor $2.00, low G accelerometers ADXL202, ADXL311,
inclinometers, many modules available, see Parallax.com
position / rotational /
potentiometer
potentiometers are cheap and good for angular position sensing, also slide pots for linear sensing, mercury
switch, Sharp tilt sensor, "ball in a cage" types. Digital encoders are used with servo and stepper motor
systems, can also be used as input devices / rotation sensors.
position / rotational /
encoder
Encoders often look superficially like potentiometers but send digital pulse trains in response to rotational
motion. Mechanical ones are cheap, optical units are more reliable and more expensive. Usually require
some interface circuitry.
position / linear
slide potentiometers are good for low resolution. Check LVDT for high precision (and prices).
digital compass
several levels of chips from $10 - $70 see digital compass circuits in Nuts and Volts magazine,
see parallax.com
sound
Various microphones with op-amp circuits, many kits available. Piezo disks can also be used for sound and
vibration sensors, inexpensive at Radio Shack, qualitykits.com
vibration
Use piezo disks from Radio Shack, don't buy ones with built-in oscillators ("alert beepers"), can also be used
as strain gauge type of sensor $1-3
tilt / switches,
ball bearing, mercury
tilt / accelerometers
Mercury switches, ball bearing switches, some with several leads for directional tilt sensing
$ 1-5
prices from $20, senses gravity and acceleration, can be used for sensing orientation of an object in
relationship to direction of gravity, look for "one chip" models, see parallax.com, search for accelerometer,
low G models are more sensitive - look for 2 - 5 G's, see ADXL202, 311
biomedical
heartbeat
galvanic skin potential
IR heartbeat sensors, see especially the TAOS light-to-frequency and light-to-voltage sensors (around
$5.00), also Ramsey EKG kit $35 (marginal for artist’s use), EKG schematics on the internet
skin potential, simple op amp circuits, schematics on the web
brain waves,
biofeedback
breath
various other
EEG schematics available, see “Biomuse”, really expensive $10K
strain gauge, flex sensors, cheap CO2 sensors available ($30)
eye tracking systems, infrared imaging, virtual reality gear, chemical sensors
integrated systems / input - output boxes for desktop computers
high level integrating
sensing
Very Nervous System, Biomuse, virtual reality systems,
input / output boxes
for desktop computers
EZIO, ICube , Teleo system, Labjac, various input / output cards for windows computers, check
www.cycling74.com for hardware that works with Max software. Search for "data capture".
kit manufacturers
PAIA
Wonderful, value priced and well designed electronic music kits, many oriented towards electronic music
and MIDI. A Theramin based sensor, and a MIDI-to-control-voltage output box could be used with many
other projects
Velleman Kits
European manufacturer of popular electronics kits. Many “functional block” type kits such as a DC control
voltage to 120 v light dimmer, and a DC to Pulse Width Modulator kit. Reasonably priced.
Ramsey
Lots of moderately priced radio transmitter and other kits, EKG kit (marginal for artists projects)
DIY Kits
Value priced kits ($10 - 30) many of which could be used for artist's projects. power supplies, light
dimmers and audio amplifiers among many others
kit web sites
www.qkits.com, www.oatleyelectronics.com, www.dckits.com, kitsrus.com, webtronics, www.kitsusa.com,
paia.com
sensor outputs
voltage
many sensors output some kind of voltage with 0-5 volts being an especially popular range. If the voltage is
too small or too large an operations amplifier (op amp) can be used to scale the voltage. Read sensors
voltages with a A /D converter input
current /
resistance
These sensors either act as resistors or as current sources. They can be converted to voltages with the use of
a resistor bridge and then read with an A/D converter OR with RCtime for microcontrollers like the Basic
Stamp, which lack A/D inputs.
pulse width
Some sensors output a signal that is encoded in a pulse width (or a frequency). Various microcontroller
commands must be used to either measure a pulse width or count the frequency over a specific time
duration. On the Basic Stamp the Pulsin and Count commands are useful for this function.
synchronous
serial
Synchronous serial is a digital format that requires (usually) three digital lines to the sensor or device.
These are clock, chip select and data out, (sometimes data in, too often on the same line). Read synchronous
serial with the Shiftin command in BASIC.
I2C
I2C is another digital protocol. Many microcontrollers have specific commands to read this format.