A GENTLE INTRODUCTION TO HOW TO BUILD SENSORS:
by
Ricardo Climent 2001
A GENTLE INTRODUCTION TO HOW TO BUILD SENSORS:
by
Ricardo Climent 2001
I hope this workshop to be a gentle introduction about what kind of hardware (and software) can be used to build interfaces for musical human interaction. I could divide this area in three levels. Only level one will be covered today.
1) Creating an affordable collection of 'low voltage sensors'
(DIY)
2) Programming PIC microcontrollers. 
3) More serious chips... Programming Microprocessors.
TOP
MENU
_____________________________________________________
1) Creating an affordable collection of 'low voltage
sensors' (pricing from 0.35 pence to 80 pounds) and a 'CV to midi' converter
and using prefab kit interfaces commonly used for alarms and computer
interfaces. To mention a few.
CV SENSORS
| drum triggers | pressure sensors | infrared sensors |
| magnetic sensors | tilt switchers (mercurium etc) | pad sensors |
| piezoelectrics (many types) | laser diods | switches |
| temperature sensors | temperature sensors | slide resistors (linear & logar.) |
| knob variable resistors | photosensors (light sensitive) | Toggles |
| Your own body and a jack... |
COMPUTER INTERFACES and KITS:
| web cameras | graphic tablets (wacom Intuos pen tablet greta but not cheap) sens tilt and pressure | radio-like kits |
| magnetic-carbon kit | tilt switchers (mercurium etc) | FM transmiters /receivers encoders |
| serial interface components. | infrared sensor kit (typicla object counter) | microrobots with gears (we have built one for this!) It might sweep an Irisih harp. |
| Playstation-mat and a PSX-to-Gameport adapter and then use the joytick -object by J.Sarlo or the one in ggee. | CV to midi converters (A-192, paia.com) | modules and parts from synthesers like the A-100 by Doepfer. |
| fader and knob controllers (ControlFreak, Peavey 1600, Pocket control) |
check DIY cv to midi stuff by kenton
(how to build a suitable variable sensor check page 37 of the pdf manual online) |
sonars |
A-100
CV to midi:
The A-192 is a CV to MIDI converter that converts up to 16 CV inputs to MIDI controller data. This allows the analogue signals from modules such as LFO's and Envelopes to be converted to MIDI data that a sequencer or MIDI synth can use. Also the voltages generated from the Vocoder analysis (A-129/1) can be converted to MIDI data.
Module A-192
is a CV-to-MIDI interface that converts 16 control voltages in the range 0...+5V
into 16 MIDI controller messages. A-192 is the modular version of Pocket Control
with the 16 rotary controls replaced by 16 miniature jack sockets to process any
control voltages instead of the manually generated voltages of Pocket
Control.
MIDI messages appearing the MIDI Input are merged to the MIDI
controller messages generated by the A-192.
128 different assignments
(Presets) of the 16 CV inputs to MIDI controller messages are available.
Switching between the 128 presets takes place with an 8-pin DIP switch on the pc
board (permanently) or via incoming MIDI program change messages
(temporarily).
If none of the 128 factory presets is suitable new presets can
be made with the Pocket Control editor which is available for free on our web
site. Please look at the Pocket Control manual for details concerning the
available factory presets until the English manual for A-192 is
available.
The snapshot button transmits the 16 momentary states of the 16
inputs as MIDI controller messages.
For detailed information you may look at the A-192 user's guide.
Typical applications:
Theremin-to-MIDI (A-178 + A-192)
Light-to-MIDI (A-179 + A-192)
Sequencer-to-MIDI (A-155 + A-192)
Envelope-to-MIDI (A-119 + A-192)
Random-to-MIDI (A-118 + A-192)
MIDI
interface for Vocoder (A-129-1 -> A-192 / A-191 -> A-129-2)
Breite/Width: 12TE/12HP, Strombedarf/Current: 80 mA
Preis/Price:
Euro 125.00 (i.e. about US$ 125.00, the price in US$ depends upon the exchange
rate between Euro and US$ at the payment day)
If
you are in the UK or Ireland, ask Alan, the doepfer dealer in Bristol, to provide
you the right power supply. (a weird +/- 12 volts)
There are obviously MIDI to CV artefacts to do te inverse operation. We could control old synthesisers.
Module A-198 is planned as a Trautonium resp. Ribbon controller. The
controlling element of the A-198 is a linear position sensor (length about 50
cm) that has available a pressure sensor too.
The picture above shows the prototype of the Frankfurt music
fair
Touching the sensor with a finger generates a control voltage CV1 that is
proportional to the position of the finger. The scale (i.e. the relation between
position difference and voltage difference) is adjustable with a potentiometer
at the front panel. Additionally a gate signal is generated whenever a finger
touches the sensor (e.g. for triggering an envelope generator).
A pressure
sensor located below the position sensor generates a second control voltage CV2
that increases with higher pressure of the finger. Even for CV2 the scale is
adjustable. A second gate signal is triggered as soon as the pressure exceeds a
certain value (probably adjustable at the front panel for the final
version).
The connection between the module and the sensor combination is
made by a 5 pin cable (same connector type as MIDI or SYNC). The sensor will be
located in a separate metal frame (length about 55 cm, width about
5cm).
Typical applications:
Trautonium manual, the string is replaced by the position sensor that is much easier to use and cheaper than the string. In combination with the Subharmonic Oscillator A-113, the Trautonium Filter A-104 and some auxiliary modules a complete Trautonium replica may be realized. In combination with the Quantizer A-156 exact semitone intervals are possible.
Ribbon Controller for any A-100 parameter (e.g. filter frequency, loudness, speed and so on)
Remark: This information is not an obligatory product announcement. We do
not guarantee that this device will go into production. At the Frankfurt music
fair in March 2002 we will show the prototype of the A-198. The decision on the
production will depend upon the customers inquiry.
Current state (as of April
2002): Because of the positive reactions during the Frankfurt music fair and the
many inquiries we will produce the manual in every case. We hope that the first
devices will be available in June/July 2002. The price will be about 150.00 ...
200.00 US$ (manual and controller module), a MIDI version is scheduled for fall
2002
Breite/Width: ca. 8 TE/about 8 HP, Strombedarf/Current: 50 mA
Preis/Price: about Euro 150.00 ... 200.00 (i.e. about US$ 150.00 ... 200.00,
the price in US$ depends upon the exchange rate between Euro and US$ at the
payment day)
LIGHT TO CV
Module for converting different illumination intensities
into corresponding analog voltage and a gate signal derived from the analog
voltage. A sensor converts the illumination of the internal light sensor (light
sensitive resistor / LDR) into a corresponding analog control voltage. The
internal sensor is located at the front panel (int. LDR) of the module but a
remote sensor may be connected via cable to the module (jack: ext. LDR). Thus
the module A-179 is similar to the Theremin module A-178 but uses the
illumination intensity instead of the distance between hand and antenna for
generating the analog voltage.
Inputs: ext. sensor
Outputs: normal CV,
inverse CV, Gate
Controls: Offset voltage (for adjusting the CV to 0V for the
desired illumination), Gate threshold
Displays: 2 LEDs for CV
(positive/negative), 2 LEDs for inverse CV (positive/negative), 1 LED for
Gate
Applications:
controlling any voltage controlled parameter of the A-100, e.g. pitch or
pulswidth (VCO A-110), loudness (VCA A-130/131/132), panorama (A-134), filter
frequency or resonance (A-120/121/122/123), phasing (A-125), frequency shift
(A-126), resonance peaks (A-127), envelope parameters (A-141/142), tempo
(A-147), passive control by covering/shading the sensor via hand or body, active
control by using pocket lamp/flashlight/laser.
triggering of A-100
activities via gate with adjustable threshold, e.g. starting an envelope
(A-140/141/142), Start/Stop of a sequence (A-155), any switching function
(A-150/151)
For detailed information you may look at the A-179 user's guide
(English version).
Breite/Width: 8TE/8HP, Strombedarf/Current: 50 mA
Preis/Price: Euro 50.00 (i.e. about US$ 50.00, the price in US$ depends upon
the exchange rate between Euro and US$ at the payment day)
Theremin module for generating a variable control voltage by
approaching/removing hand to/from an antenna. Additionally the module is
equipped with a Gate output with adjustable threshold level. Probably the module
will also be available in a version with a separate case so that the antenna can
be placed outside the A-100. Controls/Inputs/Outputs: antenna input, offset
(knob for zero adjust), 2 x CV out, 2 x LED (for CV control positive/negative
and zero offset adjust)
To simulate the original Theremin two A-178, a VCO
(e.g. A-110) and a linear VCA (e.g. A-130 or A-132) are required. But of course
the A-178 can be used to control other functions in the A-100 (e.g. filter
frequency, modulation depth and/or speed, tempo, attack/decay time and so
on).
A similiar module using the illumination intensity instead of the
distance between hand and antenna is the Light-to-CV Converter A-179.
For
detailed information you may look at the A-178 user's guide (English
version).
Applications:
controlling any voltage controlled parameter of the A-100, e.g. pitch or
pulswidth (VCO A-110), loudness (VCA A-130/131/132), panorama (A-134), filter
frequency or resonance (A-120/121/122/123), phasing (A-125), frequency shift
(A-126), resonance peaks (A-127), envelope parameters (A-141/142), tempo
(A-147), passive control by covering/shading the sensor via hand or body, active
control by using pocket lamp/flashlight/laser.
triggering of A-100
activities via gate with adjustable threshold, e.g. starting an envelope
(A-140/141/142), Start/Stop of a sequence (A-155), any switching function
(A-150/151)
Breite/Width: 8TE / 8HP, Strombedarf/Current: 50
mA
Preis/Price: Euro 75.00 (i.e. about US$ 75.00, the price in US$
depends upon the exchange rate between Euro and US$ at the payment day)
Der
Preis beinhaltet die steckbare Teleskop-Antenne / Price includes the telescope
antenna.
theremax
by paia
THE MIDIBRAIN by paia.com
This 8031 based CV to MIDI converter is available with your choice of firmware for either a MIDI Fader or MIDI Drum Brain. MIDI-In and Out connectors provide easy integration into a data stream and allows multiple Brain cards to be daisy-chained in applications requiring more than eight inputs. Compact 4" X 6" form factor easily mounts in the enclosure of your choice or behind a 2W FracRak panel. Requires +5V @ 150 mA. power and there are provisions on the board for filter capacitors and voltage regulator for operation from higher voltage supplies.
The MIDI Fader firmware converts eight 0-5V inputs into MIDI Control Change, Pitch Wheel and Channel Pressure messages. A DIP Switch selects Basic Channel and contiguous groups of Continuous Controllers. Input sources can be simply potentiometer voltage dividers or CVs from Keyboards or alternative controllers. No external processing is usually required, as shown in the example. This is the 9201fk in the price list below.
The Drum Brain
firmware converts trigger pulses from eight analog percussion sensors into MIDI
Note On/Off and Velocity data. With appropriate interface circuitry sensors can
be either Piezo Disks, Force Sensing Resistors or Electret Mics . The DIP switch
selects Basic Channel,1 of 8 sensor-to-MIDI-Note# maps (one user programmable)
and exponential or linear Velocity response. This is the 9201dk in the
list.
The 9301k Sensor Board
kit is useful because it has processing electronics for external sensors and
includes wall mount power supply, regulator, filter caps and so on to provide
power for itself and Brain board both. Ten piezo disks are supplied and can be
mounted on the board for a midi finger drum or extended on cable to serve as
remote sensors. Two pairs of sensors are assigned to single input channels allow
for rolls using index and middle fingers. At 5-1/2" X 6-3/4" it is somewhat
larger than the MIDI Brain board, but the two are designed to be sandwiched with
spacers as shown.
If you want to
take finger drumming to it's logical conclusion, or even a little beyond, there
are two case styles available. The 9300c ThumDrum Case kit shown to the left
encloses the 9201dk Drum Brain and 9301k Sensor Board kit. Rubber percussion
pads to cover the piezo disks and provide a resilient percussion surface are
included with the case.
The FingerDrum is
electronically identical to the ThumDrum but arranges the pads for two hand
operation. The FingerDrum electronics board is not very useful without the case,
so case and electronics are included in the 9150k FingerDrum kit. The FingerDrum
alone is a useful controller for triggering Drum Boxes and Brains from other
manufacturers, for MIDI output the 9201dk must be purchased
separately.
Cat #
Description price US
Shipping
---------------------------------------------------------------
9201
MIDI Brain kit includes circuit board,
MIDI Jacks and electronic parts
exclusive of power supply ............. us$87.75 (6.00)
Specify: 9201dk
Drum Brain PROM or
9201fk MIDI Fader PROM.
9301k
ThumDrum Sensor Board kit includes
circuit board, electronic parts
and
connectors, piezo disks, 120VAC wall
mount power supply
.................... us$54.25 (6.00)
9300c
ThumDrum Case kit including wood end caps,
foam percussion pads and all metal
and
hardware .............................. us$28.50 (7.00)
9150k
FingerDrum kit includes sensor board and
all electronic parts and connectors
as
well as case and power supply. Does not
include MIDI Brain
.................... us$89.95 (7.00)
2) Programming PIC microcontrollers.
Pic microcontrollers are mainly used to automate machinery and processes in factories.
Example 1) Parallax. (basic)
http://www.parallaxinc.com/html_files/getting_started/gettingstarted_stamps1.htm
Example 2) The FED 40 pin PIC Development Board is shown below. (C)
The Forest Electronic Developments C Compiler Version 8.0
NOW £60.00, only £45.00 if ordered with WIZASM or a programmer
NEW Professional Version
Application Designer Front End - WIZ-C
With External Device Simulation, floating point and PIC18CXXX support
Supports the FED In Circuit Debugger
Download the FED PICMicro® MCU C manual and our full introductory manual
"Learn to program in C with FED"
THE FED C Compiler is intended for all serious programmers of the PICmicro® MCU who would like the convenience of a high level language together with the speed of assembler. With our C Compiler you no longer have to worry about ROM and RAM paging, you can call to a depth limited only by RAM not by the 8 level call stack, use 8, 16 or 32 bit arithmetic types for full precision, and use any of our standard library routines for general purpose data handling and interfacing.
The FED PICmicro® MCU C compiler will handle any of the current 14 bit PICmicro® MCU's plus the PIC18CXXX 16 bit core devices and future devices may be added by changes to initialisation files. All devices are handled by standard C header files.
The standard version on CD-ROM is £60.00 (or $80.00 to our US customers). WIZ-C costs £70.00 with application designer manuals. To include a printed version of the C Compiler manuals add £60.00 (or $20.00).
The professional version on CD-ROM is £90.00. WIZ- C professional costs £100.00.
CUT Price with our other products Price is only £45.00 if ordered with WIZASM, or one of our Programmers or with the Development Board.
Features :
Designed to ANSI C Standards
Integrated Compiler Environment
Debugging Support within the environment
Supports full range of 14 bit
and PIC18CXX 16 bit PICmicro® MCU's
Efficient code production
Floating
point support
Wide range of library functions
Forest Electronic
Developments
Simulators for PICmicro® MCU and AVR
Supports the new FED In Circuit Debugger
Now with External Device Simulation
FED's simulators allows you to develop your projects in one Windows program. PICmicro® MCU version supports PIC16C5X, PIC12C5XX, PIC12C67X, PIC16CXX, PIC16FXX, PIC16F87X including PIC16F877, and PIC18CXXX
Full
editor with syntax highlighting in color. Follow your code as it steps through
the editor window, view help file information directly from the code
Set
breakpoint on line, jump to label, evaluate memory variables all by single click
Simulator allows addressed, conditional and timed breakpoints
Simulator
runs up to 50 times faster than DOS based simulators, 10 times faster than other
Windows based simulators !
Trace Analyser allows any register or port value
to be examined in analogue (graphical), waveform, or numeric values, check your
program directly against your predicted waveforms.
Debugger allows variables
to be examined in byte, word or long form, octal, decimal, hex and floating
form, also dump memory areas
Profiler examines and times called routines -
use it to optimise out bottle necks and check timing loops
Track errors and
jump straight to error lines
Input stimuli include clocks, direct values and
asynchronous serial data.
Allows full use of Windows ’95 and Windows NT 4.0
facilities - controls and long filenames.
Includes full terminal emulator
program and support for in-circuit debugging on all devices
Screenshots of
PICmicro® MCU Simulator and Wave Analyser
Cost £20.00 Please specify Windows
3.1, or Windows ’95 (32 bit) versions of PICmicro® MCU Simulator. AVRDE is only
available for Windows ’95.
In Circuit Debugging System (ICD) for the PIC16F87X series by Forest Electronic Developments
What is In-Circuit Debugging (ICD) ?
In Circuit Debugging is a technique where a monitor program runs on the PICmicro® MCU in the application circuit. The ICD board connects to the MCU and to the PC. From any of our applications it is then possible to set breakpoints on theMCU, run code, single step, examine registers on the real device and change their values. The ICD makes debugging real time applications faster, easier and more accurate than simulation tools available for the MCU. The FED in circuit debugger has the following features: ·
Supports all PIC16F87X series PIC's (examples use PIC16F877).
Allows
real hardware to be examined and programs to be debugged in the application and
to be run in real time.
Low cost board which has only 4 connections to the
application circuit (2 Power, data and MCLR).
Powered from the application
circuit (3.3V to 5V)
The FED ICD requires only one data I/O pin on the
PICmicro® MCU which can be chosen from any of ports B, C or D.
Can program
and re-program applications in circuit
Up to 3 breakpoints
Run, single
step and step over, run to cursor line, set PC to any value in the program
Trace execution in the original C or Assembler source files
Animate
operation to trace variables at breakpoints or watch the program executing
Auto Run application if ICD not connected
View and change values of MCU
special function and general purpose registers, W and the ports.
Uses a
standard (3 wire) serial interface to a PC
More detail on the use of the ICD
and a comparison with other systems
Appendix.
DIY! - Sensory Devices
Some of the
most interesting technical innovations in this field can be seen in the sensory
devices used to gather information from the real world. The purpose of these
devices is to measure the actions of a person, often a performer, and to make
the data available to a device that can respond intelligently to what is
happening.
In terms of commercially available devices, we have attempted to list the best known and most readily available sensors here. For an exhaustive list, see Axel Mulder's excellent Human Movement Tracking Technology paper and its addendum.
Making Your Own Sensors
There are two
reasons that you may need to create your own sensory devices. The first strike
against commercial sensors is probably their expense. We are artists after all,
and that means we're usually short on cash. The second reason is that
off-the-shelf objects may not measure the specific actions that you are looking
for, or may not measure them in the way that you need. This section is designed
to help you find the information you need to create simple and relatively
inexpensive interactive sensory systems.
If you are a beginner, we strongly encourage you to start at Dan O'Sullivan's incredible Physical Computing pages. This "hands on guide for artists" goes into great detail, from choosing sensors to soldering to interfacing them to a microcontroller.
Next, we would like to list a few very simple ideas for beating off-the-shelf components into submission for your own purposes.
Drum Controllers and Drum Machines
Many drum
controllers (Roland Pad-80) and some drum machines (Alesis HR-16) have inputs
for external triggers. These inputs can be connected to piezo sensors, which
respond to vibration or impact. You can purchase these sensors at Radio Shack
very inexpensively, and then hook these up to the inputs on the drum controller
or drum machine. Once you have done so, striking the piezo should generate midi
note on / off messages. Because they are small and thin, the sensors can be
attached to a number of surfaces (walls and floors), embedded in costumes,
etc.
MIDI Fader Boxes
There are
a number of commercially available MIDI Fader Boxes, which usually sport a
number of knobs or sliders. Moving the slider causes some kind of MIDI
information (often a continuous controller message) to be sent out of the box.
It is fairly easy to crack open these boxes, disconnect the existing faders and
replace them with your own. This requires a bit of courage because it is
possible to destroy the object in question if you are unskilled with a soldering
iron, etc. The procedure is outlined below.
There are a number of possible applications, but obvious choices include measuring the angle of joints, how a viewer is touching parts of an installation, etc.
Note that we do not assume any responsibility for damage that occurs when modifying devices in the way described below. If you are at all unsure how to do the following procedure, either don't do it or find a knowledgeable friend to help you!
Disconnect power from the device and open its enclosure.
Look for the
wires that are connected to the sliders or knobs (we'll call them faders from
here on.) There should be three wires connected to each fader.
Make a
diagram of the wires connected to the fader. Better yet, number the contacts
with a permanent marker and then, using a piece of tape, mark each wire with its
matching number.
Unsolder the wires from the fader.
You will need to
find out the resistance value of the fader. If there is a rating printed on the
fader itself, i.e., 100K or 10K or something like that, you may not need to do
the following procedure. If not, you can measure the resistance yourself using a
volt-ohm-meter.
To find out the fader's resistance value, measure the
resistance between all three pairs of contacts. Two pairs will change resistance
when you move the fader. One pair will not. The resistance of the fader between
these two points is the fader's rated resistance. At this moment, the connection
that you are not touching is called the "wiper." Make note of this.
At your
local electronics store or Radio Shack, purchase a potentiometer with the same
rating as you found in the previous steps. Either a rotary or linear version is
OK whatever suits your purpose.
You will want to solder your
potentiometer in place of the fader that you disconnected. On the potentiometer
that you purchase, you can determine the "wiper" in exactly the same way that
you did above. On rotary potentiometers, the wiper is always the connection in
the middle of the group of three.
Attach the wire that used to go to the
wiper on the device's fader to the wiper of your new potentiometer. Then attach
the other two wires to the remaining two connection points it does not
matter which one.
That's it. You should be able to turn on power to your
device, and use your new fader to generate MIDI in the same way in which the old
fader did.
Custom Devices
Many artists have created
their own sensory systems to suit their specific needs. These creations range
from the simplest hybrids of multiple off-the-shelf items to systems that were
created from the ground up. We have listed several of the devices that we know
of here, in the hopes that they may serve as source of ideas and
inspiration.
MidiDancer. MidiDancer, created by Mark Coniglio, allows the movements of a performers body to generate MIDI information. The sensors measures the flexion of several joints (wrists, elbows, hips, and knees) of the body. The resulting movement information, measured is sent via a wireless link to a box that decodes the information and passes on to a computer in the form of MIDI continuous controller information.
BodySynth. Developed by Chris van Raalte, the BodySynth uses EMG (Electro-Myographic, i.e., muscle contraction) sensors to generate MIDI information. The resulting information is sent via a wireless link to a decoder, which then passes the information on to a computer for processing. This unit was commercially available at one time, though I am not sure if it is any longer in production. Please send an email if you have more current information.
Commercial Devices (In
Production)
IceCube. Axel Mulder's IceCube is a input
device that can measure a wide variety of input sources. Sensors available for
the IceCube include: illumination, , pressure (touch), temperature, short range
(up to 7 cm) proximity, rotation and with several others in development.Output
is in the form of MIDI System Exclusive messages. The package also includes MAX
objects designed specifically to take advantage features of the IceCube
system.
Lightning and marimba lumina. Don Buchla's lighting allows the
computer to track the position of two "wands" in space. The wands (actually
small infra-red transmitters) are generally held in the hands of the performer,
and moved about in front of a receiver. Thunder can use the position of the
wands to generate various kinds of MIDI data, including note on/off and
continuous controller information.
SensorLab. Created at STEIM in Amsterdam, the STEIM SensorLab is a small, general purpose, analog to MIDI interface for the prototyping of musical instruments and interactive control systems. This box has 32 channels of analog to digital conversion, 2 ultrasound inputs for measuring distance between sensors, 128 switch inputs and more.
Very Nervous System. David Rokeby's system has received a lot of attention and has been used in several notable installations. VNS is a non-invasive motion tracking system that analyzes input coming from a video camera. It can sense motion in a space and where that motion occurs. Output from the VNS via a SCSI connection, meaning that you connect it to your computer like a SCSI hard disk drive or scanner. Objects are provided that allow access from the MAX programming environment.
Theremin. Almost certainly the first electronic instrument, the Theremin was created in 1919 by its namesake Leon Theremin. The device uses two metal antennae to sense the motion of the hands in space near the device. One antenna controls the volume of the device, while the other controls the pitch. Bog Moog's company Big Briar now makes a Theremin that outputs MIDI information. There is much information to be found on the net, starting with Jason Barile's Thermin Home Page.
Commercial Devices (No Longer In Production)
Because of the small number of creators making use of alternative
controllers, many have come and gone. Still, you may find one of these items
wandering about looking for a home so we felt it was important to mention some
of these devices here.
Airdrums. Created by inventor Pat Downs, the Airdrums were a pair of MIDI batons, about the size of claves, that send messages when moved on their axes in various directions. Each axes was sensitive to motion in six axes, and each axis able to send a pre-programmed series note on events and other MIDI data. (You can find a review in Keyboard Magazine's January 1987 issue)
Gold-Brick Interface. This box converted signals from a Nintendo Power Glove (see below) into MIDI. A fair number of people seemed to be using this system at one time, so you might be able to find one used.
PowerGlove. The Mattel PowerGlove was originally marketed as an interface to Nintendo video game systems. But its ability to track both position of the hand in space (using ultrasonic sensors) and the bending of the fingers led to almost instant hacking by many artists. In its off-the-shelf configuration, the glove required custom hardware to get at the data. Later the Gold-Brick Interface (see above) converted the output into MIDI, which made it much easier to use. One important development was the Chris Hand has written a good summary of the device and its history, and a PowerGlove FAQ has been compiled by J. Eric Townsend.
->
last Source (look for more at): 
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ELECTRONIC PROJECTS FOR
MUSICIANS
by Craig Anderton
Even if
you don't know an ohm from a volt, Craig Anderton's revised and expanded book
shows you how to build 27 accessories that enhance your sound and broaden your
musical horizons. If you're an old hand at musical electronics, you'll really
appreciate that all of the processors, from tube sound fuzz to phase shifter are
compatible and work together without creating noise, signal loss, bandwidth
compression or any of the other problems common to interconnecting effects from
different manufacturers. There's even a complete chapter on how to modify and
combine effects to produce your own custom pedal board. Low cost project kits
available from PAiA help make even your first exposure to electronics a
pleasant, hassle-free experience and thanks to CD bound into the book, you know
just how the device will sound before you even start.
EPFM
Electronic Projects for Musicians Book.............$27.95 (4.00)
... we are
presently shipping book and kits from stock..
EPFM the
kits
These kits include circuit board and all components. Instructions for
the assembly of each kit are part of the book "Electronic Projects for
Musicians" and are not duplicated with the kit. To allow maximum flexibility in
their application, no cases or enclosures are included, but the new PAiA Fracrak
card cage is an economical alternative to the Vero (tm) cases shown in the book.
Circuit boards are available alone at the prices listed under "pc only". Kit
w/pc prices are for all parts and includes the circuit board.
Demo
Samples by Criag Anderton from the Electronic Projects for Musicians
CD.
EPFM kits Cat # Name pc only kit w/pc
CA-1
Preamp (less XLR & VU) $9.95 $29.95
CA-2 Metronome $7.95 $19.95
CA-3
Passive Tone Control $6.95 $19.25
CA-4 Headphone Amp $7.95 $19.95
CA-5
Mini-Amp $7.95 $36.95
CA-6 Ultra-Fuzz $7.95 $19.95
CA-7 Sample Bass-Fuzz
$7.95 $21.95
CA-8 Compressor/Limiter $7.95 $29.95
CA-9 Sample Ring
Modulator $8.95 $34.50
CA-10 Dual Filter Voicing Unit $8.95 $29.95
CA-13
Bipolar AC Adapter $9.95 $34.95
CA-14 Treble Booster $7.95 $12.95
CA-15
Electronic Footswitch $8.95 $19.95
CA-17 Super Tone Control $8.95
$32.25
CA-18 8 In 1 Out Mixer (less XLR.) $9.95 $49.50
CA-20 Practice Play
Along $8.95 $24.95
CA-21 Sample Phase Shifter $12.95 $69.95
CA-24 Sample
Tube Sound Fuzz $7.95 $22.95
CA-25 Sample* Envelope Follower $8.95
$26.95
CA-26 Spluffer (less optional parts) $8.95 $14.95
CA-27 Noise Gate
$12.95 $32.95
*In this sample the Envelope Follower is controlling the CA-21 phase shifter
Postage and Handling: please add $2.00 for each circuit board ordered
alone and $4.00 for each kit.
BASIC ELECTRONIC CIRCUITS EXPLAINED
In this section we will discuss what a circuit is. I
won't belabor the principles of the atom -- let a physics text handle that
(boring) task. Instead let's talk about the facts you will need to know to get
started in electronics.
Circuit
A circuit is a path for electrons to flow through. The path
is from a power sources negative terminal, through the various components and on
to the positive terminal.
Think of it as a circle. The paths may split off here and there but they always form a line from the negative to positive.
NOTE: Negatively charged electrons in a conductor are attracted to the positive side of the power source.
--------------------------------------------------------------------------------
Conductor
A conductor is a material (usually a metal such as copper)
that allows electrical current to pass easily through. The current is made up of
electrons. This is opposed to an insulator which prevents the flow of
electricity through it. 
--------------------------------------------------------------------------------
Simple Circuit
If we break a circuit down to it's elementary blocks
we get:
1) A Power Source -- eg: battery
2) A Path -- eg: a wire
3)
A Load -- eg: a lamp
4) A Control -- eg: switch (Optional)
5) An
indicator -- eg: Meter (Optional) 
--------------------------------------------------------------------------------
Series Circuit
A series circuit is one with all the loads in a row.
Like links in a chain. There is only ONE path for the electricity to flow. If
this circuit was a string of light bulbs, and one blew out, the remaining bulbs
would turn off. There are specific properties to this circuit that will be
described in another section.
NOTE: The squiggly lines in the diagram are
the symbol for Resistors. The parallel lines are the symbol for a
battery.
--------------------------------------------------------------------------------
Parallel
Circuit
A parallel circuit is one that has two or more paths for the
electricity to flow. In other words, the loads are parallel to each other. If
the loads in this circuit were light bulbs and one blew out there is still
current flowing to the others as they are still in a direct path from the
negative to positive terminals of the battery. There are specific properties to
a parallel circuit that will be described in another section.
--------------------------------------------------------------------------------
Combination
Circuit
A combination circuit is one that has a "combination" of series and
parallel paths for the electricity to flow. Its properties are a synthesis of
the two. In this example, the parallel section of the circuit is like a
sub-circuit and actually is part of an over-all series circuit.
Be
sure to check out my book -- Howard W. Sams Internet Guide to the Electronics
Industry*
Information
Submit new URLS Comments
* Spam or not, I have
to make a living :-)
Entire contents of this site are copyrighted --
Copyright 1997 * InfiNet-FX and John Adams
Contact the Webmaster Last
Updated: Sept 15, 1997
VOLTAGE, CURRENT & RESISTANCE EXPLAINED
In electronics we are dealing with voltage, current and resistance in
circuits. In the next section we'll learn that by using Ohm's Law we can
determine one value by knowing the other two (For example: Figure out Current by
using Voltage and Resistance values). So it is important to firmly grasp the
basics of Voltage/Current/Resistance first.
We will describe these electrical terms using an analogy that closely resembles electronics — HYDRAULICS.
--------------------------------------------------------------------------------
Voltage
Voltage is the electrical force, or "pressure", that causes
current to flow in a circuit. It is measured in VOLTS (V or E). Take a look at
the diagram. Voltage would be the force that is pushing the water (electrons)
forward. 
--------------------------------------------------------------------------------
Current
Current is the movement of electrical charge - the flow of electrons through
the electronic circuit. Current is measured in AMPERES (AMPS, A or I). Current
would be the flow of water moving through the tube (wire). 
--------------------------------------------------------------------------------
Resistance
Resistance is anything that causes an opposition to the flow of electricity
in a circuit. It is used to control the amount of voltage and/or amperage in a
circuit. Everything in the circuit causes a resistance (even wire). It is
measured in OHMS (W).
diagram for this section might be misleading...
OHM’S LAW EXPLAINED
--------------------------------------------------------------------------------
“The
amount of current flowing in a circuit made up of pure resistances is directly
proportional to the electromotive forces impressed on the circuit and inversely
proportional to the total resistance of the circuit.”
Don’t let that quote
scare you. It is not as scholarly as it sounds.
Before going further make sure you understand:
• What composes a
circuit.
• What voltage, current and resistance are.
--------------------------------------------------------------------------------
In simpler terms, Ohm’s Law means:
1) A steady increase in
voltage, in a circuit with constant resistance, produces a constant linear rise
in current.
2) A steady increase
in resistance, in a circuit with constant voltage, produces a progressively (not
a straight-line if graphed) weaker current.
--------------------------------------------------------------------------------
Ohm’s
Law is a set of formulas used in electronics to calculate an unknown amount of
current, voltage or reistance. It was named after the German physicist Georg
Simon Ohm. Born 1787. Died 1854.
Knowledge of this Law is often
under-estimated by beginners. I have talked to people that can design complex
circuitry and microprocessor systems that have said, “Ohm’s Law? What’s that?”.
Unless you know this basic fundemental building block of electronics, you will never have a strong foundation to hold up the electronics towers you will be constructing in the future. Learn Ohm’s Law. Learn it inside and out!
--------------------------------------------------------------------------------
TECHNICAL DEFINITION ALERT!
Ohm's Law is a formulation of the
relationship of voltage, current, and resistance, expressed as:
Where:
V is
the Voltage measured in volts
I is the Current measured in amperes
R is
the resistance measured in Ohms
Therefore:
Volts = Amps times Resistance
--------------------------------------------------------------------------------
Ohms
Law is used to calculate a missing value in a circuit. 
--------------------------------------------------------------------------------
In this simple circuit there is a current of 12 amps (12A) and a
resistive load of 1 Ohm (1W). Using the first formula from above we determine
the Voltage:
V = 12 x 1 : V = 12 Volts (12V)
If we knew the battery was
suppling 12 volt of pressure (voltage), and there was a resistive load of 1 Ohm
placed in series, the current would be:
I =
12 / 1 : I = 12 Amps (12A)
If we knew the battery was suppling 12V and the
current being generated was 12A, then the Resistance would be:
R = 12/12 : R = 1W
Be sure to check out the Ohm's Calculator to help you determine
circuit values.
Note: Remember a battery is not measured in amperage as is commonly
believed with beginners to electronics. The battery supplies the pressure that
creates the flow (current) in a given circuit. The amperage rating on a battery
is "How long the battery will last for one hour while driving a circuit of that
amperage". It is measured in Amperage-Hours. So a 1000mAh would last for 1 hour
in a one amp circuit. (1000mAh is 1A for one hour)
An easy way to remember
the formulas is by using this diagram. 
To determine a missing
value, cover it with your finger. The horizontal line in the middle means to
divide the two remaining values. The "X" in the bottom section of the circle
means to multiply the remaining values.
• If you are calculating voltage, cover it and you have I X R left (V= I times R).
• If
you are calculating amperage, cover it, and you have V divided by R left
(I=V/R).
• If you are calculating resistance, cover it, and you have V
divide by I left (R=V/I).
Note:
The letter E is sometimes used instead of V for voltage.
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Microcontroller is a computer on a chip that is programmed to perform almost any control, sequencing, monitoring and display function. Because of its relatively low cost, it is a natural choice for design. It performs many of the functions traditionally done by simple logic circuitry, requential control circuits, timers or a small microcomputer.
The 8051 is an 8 bit microcontroller originally developed by Intel in 1980. It is the world's most popular microcontroller core, made by many independent manufacturers. A typical 8051 contains CPU with boolean processor, 5 or 6 interrupts, 2 or 3 16-bit timer/counters, programmable full-duplex serial port, 32 I/O lines, RAM and ROM/EPROM in some models. The 8051 architecture is quite strange and original. One strong point of the 8051 is the way it handles interrupts. Vectoring to fixed 8-byte areas is convenient and efficient. The 8051 instruction set is optimized for the one-bit operations so often desired in real-world, real-time control applications. The 8051 has the widest range of variants of any embedded controller on the market. The smallest device is the Atmel 89c1051, a 20 Pin FLASH variant with 2 timers, UART, 20mA. The most powerful chip is the Infineon Technologies 80C517A, with 32 Bit ALU, 2 UARTS, 2K RAM, PLCC84 package, 8 x 16 Bit PWMs, and other features.
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