Download Sensor Module Microprocessor Module Speaker Module

Purpose
This document is to confirm the requirements of the proximity sensor based Theremin. Intended
audiences are the design team members and practicum project committee. The requirements
specifications are considered conditionally approved.
Design Team
Dennis Gilbert
Walter Hudson
Khoa Nguyen
G. Hewage Thushara
Proximity Sensor Based Theremin
Revision number
Comments
Date
REV 1.0
Initial draft
10/16/2011
REV 1.1
Changes to format and document structure
10/19/2011
Requirements Specification
Table of Contents
Scope of Project…………………………………………………………………………… Page 3
Sensor Module…………………………………………………………………………….. Page 4
Microprocessor Module…………………………………………………………………… Page 5
Speaker Module…………………………………………………………………………… Page 6
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Requirements Specification
Scope of Project:
The proximity sensor based Theremin must employ at least one sensor or input, actuator or
output and a microprocessor. The circuit design must be limited to a two layer PCB with surface
area between 1in2 and 16in2. Any one side of the PCB must not be smaller than 1inch or larger
than 12 inches. Twenty five percent of hardware components must surface mount.
The proximity sensor based Theremin will use two proximity sensors to measure a time varying
input signal relative to the position of the players hands. The signal will be supplied to a
microprocessor which will scale and produce an output signal. An external speaker will be
driven to produce sound. Push buttons will be used to switch between play modes in the
Theremin. Where applicable, passive hardware components will be surfaced mounted on a PCB
based on the above requirements.
The project is divided into three modules the sensor module, microprocessor module and speaker
module. The overall project budget for hardware per Theremin is forty dollars. Theremin
operation is taken to be indoors at room temperature. Design reviews of project will include
schematics, design team documentation and programming code. A block diagram is shown
below
Sensor Module
Microprocessor Module
Speaker Module
5VDC
Push Buttons
Gain / Speaker
Inputs
P
Outputs
Proximity Sensors
Figure 1. Block diagram of the proximity sensor based Theremin
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Requirements Specification
Sensor Module
The proximity sensors must operate from the 5V regulated supply. The sensors must repeatedly
and accurately measure the distance of the player’s hands up to 400 mm. The proximity sensors
must account for background noise levels and unwanted signals. The sensors must have a
reaction time of less than 50ms to avoid delay in playback.
The push buttons must be identifiable to the player. They must provide the microprocessor with
a signal indicating mode of play. As the design stands, the modes of play are direct playback,
record and loop. In direct playback, the Theremin operates in real time. In record and loop, the
Theremin will record a sample of music over a time frame and playback the recorded music
repeatedly. The push button must have a signal indicating mode of play.
Where applicable, all hardware must be surface mount.
Item
Sensor
Engineering Requirement
measure distance up to
400mm
Sensor
account for background noise the output of speaker
module should not play
background noise
Sensor
reaction time <50ms
Pushbutton indication of playback mode
Hardware
Surface mount components
when applicable
Justification
longer range of motion
increases playability and
dynamic range
usability will be reduced
with slow reaction items
upon pressing buttons
player must know that
Theremin is operating in
selected mode
practicum project
requirement
Table 1. Summary of requirements for the sensor module.
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Requirements Specification
Microprocessor Module
The microprocessor must operate from a regulated 5V supply. The processor must be configured
to accept the sensor inputs over the entire operating range of voltages not exceeding 5VDC. The
processor must be configured for the modes of operation and indicate which mode is active by
LED illumination. On board memory must allow for storage of recorded music for a minimum
of 10s. The processor must scale and manipulate sensory input and output a signal to the speaker
module for sound reproduction.
Where applicable, all hardware must be surface mount.
Item
MCU
Engineering Requirement
accept all voltage levels of sensor
inputs
Justification
MCU's resolution must be
over required operating
range
MCU
programmed for modes of operation
key to Theremin design
MCU
LED illumination
must indicate to player
mode of operation,
playback or record /loop
MCU
on board memory
must store recorded music
for playback
Hardware
Surface mount components when
applicable
practicum project
requirement
Table 2. Summary of requirements for the microprocessor.
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Requirements Specification
Speaker Module
Components of the speaker module must operate from a regulated 5V supply. The speaker
module will incorporate an adjustable gain block to produce sound audible to at least a maximum
distance of 5m. The power handling of the gain block must be from 50mW to 1W. A master
volume control must be incorporated into the speaker module. At a minimum, the frequency
response of the gain block must meet the telecommunication standard of 300Hz to 3.4Hz.
The speaker must be 4Ω or 8Ω and external to the Theremin. Mechanically, the speaker must
work with the output waveform of the microprocessor.
Where applicable, all hardware must be surface mount.
Item
gain block
Engineering Requirement
audible sound at a minimum
of 5m
Justification
the Theremin must be
heard
gain block
power handling between
50mW to 1W
a power range is specified
to meet the distance
requirement of at least 5m
gain block
master volume control
gain block
minimum frequency response
300Hz to 3.4Hz
speaker
4Ω or 8Ω speaker
standard speaker resistance
Hardware
Surface mount components
when applicable
practicum project
requirement
Table 3. Summary of requirements for the speaker module.
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