**Course: ENGN1230 –
Bioinstrumentation Design**

**Designation: **Required for BME, Bioelectrical,
Biomechanical

**Instructor: **Professor J.D. Daniels; for 2013 there were
38 students in the class and the instructor was aided by 6 undergraduate TAs, 3
grad student TAs (each 6 hr/wk) and one machinist (Paul Waltz), half time.

**Course Description:** Instrumentation topics of interest to
biomedical engineers, from sensors to computer data acquisition. Sensors: including strain gauges,
thermocouples, microphones, phototransistors, electrodes for nerve cell
signals. Amplifiers: op amps,
instrumentation amplifiers and particularly isolation amplifiers. Filters. Frequency Analysis: A-D
conversion and the sampling theorem; aliasing; windows for smoothing data;
Statistical analysis: binomial distribution; Poisson distribution and Katz’
confirmation of quantal release at NMJ. The t-test of
samples from populations of unknown stats. Use of an
iconic data flow language LabVIEW for designing “virtual instruments.” Electrical safety and noise reduction; design of ground fault interruptors and defibrilators.
Rotating machinery as motors, generators (tachometers) and
electrical brakes. Automatic control and the role of
sensory feedback; PID controllers; neural networks and fuzzy logic.

Lectures, Laboratory exercises, contract grading.

**Website: **http://www.brown.edu/Departments/Engineering/Courses/En123/index.html**
**

**Prerequisite:** Engineering core, including Electricity and
Magnetism, and Differential Equations.

**Text: **none required; online lectures notes and power
point slides provided.

**Class Schedule: **MWF 10-10:50 lectures, and
self-scheduling of about 8 hours per week in lab; one “guaranteed appearance
hour” per week.

**Topics:
*** Review of basic circuits course:
Resistance, Capacitance, Inductance, Transistors; node admittance matrix method
of solving KCL equations

* Creating and
meeting specifications for a project

* Trade-off between
sensitivity and range in design of sensory systems

* Sensors for
electromagnetic radiation (ultraviolet, visible light, and infrared)

* Amplifiers: op amp
circuits, input impedance, GBWP, CMRR

* LabVIEW DAQ
software: front panel and block diagram; NI DAQmx and
6024E PCI card specs

* Electrical safety,
ground, shielding and noise: dangers of electrical current; GFI design;
defibrillator design; radiation dangers

* Design of LP and
HP VCVS filters; digital filters in LabVIEW; combining LP and HP for bandpass
and band-reject filters

* Temperature
sensors: platinum standard; thermistors (self-heating and in a Wheatstone
bridge), thermocouples; IR heat sensors; liquid crystals

* Strain gauges;
converting strain gauge amplifier output back to Young’s modulus of underlying
material

* Analog-to-digital
conversion; successive approximation, flash and dual slope converters

* Sampling Theorem,
FFT, minimum resolvable frequency, aliasing

* Hypothesis
testing: statistical analysis of data; binomial distribution; ethics of
handling false positives in biomedical testing

* Poisson
distribution: application to quantal nature of synaptic transmission

* Electrodes for
recording from electrical signals from tissue: EMG, EKG

* Electrochemistry:
chemical reactions at the metal-aqueous interface

* Nernst equation;
cable equation for signal propagation in dendrites and axons

* Hill’s equation
for Tension-Velocity curves of active muscle

* Negative Feedback
and Automatic Control: PID control; stability

* Rotating
machinery: motors, generators and electrical braking; generators as tachometers

* Motor torque-speed
curve compared to muscle

* Wireless
telemetry: design of 900MHz transmitters and receivers for robot control

**Design projects: (**not all project**s required **to pass the
course**)**

* Window discriminator designed with LabVIEW

* Phototransistors designed into detector of orientation w.r.t.
distant light source

* Design of system for sensing and reacting to contact with a wall, for
wheelchair safety use

* Design with thermistors for Wheatstone bridge system measuring heat gun
output or stirred cold water temperature unknowns

* Design and build a strain gauge system for measuring bending moment of a
fiberglass crutch leg

* Design microdrive advance system for probing the
sensitivity of *blaberus* leg spines to mechanical deflection

* Design a system of
two potentiometers to test the hypothesis that in-phase bimanual knob rotation
can be done at a higher frequency that alt-phase rotation

* Design a method,
using a stepping motor, for automatic measurement of frog gastrocnemius muscle
active length-tension curve (bell-shaped)

* Using small fan as
a tachometer, design method to keep air flow constant by controlling an auxiliary
fan in series with an “unstable” air flow source

* Design a system
using a stationary tandem bike to demonstrate Hill’s hypothesis that muscles
doing “negative” work are stronger than “positive” muscle fibers

* Design on paper a
combination of VCVS LP or HP subfilters that meet
specs for a bandpass or band-reject filter

**Writing assignments: **ENGN1230 is an official WRIT course at

**ENGN1230 addresses
ABET outcomes ** (a), (b), (c), (d), (e), (f),** **(g), (h),** **(j), (k)** **

**Course Goals:** On completion of ENGN1230, each student shall

1. Be able to interpret and formulate design specifications for
instrumentation systems that meet accuracy and sampling speed requirements. Be
familiar with computer-aided design software such as LABVIEW.

2. Understand the principles of operation of sensors including thermocouples, strain gauges (including Wheatstone Bridge circuits) and chemical electrodes.

3. Understand principles of analog and digital signal and data processing, including amplifiers, filters and A-D conversion techniques. Understand sources and measures of error in instrumentation systems, including noise and aliasing; common-mode rejection ratio of differential amplifiers; the sampling theorem and its application.

4. Be able to use appropriate statistical techniques to measure the significance of results obtained from instrumentation systems.

5. Be familiar with safety issues
concerning design of instrumentation, including the effects of electric AC
current passing through tissue.

Understand ground fault interruption and defibrillation.

**Course Improvements (2008-2013)**:

1. Add “guaranteed weekly appearance time” to the duties of each student team,
to insure consist instructor contact on a one-on-one basis.

2. Include more
supported lab experience: we have added labs on (a) quadrature sensing of
rotation; (b) CO2 and O2 sensing of exhaled breath; (c) video microscopy for
watching a microdrive probe move a *blaberus *spine
(d) wireless telemetry using XBee transmitter-receiver pairs (e) adding a lab
that uses accelerometers and gyros to sense orientation of objects held by
subjects in a “Necker Cube” lab. These new labs help cover lecture topics more
thoroughly.

3. Remove “Lab Report” requirement so students have time to perform more hands-on lab exercises; replace lab reports with specific writing assignments the instructor critiques more thoroughly, with more focus on the writing itself, instead of its technical content.

4. Involve on a 3-hour-per-day basis Senior Technical Assistant Paul Waltz in the course, as a person who can repair equipment expeditiously, and design new setups (e.g. the frog muscle stretcher, for Lab LT), freeing the instructor for more direct contact with students in the lab.

5. Improve the Basic Circuits Tutorial section of the course website; better to replace information from a circuits course not required for students in some tracks of the BME concentration.

6. Further refine the grading contract so as to limit the maximum number of A’s in the course to 55% of the enrolled students.

**Professional Component: **75% Design, 25% Engineering
Science