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Nov 2, 2013 (3 years and 9 months ago)

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Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012








Description:

This device serves as an ECG simulator.

It allows the user to
test the six standard ECG machine leads one at a time by
attaching the ECG electrodes to the output jacks on the device
in different combinations.

It is compatible with standard ECG
machines with banana
-
plug

and alligator clip

leads.

It outputs
three types of waveforms at 2 frequencies: a Normal Sinus
Rhythm (NSR), a Pre
-
Ventricular Contraction (PVC) and a sine
wave at 60 beats per minute (bpm) and 100 bpm. The device is
powered by a pair of AA batteries.



Contents:



Box





Cardboard

sheet

Box template




PICAXE
-
08
M2

Proto Board Kit


Proto board PCB

10 k resistor (brown black orange gold)

22k resistor (red red orange gold)

100nF polyester capacitor

3 pin header and jumper link

Stereo download socket

Battery clip

8 pin IC socket



PICAXE
-
08 Microcontroller





Circuit Components



3M resistor (orange black yellow gold)

1k resistor x 3 (brown black brown gold)

1 red circular rocker switch

1 green LED (10mm)

1 round yellow push button

1 round blue push button

10
banana jack
s (5/16”)

10
nuts (5/16”)

2

screw for 3V battery pack (1/8’’)

2

nut for 3V battery pack (1/8”)

4 staples for PICAXE
-
08M2 Proto Board

1 battery holder (3V)



Tools





Sharp, pointy instrument (e.g. tweezers)

Scissors

Soldering Iron

Solder

Wires

Tape

Pen/Marker

ECG

Simulator




Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012


Assembly/Repair Instructions:


PICAXE
-
08 Proto Board Kit

1.

Solder the components as shown in the image.

Be careful
with the following:

a.

The battery clip should be threaded through the
board prior to be soldered.

b.

The 8
-
pin IC socket

has a dent on one side, which
should be pointing in the same direction as the
stereo download socket.

2.

Insert the PICAXE
-
08M2 micro
-
controller after everything
else is in place.



Box

1.

Tape the

4

template

sheets included in the device kit

together. The end result should look like:

















2.

Cut out the template and tape it to the cardboard sheet. Trace the template design onto the cardboard and cut

the

cardboard using
scissors.

3.

Punch out the circles on the template using a screwdriver or other sharp object. Also cut out the black filled
rectangle

and lines within the dotted circles.











4.

Fold along the remaining solid lines.

5.

Assemble the box according to the folds.



Cut here

Top

Bottom

Battery

Compartment




Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012

Circuit

1.

The PICAXE proto
-
board has labeled nodes
(near the
microcontroller
)

that are electrically co
nnected to the
microcontroller

pins.
N
odes connected by lines on the proto
-
board are electrically connected.

2.

Refer to the diagram below t
o create the
ECG Simulator Circuit

a.

Use

the 3M ohm
(orange black yellow gold)

resistor to

connect pin 0 with an empty node.

b.

Solder a long wire which will
connect

Lead 1 to this node.

c.

Connect t
his node to ground (G) using 1k
ohm (brown black red gold) and 100 ohm (brown black
brown gold) resistors in series.

d.

Solder one long wire to V+ that will lead to a push button.

e.

Solder another long wire to pin 1 that will lead to the same push button.

f.

Use a 1k ohm (brown black red gold
) resistor to connect pin 1 to ground.

g.

Solder the two long wires to the blue push button on the box cover.

h.

Solder one long wire to V+ that will lead to a push button.

i.

Solder another long wire to pin 3 that will lead to the same push button.

j.

Use a 1k ohm

(brown black red gold) resistor to connect pin 3 to ground.

k.

Solder the two long wires to the yellow push button on the box cover.

l.

Solder one long wire to V+ and one long wire to pin 4
; both

will lead to the green LED.

































Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012

Banana
jack
s

1.

Take the 10 banana
jacks
.
Remove all plastic rings.

2.

Take the sharp, pointy instrument (hereby referred to as “tweezers”, though other instruments may work as
well) and make 10
holes
E1 through E10
, each

approximately 5/16 inch in diameter.

3.

Insert
banana jack
s through the
10 holes.

4.

Using a length of solder, connect
E2 through E10
.

5.

Take two

l
ong piece
s

of wire and strip off the two ends.

a.

Take one wire and w
rap one end around the

banana jack

at E
1
.

b.

Take the other
wi
re and do the same for the
banana
jack

at E2
.

6.

Take
10
hex
nuts

and secure the banana jacks
, making sure that the wires are securely pressed against the
box
.
























E2


E6


E7

E8


E9


E10


E5


E4

E3

O1

P2

P1













E1



L1

L1




Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012

Please refer to the diagrams in the appendix to complete the directions below.

Push buttons

1.

Take the tweezers and make 5/16 inch holes at P1 and P2.

2.

Remove nuts from push buttons.
Insert push buttons through the holes and secure with nuts.

3.

Take four long pieces of wire and strip off the ends.

a.

Take each wire and connect
it to a push button lead.

LED

1.

Insert the two LED leads through L1 and L2.


Power switch

1.

Take the tweezers and a pair of scissors, and make a ~1.75 cm hole at O1.

2.

Remove the nut from the power switch. Insert the switch through the holes and secure with the nut. Make
sure the “I” symbol is above the “O” symbol.

3.

Take two long pieces of wire a
nd strip off the ends.

a.

Take each wire and connect

it to a power switch lead.

B
attery

1.

Take the 1/8 inch screw and push it through the hole at the center

and right

of the 3V battery pack, with the
head of the screw facing inward.

2.

Take the tweezers and make 1/8 inch holes at
B1
-
B4
.

3.

Push the screw
s through B1 and B2
, with the battery terminals
facing the bottom of the box
.


Final assembly

1.

Solder wires from the circuit board t
o the box
.

2.

Snap the battery lead cap onto the battery leads.

3.

Closing the box, push the screws at B1 and B2 through B3 and B4, respectively, and secure using hex nuts.

4.

(Optional) If necessary, secure the circuit board to the bottom of the box using four staples throu
gh holes
C1
-
C8.






























Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012



Instructions for Use:















1.

Use the

red, circular
on
-
off switch to
power the device
on and off.

2.

When
switched on, the device

outputs a
normal sinus rhythm (NSR)

at 60
beats/minute (bpm)
.

3.

Press

the waveform button
to:

a.

1
st
push
:
change the output to
a premature ventricular contraction (PVC) arrhythmia

b.

2
nd
push
: change the output to a 1 mV
sine wave

c.

3
rd
push
: change the output to a flat signal that outputs a square wave each the frequency button is
pressed

d.

4
th
push
: set the device to its original stage,
i.e. Step 3 when the device is first switched on.

4.

Press t
he frequency button
to cycle

between 60 bpm and 100 bpm

for the NSR, PVC, and sine wave.

5.

Press the frequency button to output a square wave when the waveform is flat.

6.

When the device is on, the green LED flashes at the frequency of the signal.


Testing each lead on the ECG machine
:

To read each lead of the ECG simulator, connect the electrodes of the ECG machine to the ECG simulator jacks in the
following configurations.
Note that each lead
will

display the same waveforms.


Lead I: Connect th
e Left Arm (LA) electrode to E1

(the devic
e’s driving jack)
,

and

the Right Arm (RA) and

all of the
other electrodes to
E2 through E10

in any combination.

Lead II: Connect th
e Left Leg (LL) electrode to E1
,

and the Right Arm (RA) and all of the other electrodes to
E2
through E10

in any combination.

Lead III: Connect th
e Left Leg (LL) electrode to E1
,

and the Left Arm (LA) and all of the other electrodes to
E2
through E10

in any combination.

AVL: Connect the

Left Arm (LA) electrode to E1
and all of the other electrodes to
E2 through E10

in any
combination.

AVR: Connect the

Right Arm (RA) electrode to E1

and all of the other electrodes to
E2 through E10

in any
combination.

AVF: Connect th
e Left Leg (LL) electrode to E1

and a
ll of the other electrodes to E2 through E10
in any combination.

V1: Connect
the V1 electrode to E1

and all of the other electrodes to
E2 through E10

in any combination.

V2:

Connect the V2 electrode to E1

and all of the other electrodes to
E2 through E10

in any combination.

V3:

Connect the V3 electrode to E1

and all of
the other electrodes to
E2 through E10

in any combination.

V4:

Connect the V4 electrode to E1

and all of the other electrodes to
E2 through E10

in any combination.

V5:

Connect the V5 electrode to E1

and all of the other electrodes to
E2 through E10

in any
combination.

V6:

Connect the V6 electrode to E1

and all of the other electrodes to
E2 through E10

in any combination.


10 female banana jacks

Waveform push button

Frequency push button

Green LED indicator

On
-
off switch




Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012

Images of ECG simulator outputs:


Normal Sinus Rhythm (NSR)





Preventricular Contraction




Sine Wave:







Square Wave:






Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012







E2

E6

E7

E8

E9

E10

E5

E4

E3

O2

P1

P2

L2

B2





B4










A1

C1
-
C8



E1

B1

B3

L2

Middle

Top

Bottom

Battery Compartment




Duke University

ECG

S
IMULATOR

Design for the Developing World

Version 1
12
/12/2012