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Builld the
E,cecutive
Thingie
Exaoutiva Ihiugia
Many executives often suffer from a complaint
commonly referred to as "executive stress". If
that fits you, then you need the fast-acting
relief of the Executive Thingie! You simply tilt
the box in any direction to produce four
different and medicinal musical notes.
How many times have you walked
into the boss 's office to find him slowly
sliding under the desk with his eyes
spinning in a counter-clockwise fashion?
Believe it or not, this is a definite
case of "executive stress", the management version of "industrial disease". The question is, what can be
done about it?
We believe that the solution is as
simple as a few ICs and a soldering
iron: get · him (or her) to build the
Executive Thingie. When tilted, this
ingenious device closes one or more
mercury switches, thus triggering a
tone to calm those jangled nerves (or
make them worse)!
Apart from that, the device is completely useless although you may learn
By DARREN YATES
30
SILICON CHIP
a few things while building it. The
unit runs off a 9V battery and uses
easy-to-obtain parts. Indeed, by the
time you have it up and running, your
worries may be over!
Block diagram
Fig.1 shows the block diagram of
the circuit. As can be seen, it uses
four tone generators and these are
made using a single 4093 quad Schmitt trigger NAND gate IC.
Each generator output feeds one of
four voltage-controlled resistive volume controls. These controls are based
on the FETs found inside a couple of
4007 !;lual complementary pair ICs and
are activated by mercury switches
MS1-MS4.
The output from each volume control is then resistively mixed with the
others and fed to an audio output
stage.
In practice, the mercury switches
are split into pairs, with one pair used
to monitor the x-axis and the other
used to monitor the y-axis. When the
device is held perfectly level, all
switches are open and all the voltage
controlled resistors have a very high
resistance. Thus, no tones are fed
through to the loudspeaker.
However, when the device is tilted,
one or more of the mercury switches
will close and their corresponding
voltage controlled resistors will switch
to low resistance. These in turn allow
signals to pass from their corresponding tone generator stages to the amplifier stage.
+gv---i--1--1------.!
MS2
MS1
MS4
MS3
JQIIE.
OSCILLATOR
1
TONE
OSCILLATOR
2
TONE
OSCILLATOR
TONE
OSCILLATOR
3
4
VOLTAGE
CO~T.!ll!!J.!;I)
RESISTOR
DIVIDER 1
VOLTAGE
CONTROLLED
RESISTOR
DiVIDER 2
VOLTAGE
CONTR.OLLED
RESISTOR
DIVIDER 3
R
ij
R
Circuit diagram
OUTPUT
DRIVER
Fig.2 shows the complete circuit
details. It's easy to identify the various circuit sections. ICla, IClb, IClc
& ICld are the tone oscillator stages,
while IC2a, IC2b, IC3a & IC3b are the
voltage controlled resistors. Ql, Q2
and their associated components form
the output driver stage.
Note that the four combined tone
oscillator/voltage controlled resistor
stages are identical. To simplify the
description, we'll just concentrate on
SPEAKER
Fig.I: the Executive Thingie consists of four identical stages which
are activated by mercury switches (MS1-MS4). The various outputs
are then mixed & fed to an audio amplifier stage.
the stage based on ICla and IC2a,
since the other three stages all function in exactly the same manner.
NAND gate ICla is connected as a
square wave oscillator. Its output frequency is set by the lOOkQ trimpot
S1
<>--;]_
100 +
16VWJ
T,
B1
MS1
9V
MS4
~
i
VR1
100k
10k
.022!
322!
.022!
10
2.2
+
25VWr
10
+
390k
390k
.,.
.,.
10k
10k
10k
2.2
2.2
390k
25VWr
.,.
-:-
25VWJ_ 390k
10k
10k
-:-
':'
.,.
,--------•9V
Ic2 1Ic3
100
16VW
E
·1n
B
ELJc
VIEWED FROM
BELOW
Bll
SPEAKER
02
BC327
C
.,.
EXECUTIVE THINGIE
.,.
Fig.2: the four oscillator stages are based on a 4093 quad NANO gate IC (ICl). IC2a, IC2b, IC3a & IC3b
function as the voltage controlled resistor stages while Qt & Q2 form the basis of the audio amplifier.
APRIL 1992
31
The assembled PC board is mounted on the lid of the case using screws, nuts
& shakeproof washers, while the loudspeaker is fixed in position using contact
adhesive. Use a small piece of foam rubber to wedge the battery in position
when the lid is attached.
and the .022µF capacitor on pins 1 &
2. The resulting output signal appears
at pin 3 and is fed via a 10kQ resistor
to pin 5 of ICZa.
ICZa is a FET (field effect transistor) and is part of a 4007 complementary pair IC (ICZb is the other transistor in the package). Its gate is controlled by mercury switch MS1, a 390kQ
resistor and a 2.ZµF capacitor.
When the mercury switch is open,
the voltage across the 2.2µF capacitor
is zero and so the FET is turned off.
This means that the FET presents a
very high resistance between pins 5 &
4 of ICZa and so no signal appears
across the 10kQ resistor on pin 4.
Conversely, when the mercury
switch is closed, pin 3 of ICZa is connected to the positive supply rail and
the FET turns on. The FET now has
negligible resistance, which means
that the two 10kQ resistors connected
to pins 4 & 5 now act as a simple
voltage divider for the tone oscillator
signal.
Chime effect
The chiming effect is created when
the mercury switch opens again. Initially, the 2.ZµF capacitor is charged
to the full supply voltage (9V) and so,
when the switch opens again, the FET
is held on by the voltage across the
capacitor.
The parallel 390kQ bleeder resistor
-
This close-up view shows how the mercury switches are
installed. Bend their leads at right angles about 2mm
away from the glass bodies before mounting them & make
sure that they are parallel with the edges of the board.
32
SILICON CHIP
now discharges the 2.ZµF capacitor.
As the voltage across this capacitor
decreases, the FET resistance gradually increases, thus giving us a decaying signal amplitude on pin 4 ofICZa.
The result is that the tone volume
decreases to nothing over a period of
about one second.
This sequence of events occurs for
each of the four sections of the circuit, depending on which way you
tilt the case to activate the mercury
switches. The output signals from each
section are then mixed together via
four 10kQ resistors and coupled to
the audio output stage via a 0. lµF
capacitor.
Transistors Ql & QZ form a simple
complementary class AB audio amplifier and this drives an 8Q loudspeaker via a 100µF capacitor. The
two diodes, Dl & DZ, provide about
Mount the mercury switches so that the ends with the
leads sit slightly proud of the PC board. This is necessary
to ensure that all the mercury switch contacts are open
when the project is placed on a level surface.
PARTS LIST
=l
uF
Fig.3: install the parts on the PC board as shown in this layout diagram. Take
care with component orientation & make sure that you don't transpose Q1 & Q2.
The four trimpots (VR1-VR4) allow the tone frequencies to he adjusted.
1.2V of bias between the bases of the
two transistors to reduce crossover
distortion. Without the diodes, each
transistor would be off for the first
0.6V swing of its half-cycle.
Power for the circuit is derived from
a 9V battery via switch S1. The current consumed is approximately
0.9mA with no tone and about 9mA
with tone.
Construction
All of the components except for
the loudspeaker, power switch and
9V battery are mounted on a small PC
board coded SC08103921. Fig.3 shows
the assembly details.
When you first buy or make the
board, check it thoroughly for any
shorts or breaks in the tracks. If you
find any, use an artwork knife or a dab
of solder where appropriate to fix the
problem. It's far easier td do this now
rather than to track down faults after
the board has been assembled.
Begin the assembly by installing
the wire links. It's important to keep
these as straight as possible so that
they don't short out any other components (you can straighten the link wire
by clamping one end in a vyce and
then stretching it slightly using a pair
of pliers).
Next, install the resistors and the
four trimpots. If you are unsure about
the resistor colour codes, check them
using a digital multimeter or refer to
Table 1.
The two signal diodes are the next
to go in, followed by the capacitors
and the two output transistors (Q1 &
Q2). Check the polarity of the diodes
and transistors carefully and make
sure that you don't transpose Ql and
Q2 (one is an NPN type and the other
is a PNP). Similarly, make sure that
you install the electrolytic capacitors
the right way around.
Now for the three ICs. These are
installed in the centre of the board
and all face in the same direction. Be
careful not to overheat the ICs and
make sure that there are no solder
bridges between adjacent pins.
Finally, solder in the four mercury
switches. These must all be installed
so that the end with the leads sits up
higher off the board than the other
end. This is necessary to ensure that
the project must be deliberately tilted
in order to generate a sound output.
As a guide, if you sit the board down
on a flat table, the mercury should
run away from the contact pins in
each case.
By the way, don't play with the
mercury if you inadvertently break
any of the glass envelopes. It's highly
poisonous.
Now that you have finished the
board, check it carefully for solder
splashes, shorts between tracks and
1 PC board, code SC08103921 ,
106 x 58mm
1 plastic zippy box, 130 x 68 x
41mm
4 mercury switches (MS1 -MS4)
1 Dynamark front panel label
1 9V battery snap connector
1 9V battery
1 SPST toggle switch (S1)
1 8-ohm 57mm-dia. speaker
4 1 00kQ horizontal mount
trimpots
Semiconductors
1 4093 Schmitt trigger NAND
gate IC (IC1)
2 4007 dual complementary pair/
inverter IC (IC2,3)
1 BC337 NPN transistor (01)
1 BC327 PNP transistor (02)
2 1 N914 diodes (D1 ,D2)
Capacitors
2 100µ,F 16VW electrolytics
4 2.2µ,F 25VW electrolytics
1 0.1 µF 63VW MKT
4 .022µF 63VW MKT
Resistors (0.5W, 1%)
4 390kQ
233kQ
12 10kQ
Miscellaneous
Screws, nuts, solder, hookup wire,
tinned copper wire for links
missed solder joints. Check also that
all the components are in their correct locations and are correctly oriented.
Testing
When these checks are complete,
you can connect the loudspeaker and
battery to check that the circuit works
correctly. Initially, it's a good idea to
connect your multimeter (set to a
milliamp range) in series with your
power supply. If the current drain
TABLE 1: RESISTORS
I
a
a
a
a
No.
Value
4-Band Code (1%)
5-Band Code (1%)
4
2
12
3901(Q
33kQ
10kQ
orange white yellow brown
orange orange orange brown
brown black orange brown
orange white black orange brown
orange orange black red brown
brown black black red brown
APRIL 1992
33
...... -
I
'
ARGON
LASER
These
cooled
Argon Laser • .•. -_
.f
Heads air
have
had relatively
_
"low hours" of operation.
They are guaranteed. They
·
produce a bright blue beam
:.
(488nM) and have a power
··
output in the 10-100mW range.
Limited supplies, at a small
fraction of their real value.
The head includes power meter circuitry and
·
-
·• _
' t.
"
ONLY
saoo
~l~~i;~o~\dc~~,~~- ;ti~~~t/~i?~a~:;r;ig~~er
supply. We can provide the major components for this
supply. Enquire.
I, I.R. BINOCULAR
VIEWER
Fig.4: this full-size artwork can be used as a drilling template for the front
panel. Drill small pilot holes first, then carefully enlarge them using a reamer.
Suit teachers, doctors,
businessmen, and other
professionals. Improve
and enhance all your
presentations. Not a kit,
but a complete
commercial pen sized
laser pointer at
ONLY
~~r~ndc~~~~~eprice~199
Small pen sized body.
Runs on two small AAA
battery. Battery life: 2-10
hours. Visible 5mW red
(670nM) laser. Projects a
visible red spot at more
than 50 metres. As used
for medical treatment by
doctors and
acupuncturists.
Small black anodised
metal body. Removable
pressure switch . Vertical
and horizontal adjustments. Battery life more
than 10 hours continuous.
SmW 670nM class IIIA
laser. Range is about
150m, some would claim
three times more. Shock
tested to 2000g. One year
warr'l5'~i.v 5 299
Price includes one rifle or
pistol mount
3mW GAS LASER
~~~~7.
1
~i~~c~ra~ i1Wi
Self
powered, and originally
intended to be mounted
on a helmet. Focus is
adjustable from 1 metre
to infinity. Requires some
IA illumination. Powered
by one single 1.SV
battery. Original
,
~~;:g~~~~i~:~_Y
Limited stock.
5
649
I VISIBLE LASER •
DIODE HEAD · ,
Save, by making your
own laser pointer, laser
gun sight, medical treatment laser, etc. Produces
a well collimated beam.
Designed to be powered
directly from a 3V battery,
or from higher voltages, if
a simple constant squrce
is added. Simple circuit
included. 5mW (670nM).
At an incredible
$135
inr\~~d~f'ory
~or the head only: Add
$8 for the extra "bits"
needed to make a
complete laser diode
pointer. Case, switch,
alkaline batteries, and
battery holders.
Everything you need to
make a complete, self
contained, visible laser
pointer or gunsight.
~ l
Includes high quality low
divergence Siemens laser
head with an output at
about 3mW and one of
our reliable and efficient
12V universal laser power
supply kits. The tube is
used but it is guaranteed.
The kit comes with full
instructions and it even
includes a prewound
transformer. The applications include high power
laser pointers, surveying
equipment, optical
experiments, education,
holography, medical
~f~~ia~~citc
exceeds Z0mA, switch off immediately and locate the source of the problem before proceeding further.
If everything is OK so far, try tilting
the board in each direction. You
should hear four distinct tones. If any
of the tones fails to sound, check the
circuitry associated with that particular mercury switch.
Once you have the circuit working
correctly, the four trimpots can be adjusted to produce the desired notes.
You do this by tilting the board in one
direction to close one of the mercury
switches and adjusting the corresponding trimpot until you get the
desired tone.
Adjust VRl for mercury switch
MSl, VRZ for MSZ, VR3 for MS3 and
VR4 forMS4.
Final assembly
The PC board bolts directly to the
lid of the specified case using four
screws and nuts, with extra nuts used
as spacers. Drill these four mounting
holes first, using the PC board as a
template, then attach the front panel
label to the lid and clear the holes
using a sharp artwork knife.
This done, drill the holes for the
loudspeaker and another hole in one
end of the case for the power switch.
In each case, it's best to drill a small
hole first and then enlarge it using a
tapered reamer. The loudspeaker can
now be glued to the lid (behind its
holes) using a suitable adhesive. Wait
until the glue dries, then install the
PC board and power switch and complete the wiring.
The battery sits on the bottom of
the case and can be held in position
using foam rubber when the lid is
attached. Don't forget to switch the
unit off when it is not in use, to preserve battery life.
All that's left now is to find that
frazzled executive. The symptoms
shouldn't be too hard to spot.
SC
As per EA Oct. 91 issue.
Very small size! Complete
kit includes an objective
lens, an infra red image
converter tube, an
eyepiece, an electronics
kit and sufficient plastics
for the case. Very simple
to construct.
ONLi99
ONLY
s299
Melbourne Distributor: Electronics World
(03) 723 3860 or (03) 723 3094
OATLEY ELECTRONICS
PO BOX 89, OATLEY, NSW 2223
Telephone: (02) 579 4985
Fax: (02) 570 7910
Certified p&p: S6 in Aust. NZ (Airmail) : S10
34
SILICON CHIP
Fig.5: here is the full-size etching pattern for the PC board.
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