Portatil Electronics Lab
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RF CIRCUITS TSC Department UPC
Evolutionary
Breadboard A Portable Electronics Lab
A portable electronics lab is presented.It is built around an EVOLUTIONARY PROTOBOARD powered from a computer
USB port.This protoboard is mounted over a plastic plane wich facilitates the setup of experimental circuits
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EVOLUTIONARY BREADBOARD:
A Mobile and Portable Electronic Laboratory
José M. Miguel
RF ELECTRONICS LAB
TSC-UPC CAMPUS NORD
BARCELONA SPAIN
jmiguel@tsc.upc.edu
Abstract: A portable electronics lab is presented.It is built around an evolutionary protoboard powered from a computer
USB port.The protoboard is mounted over a ground plane which facilitates the setup of experiments
Keywords: Portable lab,Electronics lab,Protoboard,Virtual instrumentation
1.Introduction
There`s growing momentum and interest in increasing the
number of students focused on science and information
technology.This kind of students along with radio and elec-
tronics amateurs need hands-on circuitry labs.A conven-
tionally equipped electronic lab is costly and sometimes
only can be used during school hour or session.It is well
known that the real amateur needs his lab available 24 hours
a day.
In this paper,we present a different approach with what we
called a “Portable lab” a complete electronics lab that`s
low cost,minimalist and flexible.It consists of a “Evolu-
tionary breadboard” ,a tester and a laptop or a PC which
provides 5V DC power supply from its USB ports and
virtual instruments like function generators or frequency
meters that run around the sound card of the laptop.
With this lab every student or electronics amateur gets his
setup and tackes individual projects.
2. The classical breadboard
Solderless breadboard are great units for making tempo-
rary circuits and prototyping.Another common use is test-
ing out new parts such as Integrated Circuits
(ICs).Electronic engineers and others scientific people love
breadboards because ease carry out the proof of concept.In
this way they can verify that some circuit idea has the
potential to being used in their designs.
Figure 1. Classical breadboard [1]
A classical breadboard it is shown in figure 1.It consists
of a metallic plate,some binding posts and the most im-
portant, a solderless plastic unit that it is bonded to the plate
by using some screws.The solderless has sets of holes into
which wires can be inserted.Inside each hole,invisible to
you,is a metallic socket appropriate for snugly receiving a
wire pushed into the hole.
Sets of sockets,arranged in rows and columns,are con-
nected together internally as it is shown in figure 2.
Figure 2.Electrical connections in rows and columns of a solderless boar
You plug the wire leads of the components into the
holes to connect them to one another without soldering
2 José M. Miguel
them.The metal plate is painted and therefore the binding
posts are electrically isolated.They are used to connect the
benchtop power supply from two banana cables as it is
shown in Figure 2.Another option is just plug the wires
from a barrel jack or from a 9V battery holder as it is
shown in Figure 3.
Figure 3. A breadboard being powered trough the binding posts from
banana cable [1]
Figure 4.The jack is soldered to two wires that shares the same holes on
the binding pots as the wires going to the power rails of the breadboard[1]
3. The evolutionary breadboard
Figure 5.The evolutionary breadboard
In this section we are going to present an evolutionary
breadboard with better usability than the classical one.In
fact,it can be considered as a portable electronic laboratory
when it is used in conjunction with a multimeter and PC
sound card based virtual instruments.
The new breadboard as it is shown in figure 4. Uses a
PCB as a support plate and incorporates a USB socket that
pulls 5V DC from your computer’s USB port or from an
USB wall charger like the shown in figure 6..Alternatively
you can use the barrel jack or the two female banana con-
nectors to DC supply yours circuits with 9 or 12 volts
The metal side of the PCB plays an important role in the
operation mode of this protoboard.It is used as
ground.The -5V negative terminal of the USB socket,the
sleeves of the female BNC connectors,the black binding
post, the metal case of the audio jacks and the negative
terminal of the external DC power jack are all of them sol-
dered to that ground plane
Figure 6. USB wall charger
One of the botton rails of the solderless board is also con-
nected to ground.Finally the two top rails of the solderless
board are connected to +5V and +external DC respective-
ly.This arrangement gives a lot of easy access to power and
ground in the prototyping space.
The red and black binding pots located at the top right
cornet are used to connect the test leads of a voltmeter.The
red pot is rear connected to a litle black post which is glued
to the solderless board.You can insert a wire in that post
and measure any voltage in the circuit as it is shown in
figure 7.
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Figure 7. How to measure a voltage using a tester
The assembled circuit is a LED and a series cur-
rent-limiting resistor connected from +5v to ground.It is
important to quote that you don`t need an extra wire con-
necting the black banana plug to the ground of the cir-
cui.That is the function carried out by the rear ground plane
of this evolutionary breadboard.
There are two audio jacks in the breadboard.One of
them that can be used to pull a voltage from the headphone
output of the sound card to the circuit that you are test-
ing.The other audio jack is used to establish connection
from the breadboard to the line input of the sound
card.Standart PC multimedia audio facilities offer much
under-utilised potential for scientific and amateur pro-
jects.In Ref`[2] W.A.Steer presents a ready- to- run sound
card- based software frequency-counter, a real–time spec-
trum analyser and a sinewave signal generator,all for use at
frequencies up to 20KHz.(See figures 8,9 and10)
Figure 8. A sound card based frequency meter
Figure 9.A FFT based spectrum analyzer
That voltage can be produced by means a software that
Figure 10.A sound card based generator
It is not advisable to use oscilloscopes based on the
sound card because they have its inputs ac coupled.So any
DC component of the voltage input can`t be displayed.
If you need to test your circuit with an oscilloscope,an
interesting option is the Educational PC Oscilloscope Kit
from Velleman [3].It costs less than 40€,has a bandwidth
from DC to 200KHz and an input range from 100mV to
5V/Div.It needs a USB port and runs under Windows.In
figure 11 you can see this equipment that also works as
transient recorder and spectrum analyzer.
4 José M. Miguel
Figure 11.Educational PC Oscilloscope Kit from Velleman
Model EDU09
If you need a better oscilloscope,Picotech [4] has a great
variety.One of the Picoscope 2000 series can be an excel-
lent option.The evolutionary breadboard has two BNC
sockets to push the signals to the Picoscope inputs as you
can see in figure 12.
Figure 12. The Portable Lab with a PicoScope 2204 and the virtual signal
generator “Generatosaur”
Figure 13.Testing a breadboarded circuit with BasicDSP [5]
4.The Portable Lab
The portable lab provides all you need to set up elec-
tronic circuits.It can be used anywhere and only needs a PC
or laptop with USB connection.
The list of items required consists of:
1-An evolutionary protoboard (see figure 5)
2-A multimeter
3-A little box with compartments for store electronics
devices,resistors,capacitors,ICs,wire jumpers etc.
4-A case for storing tools
5-A case for storing cables (Banana-Banana,Audio)
6-A USB wall charger if you work without PC
7-An oscilloscope like Vellemam EDU09 (Kit)
The complete portable lab it is shown in figure 14.
Figure14. The complete portable lab
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The portable lab can be carried easily inside a briefcase
or iven better inside a cool shoulder bag or a backpack.
Figure 15. The portable lab in a shoulder bag
REFERENCES
[1] How to use a breadboard.
Tutorial Sparkfunk
[2] Sound Card Audio Tools
W.A. Steer
[3] Velleman EDU09
Educational PC oscilloscope
[4] Pico Technology
[5] BasicDSP
[6] COPYBIT
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