Download CricketSat Wireless Sensor

UVM CricketSat Assembly
Manual
Getting Started
• Make a hard copy print out of the following page
• It will help you identify the proper components
• Place the components on top of the matching picture on the
sheet
• Generally, the lowest profile components are added to the
board first
• Many components need to be properly orientated
• Pay close attention to instructions concerning the proper
placement of those components
• Use safety glasses while assembling the CricketSat. Hot
solder and flying leads can injure your eyes.
C1
C2
R4: 100 Ohm
C3
C4
C5
C6
Negative
White
Band
Brown-Black-Brown-Gold
R2: 3300 Ohm
0.1 micro-Farad Capacitors
Black Band
+
-
+
-
+
Orange-Orange-Red-Gold
D2 - Diode
Longer Lead
Notch
47 micro-Farad Electrolytic Capacitors
Pin 1
U3: RF Transmitter
SW1
+
R3: 680 Ohm
Dimple
1
2
3
4
DIP
Socket
Blue-Gray-Brown-Gold
8
7
6
5
U1: 555
Timer
IC
D1
U2
R1
Flat Side
Up
Pins: 1 2 3
Pins: 1 2 3 4
On/Off Switch
5-Volt
Regulator
10K Ohm
Thermistor
B1: 9-Volt Battery
Printed Circuit Board (PCB)
+
Red Lead is Positive
Battery Snap Connector
Antenna Wires
-
+
Longer
Lead
+
Light
Emitting
Diode (LED)
Printed Circuit Board
• Metal layers - conductors
–
–
–
–
Front and back sides
Epoxy board - insulator
Traces provide the wiring
Via holes - connect the front
and back metal layers
• Front side of board
– Components on this side
– White silkscreen layer
• Component outlines
• Reference designators
– Green solder mask layer
• Insulates exposed metal
• Back side of board
– Solder on this side
Assembly Techniques
• Inserting Devices
– Bend leads if necessary to ease
insertion into board
– While pressing component to
board, bend leads at an angle
– This will hold components in
place while soldering
– Just 4 or 5 components at a time
45 degree angle is best
Bend lead close to board
• Soldering
– Use enough heat
– A shiny Hershey’s Kiss shape
• Snipping leads
– Flying leads may damage eyes!
– Hold lead while cutting or point
downward
Snip just above solder joint
Resistors and Diode First
D2 - Orange Diode
(Black Band to the Left)
R4 - 100 Ohms
R3 - 680 Ohms
R2 - 3300 Ohms
Clip leads after this step...
Small Capacitors and Battery Clip
Route wire down through
these center holes
Solder wire to
these outer holes
Top View
Install Battery Clip
Red +
Black -
Bottom View
•Feed 2 inches of wire
down through strain
relief holes, from top side
of board
•Push bare wire ends
completely up through
solder pad holes from
bottom side of board
•Pull excess wire tight.
Should look like this…
Install Capacitors
C4, C5, C6
•Solder connection on
top side of the board
0.1 uF
•Trim excess wire on top
of board
Clip leads...
No Bare Wire Allowed
DIP Socket
•Align socket with white
outline provided on board
•Place the notch up,
towards C4
•On/Off Switch outline for
next step...
•Use the vise alligator clip to hold the socket in place or press flat
against table surface while soldering
•Make sure that socket is flat to the circuit board and that all the
pins emerge from the backside of the board before soldering in
place
On/Off Switch
Solder all eight pins of
the switch
•Use the vise alligator clip to hold the switch in place or press flat
against table surface while soldering
•Make sure that switch is flat to the circuit board and that all the
pins emerge from the backside of the board before soldering in
place
Installing the Taller Parts
U2 - Voltage Regulator
Push only half-way into board
Install these Parts...
•C1, C2, C3 -Polarized
•White band (-) to outside of
board
•U2 - Orientation
•Flat side left, towards C3
•Push only half-way into board
•D1 LED -Polarized
•Longer lead (+), next to socket
Make sure capacitors are mounted
close to board surface to minimize
movement
Clip leads...
Install the Antenna Wires
•There are four antenna holes
•Wires are soldered to the outer two holes,
and pass through the outer two
•Strip ½” of insulation from end of wires
•Insert a bare wire end from the bottom
side of the board through one of the two
outer white-circled antenna holes
•Rest it on a table surface as shown left
Top View
•The weight of the board should insure that
all of the bare wire extends through the
top of the board
•In this position, solder the connection on
the top of the board as shown
No bare
wires
•Repeat for the other wire
•Feed the free ends of the wires through
the inner strain relief holes from the
bottom side of the board
through the
strain relief
holes
Bottom View
•Pull tight and snip excess bare wire on
top of board
Transmitter and Timer IC
Transmitter Module
•Install the transmitter as shown to the left
•Metal can faces towards antenna
•Make sure the module is soldered close to
the board to minimize movement
Clip your leads...
555 Timer IC
•Locate Pin 1 on the IC, marked with a
“dot”
•This end of the IC goes next to C4
•Straighten pins if necessary and press into
socket
•If pins bend while inserting into socket,
remove IC and straighten pins.
Finally, the Thermistor
•Stands up above other circuits
•Use the black plastic insulation that you
stripped from your antenna wires in an
earlier step
•Slide insulation up to the body of the
thermistor in order to insulate the leads
•Insulation prevents “short circuits” to
other exposed metal leads
Solder at location R1
on the circuit board
Short Circuit Test
•We want to make sure that there are no
short circuits on the board
•Performed before connecting the battery
for the first time
•Set the meter to the OHMS setting
•Touch the meter leads to the battery
connector as shown
•Meter should indicate an open circuit
•Reverse the test leads and measure again
•Should be an open circuit reading again
Live Test
•Connect the 9-Volt battery
•Observe the LED, it should be
flashing around 1-2 Hertz (times per
second)
•RF Test: Use a UHF radio receiver
tuned near 434 MHz to hear pulses
•Optional: Measure the voltage on
the V+ and 5V test points
Congratulations on your successful assembly!
Primary Features
Prototype
Development Timing
Area
Capacitor
555
Timer
IC
5-Volt
Regulator
IC
On/Off
Switch
Dipole
Antenna
9-Volt
Battery
Leads
RF
Transmitter
Module
Test
Points
Thermistor
Flashing
LED
Timing
Resistor
Secondary Features
Noise
Decoupling
Capacitor
Output
Jack
Series
Isolation
Resistor
Protection Diode
(Reverse Battery
Connection)
Current
Limiting
Resistor
(LED)
Noise
Decoupling
Capacitors
Noise
Decoupling
Capacitor