CricketSat Assembly Manual. CricketSat Background Developed at Stanford University –Space Systems Development Laboratory Part of the NASA student satellite.

CricketSat Assembly Manual

CricketSat Background• Developed at Stanford

University– Space Systems Development

Laboratory

• Part of the NASA student satellite program– Teach fundamentals of space

hardware development– Space Grant Fellowship Program

• Funded support• Vermont Space Grant

Consortium (VSGC)– UVM campus

Student Satellite Programs• CricketSat

– Lowest cost - disposable

– Live telemetry

• BalloonSat– Larger balloon

– Expensive instruments

– GPS tracking system

• CanSat– Dropped by parachute from plane or rocket

– Many instruments

– Live telemetry

– Test bed for CubeSat

• CubeSat– Earth-orbit satellite

Getting Started

Your Parts Kit• Your kit contains parts for

two CricketSat sensors

• They are all mixed together in the same bag

• The second unit will not have an RF transmitter or antenna

• The second unit may be used for your final project

Prepare for Assembly• Make a hard copy print

out of the following page

• It will help you identify the proper components

• Place the components with the matching picture on the sheet

• T.A. sign off

TA:

C1 C3C2C4 C5 C6

U2R1

D1DIP

Socket

Notch

U1: 555 Timer

IC

Dimple

Pin 1

Flat Side Up

1 2 31 2 3 4

8765

1234

U3: RF Transmitter

5-Volt Regulator

10K Ohm Thermistor

Printed Circuit Board (PCB)

47 micro-Farad Electrolytic Capacitors

Longer Lead

+ - + - + -

Longer Lead+-

Light Emitting

Diode (LED)

0.1 micro-Farad Capacitors

+-

Black Band D2 - Diode

+-

B1: 9-Volt Battery

Pins: Pins:

Antenna Wires

Battery Snap Connector

+

-

Red Lead is Positive

R4: 100 Ohm

R2: 3300 Ohm

R3: 680 Ohm

Brown-Black-Brown-Gold

Orange-Orange-Red-Gold

Blue-Gray-Brown-Gold

Negative White Band

Printed Circuit Board• Metal layers - conductors

– Front and back sides

– Epoxy board - insulator

– Traces provide the wiring

– Vias - 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

• Soldering– Use enough heat

– A shiny Hershey’s Kiss shape

• Snipping leads– Flying leads may damage eyes!– Hold lead while cutting or point downward

Bend lead close to board

45 degree angle is best

Snip just above solder joint

Resistors and Diode FirstD2 - 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

Install Battery Clip

•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…

•Solder connection on top side of the board

•Trim excess wire from connection

No bare wire allowed!

Route wire down through these holes

Solder wire to these holes

Bottom View

Top View

+ RED

- BLACK

Install Capacitors

C4, C5, C6

0.1 uF

Clip leads...

DIP Socket

•Use the vise alligator clip to hold 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

•Align socket with white outline provided on board

•Place the notch up, towards C4.

Installing the Taller Parts

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

U2 - Voltage Regulator Push only half-way into board

Clip leads...

Install the Antenna•There are four antenna holes

•Wires are soldered to the center two holes, and pass through the outer two

•Insert a bare wire end from the bottom side of the board through one of the two center marked antenna holes

•Rest it on a table surface as shown left

•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

•Repeat for the other wire

•Feed the free ends of the wires through the strain relief holes

•Pull tight to set as shown

•Snip excess bare wire on top of board

No bare wires through the strain relief holes

Transmitter and Timer IC

•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

•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.

Clip your leads...

Transmitter Module

555 Timer IC

Finally, the Thermistor•Stands up above other circuits

•Search parts bag for two pieces of black insulation

•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

•Contact your T.A. before connecting the battery

Live Test•Connect the 9-Volt battery

•Observe the LED, it should be flashing around 1-2 Hertz

•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

TA: Sign-off on Parts SheetCongratulations!

Prototype Development

Area

Thermistor

Test Points

Dipole Antenna

RF Transmitter

Module

Timing Capacitor

5-Volt Regulator

IC

555 Timer

IC

Flashing LED

9-Volt Battery Leads

Timing Resistor

Primary Features

Output Jack

Noise Decoupling Capacitor

Series Isolation Resistor

Current Limiting Resistor (LED)

Noise Decoupling Capacitor

Protection Diode (Reverse Battery

Connection)

Noise Decoupling Capacitors

Secondary Features