Download Building a NearSys BalloonSat Easy v3.2 Flight Computer (slightly

Building a NearSys
BalloonSat Easy v3.2
Flight Computer
(Fall 2010 modifications)
AEM 1905: Spaceflight with Ballooning
University of Minnesota
BalloonSat Easy 3.2 kit and instructions
Parts in BalloonSat Easy 3.2 (modified) kit
Printed Circuit Board (PCB)
Resistors, to be numbered R1 – R9
Diodes – polarity indicated by the stripe
9-volt battery snap for main power
(rather than using AAA battery holder)
Wires for switches, LED’s, commit pin, etc.
Toggle switches for main power and servo
Heat-shrink tubing (AKA shrink-wrap)
IC’s (AKA chips) and sockets
Capacitor – polarized; longer lead is positive
5-volt voltage regulator
Power indicator LED’s; flat edge is negative
Reed relays to fire cameras (if needed)
Headers (male) and receptacles (female)
Audio jack to be shorted and used
as a Pull-Before-Flight “commit” pin
AAA battery packs for power
(not used in modified version)
Identify which resistors are which (using
multimeter or color codes) then solder
in R1 – R9 in exact locations. Clip leads.
Solder in diodes – watch strips for polarity
Solder in 9-V battery snap for main power
only. Use the strain relief holes in the PCB.
Be sure red is positive, black is negative.
Cut 4 pieces off long wire then strip
ends of each to about ¼ inch length.
Solder wires to main power and commit
pin. Make use of strain relief holes.
Slide on shrink wrap then hook the switch
wires to the center post and one side post
of switch. Solder. Slide up wrap. Shrink.
Increase stripping on commit pin leads
to ½ inch. Slide on pieces of shrink wrap.
Wrap wires through two tabs on audio jack
Solder then cover with shrink wrap
PCB with switch, audio jack, & battery snap
Other main modification: put headers on
LED’s (2), camera outputs (2), and the
servo switch & power (won’t use often)
Can use a receptacle (or helping hands)
to hold header in place while soldering it.
Don’t overheat – they melt! Heat sink!
If working alone you may need to use
the helping hands to hold the solder
(if your hands are both busy elsewhere)
Snip leads of one LED for a main power
indicator. Cut 2 more pieces of wire.
Solder to LED and cover with shrink wrap.
When soldering 2-hole receptacle to
LED wires, heat sink to helping hands
through a 2-pin header (temporarily)
Add 2-hole receptacle to LED wires
so it can plug onto LED 2-pin header
Insert 2 IC sockets in PCB – watch notches
Solder in the capacitor – watch polarity
Insert voltage regulator – watch polarity
Avoid solder bridges on closely-spaced
pins, like those on the voltage regulator
Insert REED relays – only go in one way
Make sure the 3-pin male servo header
(with short ends through PCB) and the 3x3
receptacle can fit next to each other. If too
tight, sand down receptacle (see next slide).
Sand down one end of the 3x3 hole
receptacle if necessary to make it fit
Insert the 1x5 receptacle nearby
Insert 3-pin programming header
Cut a shorting wire to modify the audio
plug for use as a commit pin. Note the
two ends are stripped different lengths.
Wrap two ends of the shorting wire
around the audio plug tabs as shown
Before soldering the shorting wire
in place, be sure the cover still fits on
Solder shorting wire in place. Put
on cover. Strengthen with hot glue.
BalloonSat Easy 3.2 flight computer,
without chips, ready for testing