1. The BalloonSat Development Board
Programming Unit, Lecture 1
LSU 09/19/2013
BalloonSat Development Board

2. BalloonSat Development Board
Background
The LaACES BalloonSat Development Board evolved from CanSat, developed by Professor Bob Twiggs at Stanford University’s Space Science Development Laboratory.
CanSat was designed to be accommodated within a soda can sized satellite enclosure.
CanSat featured a BASIC Stamp micro-controller, an additional memory chip for data storage and a modem for connecting to an external radio transmitter/receiver.
LSU 09/19/2013
BalloonSat Development Board

3. From CanSat to BalloonSat
ACES payloads did not need the modem of CanSat.
No on-board analog-to-digital converter for sensors.
Expanding CanSat with external electronics was inconvenient. LSU designed add-on prototype board.
CanSat
LSU 09/19/2013
BalloonSat Development Board

4. BalloonSat Requirements
LaACES BalloonSat designed to include
BASIC Stamp micro-controller
EEPROM memory for data storage and retrieval
Analog-to-Digital converter
Real Time Clock with provision for battery backup
Prototyping area
Expansion capability
Suitable for laboratory activities, payload applications
LSU 09/19/2013
BalloonSat Development Board

5. BalloonSat Development Board
BalloonSat Features
BASIC Stamp BS2P24
24LCxx EEPROM
Real Time Clock
4 channel ADC
V ref for ADC
Temperature sensor
4 LED indicators
prototyping area
expansion connector
BalloonSat
LSU 09/19/2013
BalloonSat Development Board

6. BalloonSat EEPROM Memory
24LCxx series CMOS Serial Electrically Erasable Programmable Read Only Memory (EEPROM) is supported.
Synchronous serial interface, I2C compatible.
The 24LC64 provided is a 64K chip organized as 8 blocks of 1K x 8-bits.
Data retention of at least 200 years. Erase/write cycles > 105
LSU 09/19/2013
BalloonSat Development Board

7. BalloonSat Real Time Clock
Dallas DS1302 Time keeping IC.
Synchronous serial interface.
Registers for Year, month, day, hour, minutes, seconds.
Includes on-chip 31 x 8 bit RAM for scratchpad data storage.
Low power requirements
LSU 09/19/2013
BalloonSat Development Board

8. Analog-to-Digital Converter
BalloonSat includes a 4 channel ADC, ADC0834
MICROWIRE synchronous serial interface
Precision voltage reference AD780
Selectable 2.50 or 3.00 VDC reference for ADC
On-chip temperature transducer
On board operational amplifier for buffering and scaling temperature transducer output.
Temperature signal can be connected to ADC channel 3.
LSU 09/19/2013
BalloonSat Development Board

9. Prototyping on BalloonSat
Prototyping area features GND and VCC busses.
Pads for BASIC Stamp I/O pins P0 - P15
Pad and bus layout is compatible with DIP IC’s (0.300” wide).
GND and VCC testpoints
Prototyping Area
LSU 09/19/2013
BalloonSat Development Board

10. BalloonSat Development Board
Expanding BalloonSat
BASIC Stamp I/O pins are brought out on expansion connector .
Use of I/O pins must be planned to avoid device contention.
LSU 09/19/2013
BalloonSat Development Board

11. BalloonSat Development Board
Flying BalloonSat
Flying BalloonSat in a student balloon mission requires some special considerations not encountered on the lab bench.
Battery power required
Low temperature and pressure environment
Suitable batteries for main power and for RTC backup
Integrity of connections
for flight applications, direct soldering of cables may be more reliable than connectors.
Jumpers should be soldered or secured in place.
LSU 09/19/2013
BalloonSat Development Board

12. BalloonSat Development Board
Activity P1
Identify and inventory parts in the BalloonSat kit.
Assemble BalloonSat following instructions in manual.
Perform functional tests (It’s all in the manual.)
LSU 09/19/2013
BalloonSat Development Board