Rocket computer

What kind of electronics are small enough to fit into a small hobby model rocket vehicle? Long and skinny, to fit in those rocket tubes.

• Altus Metrum has open hardware and software designs for high powered model rocketry avionics solutions, such as the TeleMetrum altimeter with integrated telemetry link.
• "Taniwha Flight Computer" by Paul Campbell: "the DAC is no longer easily available - we need to lay out a new board for a more modern part"
• "Small Altimeter for Model Rockets" by Herve Cousin
• rocket timer (found via rocket timer) (uses TC4422 "9 A mosfet driver" to power the igniter; but first uses the PIC16F84 to delay the right time ... what are the *other* connectors on the board for?)
• "A miniature 2 meter beacon for rocketry and balloons" by KB0VVQ; "beacon"; "... The tricky bit is running the PIC off the same oscillator. ..."
• "Beeping" Tracking Transmitter Kit
• directional antenna for inexpensive pocket radios
• "Radio Locator Beacon for Flying Objects" by Dan Gravatt 2009 "It weighs about an ounce with its 12-volt A23 alkaline battery ... 9/16" inches wide to fit inside an Estes BT-20 tube ... If the spring-loaded terminal of the battery holder is "down", when the rocket launches the acceleration will cause the battery to compress that spring, turning off the transmitter."
• "Rocket acceleration logger": ATTiny13 logging data from a 3-axis acceleration sensor -- a Freescale MMA7260 scavenged from an off-brand Wii Nunchuck -- to a 32KByte 24C256 EEPROM. All the electronics much smaller than the small Li-ion battery powering it. It survived the trip and a fall into mud (with no parachute!).

DavidCary is designing a "small rocket computer" that can fit inside an off-the-shelf small model rocket, rather than requiring a "high powered model rocket". One that is as narrow as a 13 mm "mini engine", narrower than a 14 mm AA battery, much less a 18 mm "standard engine".

ideas:

• accelerometer to log the accelerations during flight.
• pressure sensor to measure barometric altitude
• beeper to help find it
• ...
• What other electronics would be useful to put into a small hobby model rocket?
• ...

Once has measured the maximum barometric altitude (and other data), how should it communicate that to us? Some communication options are:

• Re-use the direction-finding beacon as a RF Morse code transmitter. Use ordinary radio to listen.
• Put little blinky lights on-board -- blink out Morse code, or use a binary-clock-like lightbar or miniature 7 segment LED display.
• Put a tiny LCD display on-board.
• Drop the rocket computer into a "cradle" with a LCD display.
• Put a standard socket on-board. Plug a cable between the rocket computer and a standard laptop. RS232 on RJ11? RS232 on TRRS plug? Micro-USB?.

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• Recovering data from a rocket-mounted accelerometer