POPEYE

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Front of POPEYE, showing the Pi Camera.

POPEYE is a HAB Payload designed to downlink Live Pictures using SSDV.

A prototype of this payload was demoed in the Introduction to High Altitude Ballooning talk I gave at the BATC Convention 2013. It was also intended to be launched at the Convention but the Launch was cancelled due to adverse weather.


GitHub Code Repository: https://github.com/philcrump/pi-tv


SUSF Flight from Cambridge - 5th April 2014

This payload flew on one of the two Southampton University Spaceflight Society Outreach Flights on the 5th April. It reached 38.5km in altitude. Despite a difficult launch in high wind, the payload performed well apart from a minor bug in the temperature overlay that didn't correctly parse negative temperatures.

Capabilities

An SSDV Image received with dl-fldigi in testing
  • 434.200 MHz 600 Baud RTTY Downlink
    • 400x256 JPEG Images with FEC
    • Sensor Data Overlay
  • Locally stores 1920x1080 PNG images
  • Estimated 4 hours battery life on single 9V PPA.
    • Diode-OR power available to power from external source during prep before launch.

Hardware

Payload internals, with standard Alkaline 9V Battery.

CPU

  • Raspberry Pi Model A

Sensors

  • Pi Camera (non-IR)
  • 2x DS18B20 Temperature Sensors - Datasheet

Transmitter

  • Radiometrix NTX2B 434MHz Transmitter - Datasheet

Power

  • 3.3V 600mA Buck Regulator - Info
  • Energizer Ultimate Lithium 9V Battery, 750mAh - Datasheet
  • 2x Schottky Diode-OR to allow use of external power source

Picture Sizes

An 8GB SD Card will be used for the flight.

SSDV Size

"/usr/bin/raspistill", ['-n','-w','400','-h','256','-t','6000','-e','jpg','-q','90','-mm','matrix','-o','ssdvpics/'+picCount+'.jpg']

  • 80-120KB / pic
  • 8-12KB / rxed pic

Full Resolution

"/usr/bin/raspistill", ['-n','-w','1920','-h','1080','-t','5000','-e','png','-mm','matrix','-o','bigpics/'+picCount+'.png']

  • Snapped every 6 seconds
  • 3.1MB / pic
  • 1860MB / hour
  • 7.4GB / 4-hour prep+flight

Power Consumption

Measured at 8V (nominal battery voltage) into the Step-Down Regulator.

Using a Raspberry Pi model A

  • 60mA with NTX2B running
  • 160mA with Camera + NTX2B running (50% Duty Cycle)

Average draw: 110mA which means ~7 hours off 1x 9V PPA cell!

Using a Raspberry Pi model B with ethernet active (ssh control session)

  • 190mA with NTX2B running.
  • 290mA with Camera + NTX2B running (50% Duty Cycle)

Using a Raspberry Pi model B with ethernet unplugged

  • 150mA with NTX2B running.
  • 250mA with Camera + NTX2B running (50% Duty Cycle)


Photos