Off-world Power Generation Lab 1: Free Space 1W Transmission

Overview

[large panel] > [regulator] > [battery] > [pi]                    SPACE
                                        > [regulator] > [laser]   =====>   [small panel] > [regulator] > [battery] > [arduino]

• Use a full-sized solar panel to power a large battery through a commercial regulator.
• Use the large battery to power a raspberry pi.
• Use the large battery to power a small laser through a voltage regulator that reports the delivered power.
• Add an on/off switch to the laser circuit that is controlled by the pi.
• Point the laser at a diffraction lens that illuminates a small solar panel.
• Use the small solar panel to power a small battery through a voltage regulator that reports the delivered power.
• Use the small battery to power...
  • something simple, a fan or a light, through a usb multimonitor
  • an arduino that can monitor the voltage and current
  • a lan-connected raspberry pi that can monitor the energy and call an API to report snapshot values.

Remember: we regulate the voltage, everywhere. Only voltage can force current where it is not wanted.

Gear

Primary

• 100W solar panel 16V 6.25A ("open circuit voltage" 20V)
• solar power regulator - I have no idea if this will do the job yet... but it's on the way!
• 88 Wh battery
• fully-configured raspberry pi 3, hostname Lime
• $45 300mW laser
• small solar panel
• 15 Wh battery
• Arduino Uno

Secondary

• arduino starter kit
• Multimeters
  • Etekcity cheap but well-rated all-in-one multimeter
  • USB multimeter (DROK)
  • USB multimeter (PowerJive)
  • leads and clips kit
• 190-540nm laser goggles for our 405nm laser
• lots of experimental voltage regulators, what works is still TBD
  • Winners® 7A DC 60V Adjustable Step Down Regulator
  • LM317 on a board with a dial
  • a bag of LM317T Adjustable Regulators really popular, need heatsinks!
  • Ultra Low Voltage Boost Converter i looked hard for a very-low-voltage booster, will this work? the 5V booster of projects i found is no longer avail
• Arduino Compatible Expansion Board
• a full power supply kit, probably good to build-and-learn, and also probably very useful
• uugear witty pi mini x2 to turn the pi on/off on a timer - hopefully i can use the arduino instead but it's an option
• Breadboards
• USB cables and adapters

More

• cheap <$1 5mW laser
• fully-configured raspberry pi 3, hostname Carambola
• bare Arduino Uno

Connectors

• large panel uses MC4 connectors: we got a bunch of connectors to splice wire into
• commercial solar regulator: raw wire input/output
  • Output: 12V Battery (make sure to config to use 12V not 24V)
  • Input: Max solar Panel Power: 360W
• large battery
  • some sad Japan Jack Input: 14-25V, 3A
  • USB Output: 5V/2A USB (12V/6A, 16V/5A, 19V/4.5A, 24V 3.5A??) - USB QC: 5V/3A, 3.6V-12V, 18W Max.?) wtf
• laser power: raw wires - replace power supply with an inline resistor??
• small battery uses USB out, microusb in: we got a bunch of usb connectors and cables
  • Output: 5V/1A USB
  • Input: 5-6V/1A MicroUSB

Goals

• monitor delivered power - "homemade" Peltier Calorimeter
• keep the arduino powered 24/7
• add an interesting load at the far end
• put a pi at the far end to read and report power
  • forum notes on getting digital power read on pi
  • measure pi voltage via an arduino would be excellent to pull off, we could report it via an API call to a bitpost service
• make the pi sleep
  • use an arduino! uugear explanation
  • if arduino is a pita, use witty pi 2 or witty pi mini board with pi, it runs its own clock, can turn raspberry pi on/off, can pulse battery supply to keep it alive, should make a sleeping pi arrangement SO MUCH easier [1] mini pinout

TODO

• understand what the laser needs; see here perhaps and more from him
• need POTENTIOMETER(S) (variable resistance) to adjust power to laser
• all the regulators
• more breadboards, perfboards, any needed soldering thingees
• pi uses some adapter bullshit
• arduino is also a pita
• consider this sparkfun boost converter, handles low power

Performance

Solar collection efficiency: 6.4kg 100W panel = 15.6 W/kg

Solar collection cost: $115 100W panel = $1.15/W

Solar storage efficiency: 88.8 Wh $129 Voltaic lipo battery, weighs ?? 2kg? ~ 44 Wh/kg

Solar storage cost: 88.8 Wh $129 Voltaic lipo battery = $1.45 / Wh