Kinetic project
Turn motion into light
Due: Generator demo in Week 3 (Feb 6), project presentation in Week 5 (Feb 20).
Details
We begin the hands-on work of the class with a literal hands-on assignment: turning cranks to generate electricity. Any relative motion between magnets and conductors will induce electrical current in the conductor. Thus electrical motors are also electrical generators, and you can use this fact to easily power things with motion. A relatively forgiving thing to power is an LED.
The kinetic project challenge is to turn motion into light. Play around with a few alternatives for generators (say, stepper vs DC gearmotor). What is the open circuit voltage and short circuit current of your generator? Is the output AC or DC? Consider various forms of physical input (say, hand crank vs. foot pedal). How hard is it to turn? What physical activity is the input, and what human muscles or other motion does it capture?
Condition the output of your generator to safely power (at a minimum) a light, which could be a single bulb (of any type) or a more complex display. Consider the efficiency of the light source in lumens per watt.
Awards will be given for Brightest Light, Most Fun Input, and Most Salvaged Materials.
Work individually or in groups of up 3. Document your project in detail, with measurements; show off generators in class in week 3; and formally present the project in Week 5, February 20.
Do’s & Don’ts
- Do use electromagnetic induction
- Don’t use piezo- or peltier-effect devices, or other alternate sources, unless we discuss them first
- Do use large forces (e.g. big muscles/gestures)
- Don’t use tiny, minute forces (keystrokes, tap water)
- Do spend extra time designing the mechanical aspects of your build – this is harder than the electrical aspects IMO
- Don’t forget to have fun!
Kinetic Learning Goals
- Understand relationship of current, voltage, and power in electricity intuitively and quantitatively
- Understand relationship between power, energy, and time
- Calculate kinetic energy of moving objects
- Calculate gravitational potential energy
- Review physics concepts such as force and work
- Measure electrical current with a multimeter
- Apply concepts of short-circuit current and open-circuit voltage
- Measure electrical power and energy with specialized measurement tools
- Learn about electromagnetism and induction
- Understand alternating and direct current
- Build a rectifier circuit
- Lumens per watt and efficiency generally
- Learn about role induction plays at grid-scale electricity production.
- Learn relationship between kinetic and thermal energy
- Learn about heat engines, thermodynamics, and Carnot efficiency
- Appreciate function of capacitors for energy storage and energy smoothing
- Understand power density, energy density, specific power, and specific energy
- Calculate energy stored in capacitor
- Understand voltage regulation and DC-DC conversion
- Understand the capacity factor and nameplate rating of a generator
- Gain an intuitive feeling for the relationship between mechanical work input and electrical output
- Consider energy technologies at all scales in human-work-equivalents (Fuller)
- Understand role of muscle power and natural energy sources in human history
- Begin to see scope of challenge in decarbonizing electricity and electrifying everything
Solar project
Turn light into computation
Due: MVP Demo Week 10 (April 3), full project* Week 14 (May 1)
Details
I’m very excited that this year, we have amazing support from our neighbor, Voltaic! Voltaic is a Brooklyn-based company that makes excellent solar panels and battery packs optimized for off-grid IoT projects. To do this right is expensive, so their hardware is a little out of reach for most student projects. However, not only are they helping us by loaning their best-in-class components, but they are also giving us space to set up outdoor projects in the Navy Yard.
Starting in week 6, you will work to create a project that lives “off-grid” and survives only on solar power. We will visit Voltaic in the Navy Yard on March 6, week 7, and you will have occasional – but not 24/7 – access to the site after that.
A basic version of the projects will be presented in week 10 (April 4). If you choose to develop a more complete solar project for your final, that version will also be shown in week 14 (May 1).
Your solar project must:
- Run continuously for 5 or more days on solar power.
- Mount securely to a structure and survive outside.
- Report, at a minimum, status information such as battery and/or panel voltage to a central data site.
- Run a payload of your design – this could be a sensor, art installation, or really anything, as long as you have a realistic energy budget for the payload and it is matched to the available solar power.
Solar Learning Goals
- Appreciate sun as ultimate origin of almost all terrestrial fuels and energy sources
- Touch on nuclear fusion and fission
- Know the value of the solar constant and AM1.5 solar flux value
- Learn basics of photovoltaic (PV) conversion of light to electricity
- Learn about specific materials and considerations that affect PV
- Learn about emerging technologies in PV such as perovskites and quantum dots
- Learn about the difference between grid-tied and off-grid PV
- Learn about the additional components needed for both types of PV
- Learn about energy storage in batteries
- Apply energy storage concepts from capacitors to batteries (specific energy, etc)
- Learn about different battery chemistries and other factors that affect battery performance
- Learn about grid-scale battery energy storage
- Learn about grid-scale PV installations
- Appreciate difference between PV and solar-thermal power
- Build a realistic power budget for a project
- Apply methods for reducing the energy consumption of your projects
- Design projects that tolerate intermittent or irregular power supplies without faults
- Design a project that can realistically survive outdoors
- Test solar panels using concepts of OCV and SCC
- Understand MPP in PV and Jeff’s rule-of-thumb for MPP