On Porch Lights, Optical Geometry and the Ignition Point of Eyebrows

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Discussion Overview

The discussion revolves around the feasibility of using mirrors to focus a neighbor's porch light, which is described as having a high intensity, to raise the temperature to the ignition point of the neighbor's eyebrows. The conversation includes considerations of optical geometry, potential solutions to light nuisance, and personal anecdotes related to bright lights from neighbors.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant outlines a hypothetical scenario involving mirrors to focus a neighbor's porch light, detailing specific dimensions and assumptions about the setup.
  • Another participant shares a personal experience from the "Light Wars," suggesting that a slight curvature in the mirror could help concentrate the light back towards the neighbor's window.
  • A different perspective proposes using blackout curtains or creating a shade for the neighbor's light as a simpler solution, while also mentioning the potential of using a powerful floodlight with a parabolic reflector.
  • Another participant humorously suggests building a light-activated switch for various disruptive devices, while also recommending a simple request for a shade as a practical approach.
  • One participant references historical accounts of Archimedes using mirrors to focus light, suggesting that this scenario could be a modern equivalent of that concept.
  • A participant empathizes with the original poster's situation, sharing their own experience with excessively bright floodlights from neighbors, noting that while they are bothersome, they do not directly shine into their windows.

Areas of Agreement / Disagreement

Participants express a range of opinions on how to address the issue of the porch light, with no consensus on the best approach. Some suggest technical solutions involving mirrors, while others propose simpler alternatives like curtains or shades. The discussion remains unresolved regarding the most effective method to deal with the light nuisance.

Contextual Notes

The discussion includes various assumptions about the physical setup and the properties of light, as well as personal anecdotes that may not directly relate to the original problem. There are unresolved aspects regarding the effectiveness of proposed solutions and the practicality of the hypothetical scenario.

DaveC426913
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Statement of the problem:
How many bedroom mirrors (of nominal dimensions six feet by one feet) are required to focus my neighbor's porch light with sufficient precision to raise the temperature to the ignition point of my neighbor's eyebrows?

Setup:
  • living at this address for exactly one month today,
  • neighbor has a porch light of approximately 10 million candlepower
  • the porch light is line-of-sight to my bedroom window, distance: 30m
  • light is on a motion sensor whose sensitivity is on the "molecules" setting
  • duration is "Longer Than Any Sane But Sleepless Person Would Think Possible"
  • line-of-sight to my property is bounded by wall of neighbor's house and by my property lines (see diagram)
  • we can ignore airspace regulations, 30m height should be well below flight paths
  • the 3m easement across the back of my property can likewise be ignored, as it only restricts building of permanent structures, and I expect to take the scaffolding down once my neighbor's eyebrows are well and truly melted off
  • assume bedroom mirrors are flexible enough to be bent circular with a radius of 30m. This will give a lit area of 1 foot wide by some arbitrarily small height.
  • If more concentration is required, I can split the mirrors vertically to make six inch by six foot mirrors. Anything narrower than six inches is unnecessary, since that it the lower limit of typical eyebrow (full set) width.
  • assume light and neighbor's eyebrows are effectively co-incident
  • assume neighbor is spherical and in a vacuum (and - if a chicken - at least six feet tall)

The porch light:
1688253726318.png


The image of my hand on my bedroom wall by porch light:
1688253762803.png

(in the morning I will find my hand just slightly more tanned than the rest of me)

The configuration:
1688253821189.png
 
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I have relevant experience, since I was involved in the "Light Wars" about 30 years ago. Neighbors across the bay installed a very bright floodlight on the top of their cottage. It was aligned so that the edge of the beam lit up their beach, and the main beam lit up my friends beach. They turned it on for the first time when some of my friends were skinny dipping.

Multiple requests to realign it were ignored. So we installed a 1000 watt floodlight aimed at them, and turned it on when their light was on. There was some yelling the first few times this happened, then they got the idea and (I forget) either realigned or removed their light.

A fact bearing on the problem is that the neighbors had a very expensive three story cottage. My friends had a 500 square foot cottage in a group of five cottages that shared 50 feet of beach. The five cottages were built as a resort in the 1920's.

It looks like your bedroom window is nicely aligned to put in a mirror to reflect his light back into his window. Maybe you could pull a slight curvature into your mirror to concentrate the light somewhat.
 
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A cheaper solution: Black-Out curtains, or offer to buy/make them a (custom?) shade to shadow your bedroom

(although I DO like the 1kW flood light; maybe with a parabolic reflector added
[edit] try searching for Parking Lot Lights, there used to be 1kW incandescents made for them, works only if their bedroom faces you[/edit])
 
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I shouldn't even go there but does his bedroom face your house? It is not difficult to build a light actuated switch which could control a host of items.....spotlights, lasers, intruder sirens, a vortex gun to rattle only his windows... But perhaps a simple request for an intervening shade on the light could work? That being said LED spotlights run long and cool
 
I know your pain, Dave. My neighbors moved in last year and installed super bright floodlights over their shed and on the front of their house. They are obnoxiously bright. The only reason I haven't complained to them is because the lights don't shine directly into any of my windows in such a way as to be annoying. But I can absolutely sit on my back deck and read a book by them on a cloudy night.
 

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