Designing and Building a Tiny House, and Everything In Between. 

Ribbons, Sails 

& Dandelion Fluff

May 2020 –

Building a Shelter

Steel Frames & Cladding

Apr 20 – Jul 19

Doors & Windows

The Beginnings of a ‘Tiny’ Project

Apr 19 – Aug 17

Succulents & Raspberries;

A First Foray into Gardening.

Oct 17 – Apr 15

electricity

After finally getting stuck into some building I returned to my lighting research with renewed energy. Inspired to tackle my work with a slightly more hands-on approach I pulled out a couple of light bulbs from our hallway cupboard to have a look for myself. Funnily enough, the cardboard boxes proved the more interesting and soon I was reading the information the manufacturers consider major selling points.

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What is a watt?

Watts measure the energy consumed by a bulb.
During the dominance of incandescent’s, watts would be advertised as the measurement of brightness, yet when new lighting technologies were introduced this could no longer be a sound gauge for consumers. This is because halogens and LEDs use less wattage to create the same amount of brightness. For example; a 100-watt incandescent bulb provides 1600 lumens, whilst you only need a 22 watt LED to achieve the same result. If you used a 100 watt LED, you would be looking at an outdoor floodlight!

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Flipping the box over I found a table detailing the specifications of the globe- voltage, frequency, colour, and output. I break down each one below:

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What is voltage?

Voltage measures the pressure of an electric current.
It is suggested to think of voltage through the terms of water tanks. The water stored in the tank is the charge. The pressure of a connected hose represents voltage. The more water in the tank (battery), the higher the pressure (voltage). As the tank is drained the pressure decreases, just like a torch dims as the batteries run low.

Mathematically, a volt is the amount of joules per coulomb.
Or in English, the amount of work per group of flowing electrons.

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In the case of my lightbulb, the voltage is 240V. As mentioned here, electricity enters your home at 240 volts. When the lightbulb is connected to the home’s circuit (240v) it should deliver the advertised lumens. If you connect this bulb to a lower voltage it will continue to work but will be dimmer than advertised. If you use a bulb recommended for a lower voltage, the light produced will be brighter, but the globe will have a shorter lifespan.

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What is frequency?

This is the invisible flickering of a light bulb connected to AC- it is the pulse of the electricity pumping through the bulb. A frequency of 50/60 cannot be detected by the naked eye. However, if a frequency is too low the eye will detect the flickering which can cause headaches and eye strain. To be honest I don’t really understand the role frequency plays, but for now, that explanation will do.

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What is colour temperature?

Colour temperature is exactly as it sounds, the colour of the light. It is measured in Kelvins. The higher the Kelvin (K) rating, the whiter the light will be. 1000- 3500k produces warm light, 3500- 4100k is neutral, 5000k up is considered cool. This scale remains the same for all lightbulbs.

  • 1900k is candlelight
  • 2000k or under will give a dim soft glow- good for ambient lighting.
  • 2000 to 3000k is best for living rooms and bedrooms as they give a soft white glow.
  • 3100 to 4500k for kitchens/workspaces, good for task lighting. (Bright bluish daylight too harsh for home ambient lighting.)
  • 4800k direct sunlight.
  • 6000k cloudy sky.

My lightbulb has a temperature of 2800k, meaning it produces a soft white light.

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What are lumens?

Lumens is the measurement used to represent how bright a light is. It indicates the total light emitted, no matter the direction. 
Lux is the unit used to measure the output of light in a given area, so 1 lux = 1 lumen metre squared. It is a measurement of the amount of visible light and intensity of the illumination. The centre of a lamp beam is where the light intensity is the highest.

Lumens and lux come into play when planning the lighting of your home when considering Ambient and Task lighting.

Ambient lighting should radiate a comfortable level of brightness and is considered the room’s ‘natural light.’ This is generally achieved through the use of omni-directional (light in all directions) lamps. Downlights will pool light on surfaces so should only be used for task lighting. They are not successful at achieving general illumination. Up to six downlights s would be needed to achieve the same result of an omni-directional light. Light shades can absorb almost half of your light so choose carefully.

Task lighting provides concentrated light for an area of work or reading. It has to be brighter than the ambient lighting to ensure contrast. Lamps and track lighting can be used if the direction needs to be changed. Under counter kitchen lights are used as fixed directional lighting. Task lighting needs to be free of glare and shadows, but bright enough to avoid eye strain.

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Lighting completes the trio of topics I did not want to think too much about, but unlike plumbing and electricity, I’ve found it difficult to kindle any particular enthusiasm for it. After a handful of false starts, I have decided that I need to cut to the chase with this one, to the one aspect that has perked any interest: Radial Circuits. It came to my attention by means of one very helpful and well-informed John Ward. (Here is his YouTube channel for all sorts of electrical explorations). I did grudgingly dedicate a Google-search session to the humble lightbulb itself. So before we get to the fun, here is the hum-drum.

Incandescent Lightbulbs

The role of the lightbulb is to convert energy into light energy. The traditional light bulb, or rather an Incandescent lightbulb, was the first of its kind and it hasn’t changed greatly since it was invented in the late 1800’s.
The glass bulb is capped with a metal base. This base has two metal contact points which connect to the tungsten filament (a very thin coil of metal wire with an incredibly high melting point). When the light bulb is connected to an electrical current, the electrons in the copper collide into the atoms in the filament causing them to vibrate. This vibration heats the atoms to approximately 2000+ degrees Celsius, causing them to glow and thus giving us light. The filament is sealed in a glass bulb to keep oxygen away from the wire as without this seal, the tungsten would burn up within a couple of minutes. 

[This video captures the mesmerising manufacturing process. Seriously, treat yourself. It is super satisfying].

Though immensely popular, incandescent light bulbs are incredibly inefficient; approximately 90% of the energy consumed by the incandescent bulb is used to heat the filament alone. That means only 10% is used to create light, the sole purpose of a lightbulb in the first place. This considerable flaw has seen the development of a number of other light bulb designs, each with the goal of higher efficiency.

Halogen globes

These are very similar to Incandescents except that the bulbs are filled with the gas Hydrogen Bromide. This gas captures and returns any stray, evaporated tungsten atoms, prolonging the life of the filament. It also keeps the glass clear.

Fluorescents

 Glass tubes are filled with gas and capped at each end with an electrode (electrical conductor). When connected to an electric current, electrons knock into the mercury atoms in the gas. This excites them into emitting both visible and ultraviolet light. The insides of the tubes are coated white so that the ultraviolet light can be absorbed and remitted as visible light. This also prevents us from being exposed to UV rays.

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Light Emitting Diodes (LED)

Before we launch into LEDs I will note that I spent far too long researching diodes and how they work, especially considering I had set out to avoid longwinded research into lighting in the first place. Worse, I still don’t believe I truly understand how they work- despite struggling through numerous long-winded YouTube videos. That said, I need proof that I did something with my morning, so I have included it anyway. Please feel free to skip the next three paragraphs because to accept the diode as a light emitting chip is most likely more than sufficient.

A diode is a semiconducting electronic device that has two terminals, one negatively charged (cathode), the other positively charged (anode). It has low resistance in one direction, and high resistance in the other, meaning it will only allow electricity to flow in the one direction.

Semiconductors are materials that are typically insulators; meaning they don’t encourage the flow of electricity. They can, however, be turned into conductors through a chemical process called doping. Extra element atoms can be added to a semiconductor material like Silicon, giving it additional electrons. Materials altered in such a way are known as N-type (negative type) and carry a negative electric charge.
Similarly, you can add atoms which take away electrons, leaving ‘holes.’ When this occurs, the material becomes P-Type (positive type.) These holes carry a positive electric charge. Diodes are created when an N-Type and a P-Type are paired together. 

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The border between the P-Type and N-Type is known as the P-N junction and it is this that keeps the two sides separate. Without an electrical charge, only the electrons and the holes in the center can recombine. This creates a depletion zone where there are no free carriers. It also creates an electrical field. Only when the diode is connected to a battery voltage higher than the electric field can the N-Type electrons gain enough energy to cross the junction. This shrinks the depletion zone and allows the electrons to fill the holes of the P-Type, creating light (photons). The key thing to note is that the battery must be connected negative to negative/positive to positive, otherwise the depletion zone grows larger and there will be no light. 
(sigh)

In conclusion, diodes in LEDs create light. They are an incredibly efficient way of doing so, using only 10% of the energy used to illuminate an incandescent bulb.  The diode itself only amounts to a very small semiconductor chip, known as the ‘die’. These can be cased inside tiny bulbs or mounted directly onto surfaces.

What are the different LED chips available?

LED DIP (Dual In Line): This is the traditional LED light with a tiny bulb (capsule shape top). The hard plastic (epoxy) cap encases a DIP chip and has two parallel connecting pins which act as the anode (longer leg) and cathode. They produce approximately 4 lumens per LED.

Surface Mount LEDs: Smaller and more efficient than the Dual In Lines, SMD’s can produce 50 to 100 lumens per watt. The chips are welded onto circuit boards and used across numerous applications (lamps/signage/car lights/computer monitors). SMD chips can have more than two contact points and up to 3 diodes, each with an individual circuit. This means a red, blue and green diode can be used, allowing the creation of almost any colour.

Chip on Board LEDs: COB’s are the newest application of LED chips and allow for 9 diodes or more. They cannot change colour like SMDs but can produce more lumens with less energy so are used for floodlights. It produces a minimum of 80 lumens per watt.

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Evidently, discussion of watts and lumens demands a post of their own, but for today I am so very done. Plus, Harry and Meghan’s wedding is about to screen! Priorities!

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