Lighting
Why This Matters
Artificial lighting doubles your productive hours. Before electric light, work stopped at sunset or struggled under flickering candles and smoky oil lamps. A single LED running from a car battery produces more useful light than a dozen candles while lasting thousands of hours. Lighting is the first electrical technology that visibly transforms daily life, and it is the easiest to implement.
Pre-Electric Lighting
Before you have a working electrical system, you still need light. These methods bridge the gap.
Oil Lamps
The oldest artificial light source. A container holds liquid fuel, a wick draws the fuel up by capillary action, and the burning wick tip produces light.
Fuels (ranked by light quality):
| Fuel | Smoke | Smell | Brightness | Availability |
|---|---|---|---|---|
| Olive oil | Very low | Mild | Moderate | Mediterranean regions |
| Rendered tallow (animal fat) | Heavy | Strong | Low-moderate | Common wherever there is livestock |
| Fish oil | Heavy | Strong | Moderate | Coastal areas |
| Linseed/flax oil | Low | Mild | Moderate | Agricultural areas |
| Beeswax (melted) | Very low | Pleasant | Good | Beekeeping required |
| Pine resin/pitch | Heavy | Strong | Bright | Coniferous forests |
| Kerosene (if scavenged) | Low | Moderate | Very bright | Fuel storage, gas stations |
Building a simple oil lamp:
- Any heat-resistant container (ceramic cup, tin can, glass jar)
- Wick: twisted cotton cloth, cotton rope, or plant fiber cord
- Fill container with oil
- Lay the wick so one end is submerged in oil, the other extends above the rim
- Light the exposed wick end
Tip
A floating wick produces steadier light. Punch a hole in a small piece of cork or tin. Thread the wick through the hole. Float it on the oil surface. The wick length above the float determines flame size.
Candles
Solid fuel (wax or tallow) with an embedded wick. More portable than oil lamps but more labor to produce.
Tallow candles (basic):
- Render animal fat by melting and straining through cloth
- Cut wicks from cotton string or twisted plant fiber
- Dip the wick repeatedly in melted tallow, letting each layer cool between dips
- 15-20 dips builds a usable candle
- Each candle provides 1-2 hours of light depending on thickness
Beeswax candles (superior): Same dipping process, but beeswax burns cleaner, brighter, and longer. Beeswax candles were luxury items throughout most of history for good reason.
Gas Lighting
Coal gas or acetylene gas burned through a mantle produces very bright white light. This requires gas generation infrastructure (coal gasification or calcium carbide + water for acetylene) and is covered in Industrial Chemistry.
Arc Lamps
The first practical electric light. Two carbon electrodes are brought together, a massive current flows, then the electrodes are separated slightly. The current continues to flow through ionized air in the gap, producing an intensely bright arc.
Building a Carbon Arc Lamp
Materials:
- Two carbon rods (battery cores from zinc-carbon D-cells, or graphite rods)
- A power source capable of high current (10+ amps at 40-60V)
- A ballast resistor or inductor to limit current
- A mounting mechanism that allows adjustable gap between rods
Construction:
Step 1 — Mount two carbon rods in holders that allow vertical adjustment. The rods should point toward each other, tips about 5 mm apart.
Step 2 — Wire a ballast (resistor or iron-core inductor) in series with the arc. Without a ballast, the arc draws unlimited current and destroys the power supply. A length of iron wire or a coil of wire on an iron core works.
Step 3 — Connect power supply to the circuit: one terminal to each rod through the ballast.
Step 4 — Touch the rod tips together briefly, then slowly separate them. The arc should strike and sustain across the gap.
Power supply → Ballast → Carbon rod A ← arc gap → Carbon rod B → Return
Step 5 — Adjust the gap as the carbon tips burn away (erode). The positive rod erodes about twice as fast as the negative.
Warning
Arc lamps are extremely bright — bright enough to cause permanent eye damage. Never look directly at the arc. The ultraviolet radiation can also cause sunburn-like skin damage. Use an arc lamp only where the light can be diffused or reflected, never as a close-range reading light.
Practical uses: Workshop lighting (reflected off ceiling or walls), outdoor area lighting, searchlights. Arc lamps were the first commercial electric lights, used for street lighting in the 1870s-1880s before incandescent bulbs replaced them.
Limitations
- Requires constant gap adjustment as electrodes burn away
- High current demand
- Cannot be easily dimmed
- UV emission
- Carbon rods are consumable
Incandescent Bulbs
An incandescent bulb passes current through a thin filament. The filament’s high resistance causes it to heat until it glows white-hot, producing light. The filament is sealed inside a glass envelope filled with inert gas or vacuum to prevent the filament from burning up in oxygen.
Filament Materials
Edison’s original bulb used carbonized bamboo and lasted over 1,000 hours. You can replicate this.
| Filament Material | How to Make | Expected Life | Brightness |
|---|---|---|---|
| Carbonized bamboo | Heat thin bamboo strips in absence of air until black | 200-1,000 hours | Moderate |
| Carbonized cotton thread | Same process with cotton thread | 40-100 hours | Low-moderate |
| Carbonized cardboard | Same process with thin cardboard strips | 20-50 hours | Low |
| Thin iron wire | Draw or hammer iron wire very thin | 10-50 hours | Low (red glow) |
| Tungsten wire (scavenged) | Extract from old incandescent bulbs | 1,000+ hours | Bright white |
Carbonization process:
- Place your filament material in a sealed metal container (tin can with tight lid)
- Heat in a fire for 30-60 minutes
- The material turns to pure carbon without burning because oxygen cannot reach it
- Carefully remove — carbonized filaments are extremely fragile
Building an Incandescent Bulb
This is one of the most challenging DIY electrical projects, but it is achievable.
Step 1 — Prepare the filament
Carbonize a thin bamboo strip or cotton thread as described above. The filament should be thin enough to have high resistance (glows rather than just getting warm) but thick enough not to break immediately.
Step 2 — Build the glass envelope
You need a glass-blowing capability (see Glassmaking). Blow or form a glass bulb shape with an opening. Two lead-in wires (copper or nickel) must pass through the glass to support and connect the filament.
Step 3 — Mount the filament
Attach the carbonized filament to the two lead-in wires inside the glass bulb. The connections must be firm but gentle — carbon filaments break under the slightest force.
Step 4 — Create a vacuum or fill with inert gas
Vacuum method: Use a hand pump to evacuate air from the bulb through a thin glass tube, then seal the tube with a flame. Even a partial vacuum dramatically extends filament life.
Gas fill: If you can produce nitrogen (by removing oxygen from air using hot iron filings), filling the bulb with nitrogen allows higher filament temperature and brighter light.
Step 5 — Seal and connect
Seal the glass envelope completely. Connect the external lead-in wires to your circuit.
Tip
Rather than building bulbs from scratch, scavenge incandescent bulbs from buildings, cars, flashlights, and appliances. Even dead bulbs can be refilled with new filaments if the glass is intact. Car bulbs (12V) are ideal for battery-powered systems and are designed to handle vibration and temperature extremes.
Tungsten: The Ideal Filament
Tungsten has the highest melting point of any metal (3,422 degrees Celsius). This allows it to run much hotter than carbon, producing more light per watt and a whiter color. Every modern incandescent bulb uses tungsten.
You cannot easily make tungsten wire, but you can salvage it from existing bulbs. Even a broken bulb’s filament can be carefully removed and mounted in a new glass envelope.
Fluorescent Lighting
Fluorescent tubes are far more efficient than incandescent bulbs (60-100 lumens per watt vs 10-17 lumens per watt). They work by passing current through mercury vapor, which emits ultraviolet light. A phosphor coating on the inside of the tube converts the UV to visible white light.
How They Work
- A sealed glass tube contains a small amount of mercury and a low-pressure inert gas (argon)
- Electrodes at each end emit electrons when heated
- Electrons collide with mercury atoms, exciting them
- Excited mercury atoms emit ultraviolet photons
- UV photons hit the phosphor coating on the tube wall
- Phosphor converts UV to visible light
Ballast Requirement
Fluorescent tubes have negative resistance characteristics — once the gas ionizes, current increases without limit. A ballast (inductor or electronic circuit) limits current to prevent the tube from destroying itself.
Magnetic ballast: An iron-core inductor in series with the tube. Heavy and buzzy but simple and durable. Scavenge from any fluorescent light fixture.
Electronic ballast: A circuit that converts power to high-frequency AC (20-50 kHz), which is more efficient and eliminates the hum. More complex but lighter.
Practical advice: Fluorescent tubes are excellent to scavenge but nearly impossible to manufacture from scratch. Collect intact tubes and ballasts. They last 10,000-20,000 hours and produce 4-6 times more light per watt than incandescent bulbs.
LED Lighting
LEDs (Light Emitting Diodes) are the most efficient practical light source available. They convert electricity directly to light at the semiconductor junction level.
How LEDs Work
An LED is a semiconductor device. When current flows through the junction between two types of semiconductor material (P-type and N-type), electrons drop from a higher energy state to a lower one. The energy difference is released as a photon of light.
Key LED characteristics:
- Forward voltage: The minimum voltage needed to turn on the LED (typically 1.8-3.3V depending on color)
- Forward current: The operating current (typically 20 mA for indicator LEDs, 350 mA-1A for power LEDs)
- Polarity: LEDs only conduct in one direction. Reverse polarity blocks current (and can damage the LED at high voltage)
- Color: Determined by the semiconductor materials, not filters
| LED Color | Forward Voltage | Semiconductor |
|---|---|---|
| Red | 1.8-2.2V | Gallium arsenide phosphide |
| Yellow | 2.0-2.4V | Gallium arsenide phosphide |
| Green | 2.0-3.0V | Gallium phosphide |
| Blue | 3.0-3.5V | Gallium nitride |
| White | 3.0-3.5V | Blue LED + phosphor coating |
Practical LED Use
LEDs are abundant in the pre-collapse world: flashlights, car lights, holiday string lights, household bulbs, traffic signals, screens, indicators on every electronic device.
Wiring LEDs to a 12V battery:
Every LED needs a current-limiting resistor in series. Without it, the LED draws excessive current and burns out instantly.
R = (V_supply - V_forward) / I_forward
For a white LED (3.2V, 20mA) on 12V:
R = (12 - 3.2) / 0.02 = 440 ohms
Use the nearest standard value: 470 ohms
Power in resistor: (8.8V x 0.02A) = 0.18W → quarter-watt resistor is fine
Wiring multiple LEDs:
- Series: Add forward voltages. Three white LEDs in series = 9.6V. Resistor: (12 - 9.6) / 0.02 = 120 ohms. More efficient because less voltage is wasted in the resistor.
- Parallel: Each LED needs its own resistor. Same resistor calculation as a single LED. Less efficient but if one LED fails, the others stay on.
Tip
For maximum efficiency, wire LEDs in series strings that use as much of the supply voltage as possible. On a 12V supply, three white LEDs in series (9.6V) wastes only 2.4V in the resistor. One LED alone wastes 8.8V in the resistor — 73% of your power becomes heat.
Scavenging LEDs
Best sources:
- LED household bulbs (contain multiple high-power LEDs on a circuit board)
- Car LED headlights and taillights
- LED flashlights
- LED string lights (holiday lights)
- LED strip lights (adhesive-backed flexible strips)
- Traffic signal LED modules
LED strip lights are particularly useful. They come in 12V rolls with resistors already built in. Cut at marked intervals, connect to a 12V battery, and you have instant lighting. Scavenge every roll you find.
Fixture Wiring
Basic Switch Wiring
A light fixture needs a switch. Wire the switch on the hot (positive) wire, never on the neutral (negative/return). This ensures the fixture is de-energized when the switch is off.
DC system:
(+) ──── Switch ──── Light ──── (-)
AC system:
Hot ──── Switch ──── Light ──── Neutral
Three-Way Switching
To control one light from two locations (top and bottom of stairs, both ends of a hallway), use two three-way switches.
A three-way switch has three terminals: one common and two travelers. The travelers connect the two switches. The common on one switch connects to hot, the common on the other connects to the light.
Hot ── Common [SW1] ── Traveler A ── [SW2] Common ── Light ── Neutral
── Traveler B ──
Either switch can turn the light on or off regardless of the other switch’s position.
Building a Lamp Socket
For scavenged bulbs with standard Edison bases (screw-in):
- Find or form a metal cylinder that the bulb base threads into
- Place an insulated contact point at the bottom of the socket (center contact)
- Connect one wire to the center contact, the other to the threaded shell
- Mount the socket securely — bulbs get hot
For 12V car bulbs: Use the original car bulb socket if possible. Otherwise, solder or bolt wires directly to the bulb contacts. Car bulbs with bayonet bases (push-twist) can be held in simple spring-clip holders.
Light Output Comparison
How much light does each source actually produce? The comparison is dramatic.
| Light Source | Power Input | Light Output (lumens) | Efficiency (lm/W) | Lifespan |
|---|---|---|---|---|
| Candle | ~80W (chemical) | 12 | 0.15 | 1-2 hours |
| Oil lamp | ~40W (chemical) | 20-40 | 0.5-1.0 | Fuel-dependent |
| Carbon arc lamp | 200-500W | 2,000-10,000 | 10-20 | Rod replacement needed |
| Incandescent (carbon filament) | 60W | 600 | 10 | 200-1,000 hours |
| Incandescent (tungsten) | 60W | 850 | 14 | 1,000-2,000 hours |
| Fluorescent tube | 30W | 2,400 | 80 | 10,000-20,000 hours |
| LED (modern) | 10W | 800-1,000 | 80-100 | 25,000-50,000 hours |
The takeaway: A 10-watt LED produces as much useful light as a 60-watt incandescent bulb, six times more than a candle, and lasts 25 times longer. If you have any LEDs and a battery, use them first.
Important
Prioritize scavenging LEDs above all other light sources. A single LED household bulb (10W, 800 lumens) running from a 12V battery for 4 hours per night uses only 40 watt-hours — achievable with a small solar panel or a few minutes of generator run time. One LED bulb replaces 70 candles worth of light.
Practical Lighting Design
Light Levels by Activity
Not every space needs the same amount of light. Over-lighting wastes power.
| Activity | Minimum Light Level | Example Setup (12V LEDs) |
|---|---|---|
| Hallways, passages | Low (50 lux) | One 3W LED strip per 3 meters |
| Living areas, dining | Moderate (150 lux) | Two 5W LED bulbs per room |
| Reading, cooking | High (300 lux) | Directed 10W LED task light |
| Workshop, detailed work | Very high (500+ lux) | Multiple 10W LEDs, overhead + task |
| Sleeping areas | Minimal | One dim LED nightlight (under 1W) |
Workshop Lighting Layout
A workshop needs even, shadow-free illumination for safe tool use.
Principles:
- Overhead general lighting — mount LED panels or strips on the ceiling, spaced evenly. Aim for uniform coverage with no dark spots.
- Task lighting — adjustable LED lamps aimed at workbenches, lathes, drill presses. Position to illuminate the work without casting shadows from your hands.
- No single-point illumination — if one light fails, you should still be able to see well enough to work safely.
Recommended workshop setup (5m x 5m):
- Four 10W LED panels mounted at ceiling level, one in each quadrant
- Two adjustable 5W task lights at the primary workbenches
- Total: 50W, approximately 4,000-5,000 lumens
- Battery draw on 12V: about 4.2A
Homes and Community Spaces
Efficiency strategy:
- Use the smallest number of lumens needed for each space
- Put switches on every fixture — lights off in unoccupied rooms
- Use reflective surfaces (whitewashed walls, tin reflectors) to maximize light distribution
- Position lights high for general illumination, low for task lighting
Tip
A simple tin reflector behind a bare LED triples the useful light in one direction. Cut a piece of tin can, polish one side, and curve it behind the LED. The reflector directs light that would otherwise go into the wall or ceiling into the room where you need it.
What’s Next
With lighting established, you can extend electrical infrastructure to more advanced applications:
- Telegraph — electrical signals over wire for long-distance communication
- Semiconductors — the technology behind LEDs leads to transistors and computing
- Electrochemistry — use electricity for metal refining and chemical production
Lighting — At a Glance
Priority order for light sources:
- Scavenged LED bulbs/strips (80-100 lm/W, 25,000+ hours)
- Scavenged fluorescent tubes with ballasts (80 lm/W, 10,000+ hours)
- Scavenged incandescent bulbs (14 lm/W, 1,000 hours)
- DIY carbon-filament bulbs (10 lm/W, 200-1,000 hours)
- Oil lamps and candles (last resort)
LED wiring formula: R = (V_supply - V_forward) / I_forward
Efficiency tip: Wire LEDs in series to minimize resistor waste. Three white LEDs in series on 12V wastes only 20% in the resistor. One LED alone wastes 73%.
Source One evening (4h) energy cost Equivalent candles 10W LED bulb 40 Wh 70 candles 60W incandescent 240 Wh 70 candles Candle 320 Wh (chemical) 1 candle Workshop standard: 50W of LED lighting for a 25 m² shop gives professional-grade illumination.
Scavenging priority: LED strip lights (12V, pre-wired), LED household bulbs, car LED assemblies, flashlight LEDs. Grab every one you find.