What is ir?
Infrared (IR) is a part of the electromagnetic spectrum that sits just beyond the red end of visible light. Its wavelengths range from about 700 nanometers to 1 millimeter, so we can’t see it, but we can feel it as warmth. Many everyday devices use IR to send or receive information without wires.
Let's break it down
- Wavelength: Longer than visible light, shorter than microwaves.
- Types: Near‑IR (closest to visible), Mid‑IR, and Far‑IR (closest to microwaves).
- How it works: An IR emitter (like an LED) flashes light; a detector (photodiode or sensor) picks up the pattern and turns it into electrical signals.
- Common forms: IR LEDs, IR lasers, IR cameras, and IR sensors.
Why does it matter?
Because IR can transmit data or detect heat without needing a physical connection, it enables remote controls, night‑vision cameras, thermal imaging, and contactless temperature checks. It’s also safe for most applications since it doesn’t ionize matter like X‑rays.
Where is it used?
- TV and audio remote controls
- Security and night‑vision cameras
- Thermal imaging for building inspections, firefighting, and medical diagnostics
- Smartphone face‑unlock and gesture sensors
- Industrial machine vision and quality control
- Wireless data links in some IoT devices
Good things about it
- Works without line‑of‑sight in many cases (reflected IR can be detected).
- Low power consumption, especially with LEDs.
- Inexpensive components are widely available.
- Safe for humans and most materials.
- Can see heat differences that visible light cannot.
Not-so-good things
- Limited range compared to radio or Wi‑Fi; signals weaken quickly over distance.
- Can be blocked or scattered by certain materials (e.g., glass, water droplets).
- Susceptible to interference from other IR sources like sunlight or heat lamps.
- Lower data rates than higher‑frequency wireless technologies.
- Requires a clear line of sight for many precise applications, such as remote controls.