The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

LED Beam Patterns

Red LED Beam Pattern
Red LED Beam Pattern

For some reason, everybody thinks LEDs put out nice Gaussian beams. Unless the specs say so, it just ain’t so. Some pix from the Trinity Robotics Contest show the situation.

This is the table used in the RobotWaiter contest. It has a visible red LED on each face to aid in locating and aligning, but you better not depend on the actual beam intensity as a function of angle!

The same picture in pure IR shows the situation with a bit more contrast. Although it’s a visible red LED and I have a visible-cut filter on the lens, there’s enough energy for an image.

Red LED Beam Pattern in IR
Red LED Beam Pattern in IR

These IR LEDs have the same general pattern.

IR Distance Sensor Emitters
IR Distance Sensor Emitters

Pix with my ancient Sony DSC-F717 in NightShot mode with a Hoya R72 IR filter.

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  1. Red Laser vs. IR LED Photosensor | The Smell of Molten Projects in the Morning Avatar
    Red Laser vs. IR LED Photosensor | The Smell of Molten Projects in the Morning

    […] peak sensitivity to slightly shorter wavelengths than they emit. Aiming a red laser at an ordinary IR LED about a foot away generates 800 mV of […]