The introductory post on this project mentioned most of the high level considerations for safety and compliance when shooting a laser into the sky. Here, we will go into the gory details.
When lasers will be operated outdoors in the U.S., the Federal Aviation Administration must be given the opportunity to review the safety of the proposed laser operation at least 30 days in advance. Laser beams can potentially affect air traffic and distract or impair pilots during flight, so to mitigate this risk, the FAA reviews the details of the planned operation and responds with a letter of objection or non-objection. The details for how and why to provide this information to the FAA can be found in the Advisory Circular 70-1, with the attached forms “Notice of Proposed Outdoor Laser Operation(s)” and “Laser Configuration Worksheet.” Note that if the laser operations are for entertainment as opposed to scientific use, the Food and Drug Administration must be notified in addition to the FAA.
Beyond the basic information such as date and time of operation, site latitude, longitude, and elevation, etc., it is necessary to calculate and provide energy density values at various distances from the laser’s origin. Every laser diverges to some extent, so that its beam spreads out and becomes less bright over distance. The divergence of a laser is measured in milliradians, which is an angle measurement (1° ≈ 17.45 mrad). The amount of energy in the laser beam stays relatively constant over distance, so as it diverges, the density of the energy decreases. In other words, the amount of energy per unit of area in the cross section of the beam decreases as you take cross sections farther and farther from the laser’s point of origin.
Read more, cool to see there are ways to do cool stuff and work within reasonable rules.
8-6-2021 (August 6, 2021) is the Snakiest day of the year and it’s also this year’s CircuitPython Day! The day highlights all things CircuitPython and Python on Hardware. See you there!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.