Safety warning for the "DVD Laser Flashlight Hack"

In August 2007, text and video instructions appeared on the Internet, telling how to "turn a regular MiniMag flashlight into a cool 'burning laser pointer'." The basic idea is to remove the laser from a DVD-burning drive, power it with a commercially available laser diode driver, and insert the assembly into a MiniMag flashlight cell.

The resulting laser is claimed to be 245 mW, which is just about 1/4 of a watt. If this claim is true, the "DVD Laser Flashlight Hack" is about 50 times more powerful than the 5 mW U.S. limit for legal laser pointers.*

Be cautious with high power laser pointers

In the video, the laser is shown lighting a match at a distance of a few feet, and popping a black balloon. As you might expect, a 245 mW beam is definitely dangerous, primarily to the eyes.

For most people, we do not recommend that you build this unless you really know what you are doing. For example, this would not be an appropriate science project for most schoolchildren.

These hazards include the following:

• SEVERE EYE HAZARD  A visible beam of this power could cause instant, permanent damage to the retina, literally quicker than "the blink of an eye". Therefore
       -- Do NOT aim the beam at any living thing.
       -- Especially, NEVER aim the beam in or near anyone's eyes.
       -- Do NOT aim the beam on or near reflecting surfaces, when you don't know where the reflected beam could go. A reflected beam can be just as dangerous as the direct beam.
       -- Do NOT aim the beam when you don't know whether there is a person at or near the other end. Always be able to see the beam endpoint.

• SKIN HAZARD  The beam also can cause skin burns. If the beam does stay on your skin, it causes a small, painful burn similar to hot wax.

• POSSIBLE FIRE HAZARD  A fixed beam on a dark surface could cause smouldering or even fire. (Recall that the video shows the DVD laser lighting a match a few feet away.)

• POSSIBLE INVISIBLE BEAM HAZARD  Some laser diodes emit invisible infrared (heat) beams. These may be in addition to the visible light, or the laser may emit only invisible IR beams. Because you can't see the laser dot or beam to avoid it, an invisible beam can be more of an eye safety hazard than a visible beam.
       Therefore, if you build any kind of do-it-yourself laser device, assume there is a strong, invisible IR beam at first. You can check in a number of ways, including using camcorders which can see the IR from a TV remote (if they see the remote, they probably will see the laser IR beam). You can also use IR-blocking glass, so that only the visible beam comes out.

• POSSIBLE STRONGER-THAN-NORMAL BEAM Laser diodes are tricky. It is all too easy to drive one with so much current that you get a strong beam which lasts only a few seconds or minutes. If you do use too much current, you may also get a stronger-than-normal beam. Therefore, be extra careful until you have finished your project and had a chance to test out the final (hopefully current-stabilized) laser.

Other potential hazards

• POSSIBLE AVIATION HAZARD  Do NOT aim any laser beam at an aircraft in the sky, no matter how far away. Do NOT aim the beam over a heavily-traveled area such as above an airport or takeoff/landing path. Do NOT aim the beam in the sky without first checking that there are no aircraft (no moving lights or moving "stars").
       This is not so much for pilots' eye safety as it is to prevent the more likely hazard of distracting a pilot during critical phases of flight. Much more info on laser-aviation safety is here.

• POSSIBLE THREAT HAZARD  Do NOT aim the laser at people or (especially!) law enforcement in such a way that they may perceive a threat, such as a laser-aimed weapon. There has been at least one case of a person being fatally shot by police, because a laser beam was aimed at them and the person did not stop. Also, a number of people have been prosecuted for aiming laser beams at aircraft.

• ILLEGAL FOR USE IN A LASER SHOW OR DEMONSTRATION  In the U.S. and many other countries, lasers above 5 mW cannot be used in a public demonstration or display, without special permission. This applies whether the demo/show is for profit, or is simply part of another event such as a concert or rave. If you are in the U.S., contact the U.S. FDA Center for Devices and Radiological Health for information on the "variances" (permissions) you will need.

A final warning note

As the video demonstrates, a laser of this power (around 250 mW) is not a toy. While you certainly must keep others safe, you the experimenter may have the largest risk. Most laser eye injuries happen to the laser experimenter or user. And it takes only one stray reflection to cause a permanent blind spot.

If you have any questions about laser safety, feel free to contact us. While everyone at ILDA enjoys using high-powered visible lasers, all of us are also very careful to use them in a safe way, to avoid any injuries to ourselves or others.

*It is possible to buy "laser pointers" with powers greater than 5 mW, but these are not recommended for average, everyday laser pointer use.