How to Make a LED Into a Laser Pointer How to Make a LED Into a Laser Pointer A light-emitting diode (LED) and a semiconductor laser both generate light in the interface region between two different types of semiconductor materials. The energy of the light for both LEDs and lasers is determined by the composition of the semiconductor. The LED and laser emit light in a relatively narrow range of wavelengths. However, lasers put all their energy in a single wavelength, which emits from a tiny spot. LEDs spread the energy over more wavelengths and send that light from a larger spot into wide cone. Instructions 1 Select a LED wavelength near the peak of the visual response of the eye. The human eye is not equally sensitive to all wavelengths, as the eye peaks at a yellowish-green wavelength of about 560 nm (billionths of a meter). A LED near that wavelength region will create a brighter spot. 2 Find an LED in the desired wavelength with at least a few milliwatts of output power, say three or more. Read the specification sheet and find the electrical requirements, in particular the forward voltage, and the operating current. For example, a typical LED might have an operating current of 20 mA and a forward voltage of 2 V. 3.Select a watch battery or batteries to supply the needed voltage. For example, use a lithium cell with a voltage of 3 volts. 4 The right resistor keeps the LED safe from damage from too much current. Calculate the size of a current limiting resistor. The right resistor is given by the equation: R = (supply voltage - LED forward voltage) / (operating current). In the example, R = (3 - 2) / .020 = 50 ohms. 5 Calculate the diameter of the lens---something that fits within the diameter of the holder. Select a focal length equal to the diameter of the lens. Because the LED spreads light in a wide angle, to capture as much light as possible the lens should have the shortest realistic focal length---which is equal to the diameter of the lens. A reasonable diameter for a pointer would be one half inch, so the lens could be a 10 mm diameter/10 mm focal length lens. 6 Wire the LED circuit, connecting the LED with the resistor and battery through the switch. 7 Place the assembled circuit in the holder, bonding, crimping or soldering the LED in place. 8 Put the lens in the barrel and adjust the position to create the smallest spot at the desired distance. Bond the lens with epoxy or RTV. dm8000 hd wholesale led light usb flash drive usb flash drive wholesale usb flash drive flash drive manufacturer led lighting LED Wall Wash light LED video pixels LED Digital Tube light LED Spot Light LED Point Light LED Under-ground Lighting LED Commerical Lighting LED ba?ador de pared LED píxel de luz Tubos LED luz llevada del punto LED punto de Luz lenovo cellphone LED Spotlights Buried LED Iluminación Comercial ????? ????? ??? ????? ???????????? ????? ???????? ???????????? ?????? Power supply for DM500C DM500S DM500T Remote control for DM600PVR DM7000 DM7020S DM7025 Power Supply for DM600PVR DM7000 DM7020S DM7025 dm8000 hd dreambox dm8000 dm 8000 hd dreambox 8000 dreambox dm7020 dm7020 HD dreambox 7020 dm7020 HD dreambox 7020 Dreambox dm800 HD Se dm800 hd se with Wifi dm800 hd pvr dreambox dm800 hd pvr cheap dreambox dm800 hd pvr http://www.dreamboxok.com/dm500si.html Dreambox dm500S satellite receiver http://www.dreamboxok.com/Dreambox-DM-500-S.html DreamboxDM 500 OEM http://www.dreamboxok.com/DM500-OEM.htm Dreambox DM500C http://www.dreamboxok.com/Dreambox-DM-500-C.html Dreambox DM500C OEM http://www.dreamboxok.com/dm500c-oem.html Dreambox DM500S OEM http://www.dreamboxok.com/dm500s-oem.html Dreambox DM500Si Silver http://www.dreamboxs.com/dm500si.htm Dreambox dm500Si black http://www.dreamboxok.com/dm500si-black.htm Dreambox dm 518S http://www.dreamboxs.com/dreambox-dm518s.html Dreambox DM500T http://www.dreamboxok.com/Dreambox-DM-500-T.html AzBox HD Elite
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