Laser circuits

I think everybody saw Laser Effects that shows up stages, discos or festivals. There are two categories on the laser effect. One is Beam Effect, it shows the laser beams that flying in the air to the audience. The other is Screen Effect, it shows the laser graphics that drawn on the screen by a moving laser spot. The first one is preferred better than second. The beam effect is very exciting, so that many Laser Light Shows are also being given. The laser equipments working in the laser light show are called Laser Projector.

As before, there are two sections: the transmitter board and the receiver board, both powered by a separate 9V battery or a fixed voltage power supply, depending on your needs. The transmitter board has an electret microphone module at one end, and the laser diode at the other end. The electronics modulates the intensity of the laser beam according to the output of the microphone. The laser diode has an inbuilt collimating lens, and is simply a module that connects to the transmitter board. The previous design required brackets for the laser diode assembly.

The nitrogen laser will give 100kW pulses of light at 337.1nm (UVA light). The pulses are only 6ns long, so the energy per pulse is just 0.6mJ. It is a very simple laser, and it does not require mirrors or glass working at all! But using a mirror at one end of the laser will boost the output to over 250%. And if the nitrogen entering the laser (it is a flowing gas laser, but it can be made sealed) is cooled, it can go up to 120 pps. So if it is running at 120 pps, and has a mirror at one end, the average power output will be 180 mW. Although the beam is invisible it can be used to pump dye lasers to give beams with wavelengths ranging from infrared to ultraviolet.

Laser based projects used to be expensive, until the development of solid state lasers. This project is designed for the entry level laser experimenter. The circuit allows any two computers with serial (RS-232) communication capability to communicate over 200 meters using a laser beam. A low cost transmitter only circuit is also presented here for use in one way communication and other laser based projects.

Here is the receiver circuit. It uses the OPT210 detector followed by an op-amp. This gives a low level output which is further amplified by an external LM386 audio amp that can drive headphones or a speaker. The detector uses a 0.25 watt leaded 2.2M resistor as feedback. The components around the first 071 op-amp are for a bandpass filter centered on 500Hz. This is usable from 400 to 700 and offers significant attenuation from 50/60Hz sources of interference. Design equations for this circuit are available in the ARRL handbook.

If you have ever worked with lasers, you know how fun and interesting it can be, you also know how expensive it can be. The high voltage power supplies for the laser tubes are often more expensive then the tubes themselves. This supply can be built with commmon parts, most of which you probably already have in your junk box. The secret is the transformer used. It is a common 9V 1A unit, connected backwards for step up.

If you have ever worked with lasers, you know how fun and interesting it can be, you also know how expensive it can be. The high voltage power supplies for the laser tubes are often more expensive then the tubes themselves. This supply can be built with commmon parts, most of which you probably already have in your junk box. The secret is the transformer used. It is a common 9V 1A unit, connected backwards for step up.

This set of two circuits from the basis for a very simple light wave transmitter. A LASER beam is modulated and then aimed at a receiver that demodulates the signal and then presents the information (voice, data, etc..). The whole thing is very easy to build and requires no specialized parts execpt for the LASER itself. LASERs are available from MWK Industries.

This circuit was originally designed to detect weak flashed of laser light bounced off of a fabric video projection screen. It was used as part of a firearm training system. It generates a 100mS output pulse whenever it detects a 3ms to 5ms-laser burst, modulated at 40KHz. It is very sensitive and could be modified for long-range laser communications.

Inexpensive, 16-bit, monolithic DACs can serve almost all applications. However, some applications require unconventional approaches. This Design Idea design concerns circuitry I recently designed for a tunable-diode laser spectrometer for a Mars-exploration application. The control circuitry included two 16-bit DACs that interface to the radiation-hardened, 8051-variant 69RH051A microcontroller.

This is a simple Laser communication system. It can transmit and receive signal from any audio device.Communication distance is few meters. All components are not critical. Transistor 2N2222 may be on the coolrib. Laser diode is from laser pointer.

Some laser tag or simulated combat games can use this circuit to send short bursts of modulated laser light at the opponent's vest, equipped with a matching light receiver. The circuit operates from three 1.5v cells (4.5v) that should provide enough energy for about 200,000 shots.

This circuit uses a large 1cm X 1cm silicon PIN photo diode and a transimpedance amplifier to measure the light power output of infrared and visible LEDs and laser diodes. It can be modified to produce almost any milliwatts to volts scale factor. It can be connected to either a multi-meter or an oscilloscope.

This circuit takes advantage of some new vertical cavity surface emitting lasers (VCSEL) that don’t require light output control circuits. The circuit shows how to drive the device from a single high speed CMOS IC. The circuit can easily be modified to transmit signals from kilohertz to about 50MHz.

This circuit was originally designed to detect laser light pulses for an optical Ethernet communications system. It has good ambient light immu

This circuit uses a crystal and a 4060 oscillator / divider to produce a square wave output in the audio range. In this case a 4MHz crystal giving 488Hz on pin 2. The 5Vp-p square wave is buffered by 3 transistors which includes a totem pole driver. I've used two diodes to reduce the voltage by 1.2V which then supplies the laser module. One switch is attached to the reset pin of the 4060. This is used to select CW ( constant laser output) or Modulated CW. Another switch wired between the key input and ground allows the laser to be keyed via a phono socket or it can be switched permanently on. This is very useful when aligning the beam onto a distant receiver.

The circuit is almost identical to the original receiver. Changes are the new detector / PCB layout and improved op-amps. It uses a single supply at 12 - 13.8V. The detector has a a 10M Ohm feedback resistor soldered directly between pins 2 and 5. The detector output is followed by a NE5534 low noise op-amp (3.4nV/Hz) which is configured as a bandpass filter. The final NE5534 is an inverting buffer amplifier with a gain of 20. The complete detector assembly is designed to be mounted in a small metal box at the focal point of a lens.

When the light head has found the brightest spot, it lights up the high efficiency led at the front. The motor is a 10mA @ 2.5V FTB gear motor, partnr 242551 from conrad The 2466 solar panels are carried by a giant 6A diode just for looks. The circuit is quite well tested by now, you might have trouble finding the 74AC86. (digikey)

This circuit uses a large 1cm X 1cm silicon PIN photo diode and a transimpedance amplifier to measure the light power output of infrared and visible LEDs and laser diodes. It can be modified to produce almost any milliwatts to volts scale factor. It can be connected to either a multi-meter or an oscilloscope.

This circuit was originally designed to detect laser light pulses for an optical Ethernet communications system. It has good ambient light immunity.