LucidScience News for April 28

To see the latest newsletter, click here .

 

Greetings. Gather and decode data for your covert spy operations.

New projects include: 

• Phone number decoder 
• GPS tracking device
• GPS data receiver  

Hope to see you in the builders forum. 

 Cheers, friends.
 
         

Spammer Jammer DIY Electronics Project

A loud and annoying alarm that will make telemarketers think twice about calling back! 

This little box will give those pesky telemarketers an earful of fun! Why it is still legal for telemarketers to invade a person's privacy baffles my mind! Here I am either trying to relax during dinner or busy with a soldering iron on a 144 pin FPGA and then right at the worst moment possible...rrrrrring! So, I drop whatever I was doing to go get the call and to my absolute disgust, it's another spammer trying to sell me some useless product, or worse - an automated message telling me to "Hold on for an important message." Can you imagine the nerve??! They so blatantly destroy MY peace and quiet to put ME on hold as if MY time is not nearly as important as the cheesy redirect they are about to spew into my already angry ears! Oh, did I mention that of all things in this life that I find annoying, phone spammers top my list? This simple project will give those tele-spammers exactly what they are trying to give you - an earful of useless and highly annoying noise. "You're mean, they are just doing their jobs." Well, let me tell ya buddy, they can do some other job that doesn't involve ticking me off otherwise they will become victims to whatever I decide to feed into my own phone line back at them! If you are like me and have no mercy for those who choose to invade your privacy, then this little box will be right up your alley as it sends a very loud warbling alarm sound back into your phone lines, giving the spammer an earful they won't forget. You can even adjust the tone quality from a steady police like siren to a belching screech that sounds like a robotic cat fight. Even though the spammers will probably continue to call you back regardless of being on those useless "Do Not Call" lists, you will at least have some enjoyment at their expense with this device. Figure 1 - This standard phone cord has an RJ11 connector at one end This device can be made in two versions: one that jacks right into your home phone line for maximum volume level, and a portable unit that just feeds sound into the mouthpiece of any portable phone. The wired version is certainly the most effective version as it can deliver the sound to the spammer at a level you could not achieve by screaming into your phone. Because the Spammer Jammer feeds the audio signal directly into the phone line, it bypasses all audio conditioning circuitry in your phone handset and spews out the sound at the maximum volume possible. Having a direct phone line connection also means that it works on every phone in the house connected to that line. If you are not afraid of the "Phone Police", then you can hack into your phone line by simply cutting the end of any standard phone cable that includes an RJ11 connector at one end. This four conductor connector will be used to connect the Spammer Jammer into the phone line, so you need the RJ11 male jack at one end and bare wires at the other end. << Read more about this and other DIY electronics projects >>

Telephone voice changer - DIY project

Change your voice over the phone in real time using a computer or digital processor. 

 

This black box allows routing effects through your phone system

This project converts an old desktop telephone into a versatile audio mixing station that lets you route your telephone calls through an effects processor in order to create a state of the art voice changer. By using a real time computer voice filter or a professional quality effect box, you can change your voice in ways that will make you sound like a completely different person. You can make a man sound like a woman, or a girl sound like a man, or a man sound like an elderly lady, or any possible combination imaginable with results that will fool anyone.

Unlike those "spy toy" voice changers that make you sound like a funny cartoon, a real vocal effects unit or computer vocal filter will alter a voice in a perfectly convincing manner, allowing fine control over both the formant (gender) and the pitch of your voice. Sure, you can have a lot of fun with evil and chipmunk voices as well, but if you really want to mask your voice identity in a convincing manner then this useful device will allow you to connect any microphone compatible audio processing unit into your phone so you can alter your voice in real time. 

There are many extremely powerful audio processing programs available for a computer that allow a person to alter his or her voice by talking into a microphone. Many of them are inexpensive or even free. Music stores also offer digital effect boxes that are designed for vocal processing, and these have the same functionality as the computer programs, but do their processing in a dedicated DSP (digital signal processor). I will be using both the computer software voice changer as well as the "effect box" version of the vocal processor to show how each one can be connected to the phone system using this project.

<<  Read more about this and other DIY electronics projects >>

Motion Activated Camera

A motion activation system that will control the digital camera shutter release button.

This rig will take a photo anytime it senses motion or heat changes

This project uses a heat sensing motion detector to trigger the shutter release button on a hacked digital camera so that high resolution images can be captured anytime a person or animal crosses in front of the motion sensing zone. By hacking into an old motion activated floodlight, the cost is kept to a minimal and based on a pre-existing system that is known to work well. This project converts the motion sensor for DC battery operation, allowing it to become portable and safe from high voltages.

This project also makes use of a circuit from a previous project called "Camera Trigger Hack", which is a pair of relays and drivers fed into the shutter release switch on a digital camera in order to mimic the original functionality of the switch. You could probably feed the output from this circuit directly into the camera shutter switch, but to be safe, the relay adds a level of isolation from the camera circuit board. Some cameras also have an external remote control jack. This could also be used.

Figure 1 - Any common outdoor motion sensor light can be used for this project

Motion sensing lights like the one shown in Figure 1 use a special heat sensor to detect movement of warm bodied creatures. This sensor detects the body heat of the subject as it passes across a pair of small sensing elements inside the heat sensor. This heat sensor is also known as a PIR (Passive InfraRed) sensor and is the magic behind every one of those inexpensive outdoor security lights as well as most indoor motion sensing units. 

Because these devices are mass manufactured, they are easy to find as surplus or even new for very low cost. Many security lights are tossed out when the plastic degrades or when the relay that controls the AC lights fail, so you can probably salvage the needed parts even from one that is deemed to be non functional. 

<< Read more about this and other DIY electronics projects >>

Sound Activated Camera - DIY electronics project

A sound activation circuit that will control the digital camera shutter release button.

Figure 1 - This is the relay interface that controls the camera shutter switch

The small board shown in the left of Figure 1 is a previous project called "Camera Trigger Hack", and it allows any electronic device to issue a focus and shoot command to the camera. I call this a hack because it requires removal of the original switch from the camera in order to hack into the two functions that control the focus and shoot signals on the cameras circuit board.

You "may" be able to build this project without the previous project as long as your camera board will accept the 5 volt digital signals from the 74121 one-shot into the cameras board, but to be safe, this previous project adds a level of safety to ensure your camera will not be damaged by any external device or voltages.

The small circuit board shown in the right of Figure 1 is the board that will be presented here, and it consists of a small microphone, an op-amp preamplifier (LM358), and a digital one-shot switch (74121), which controls the pulse time to the relay board that will trigger the shutter release switch. The one-shot is needed as the camera expects the shutter release to be pressed down by a human, and the pulses sent from the microphone preamplifier will be much too short to be taken seriously by the camera. The one-shot takes this millisecond input pulse and then sends out a digital pulse for a duration that is long enough for the camera to respond.

<< Read more about this and other DIY electronics projects  >>

Repeating Camera Timer - DIY electronics project

An adjustable timer that will continually focus and shoot images on a digital camera.   

      

This system will focus and shoot a photo at some repeating interval This project will extend the "Hacked Camera Trigger" project, allowing a timer to control both the focus and shutter release functions on a digital camera at an adjustable rate. This method of repeating time delayed image taking is also referred to as a "time lapse photography", and can be used to speed up time by piecing together hundreds of photos taken over the span of hours or even days. By first focusing the camera before the shot, the camera will be able to acquire moving targets with far fewer missed or blurry exposures. In this project, a timer feeds a 10 stage counter, allowing up to 10 individual control points, although only two are needed in order to control the camera relay interface. By using the other eight digital output pins on the decade counter, several more cameras can be controlled, or more relays can be added to allow the controlling of various other electrical devices such as solenoids, alarms, lights, or even AC operated appliances. The rate of photo taking can be controlled by a variable resistor, and by altering the value of the timer capacitor, rates of several photos per second all the way down to single photos every hour can be set. This project assumes that you have previously built the "Hacked Camera Trigger" project, although you could certainly interface it to some other hardware as well. Figure 1 - This is the relay interface that controls the camera shutter switch The small board shown in Figure 1 is a previous project called "Camera Trigger Hack", and it allows any electronic device to issue a focus and shoot command to the camera. I call this a hack because it requires removal of the original switch from the camera in order to hack into the two functions that control the focus and shoot signals on the cameras circuit board. You "may" be able to build this project without the previous project as long as your camera board will accept the 5 volt digital signals from the 4017 decade counter into the cameras board, but to be safe, this previous project adds a level of safety to ensure your camera will not be damaged by any external device or voltages.

<< Read more on this and other DIY electronics projects  >>

 

Invisible Light Basics DIY tutorial

An introduction into using infrared radiation to create stealthy night vision spy gadgets 

Infrared radiation can illuminate a scene for night vision operations Night vision is one of the most important factors when considering any kind of video operated spy gadget as this technology allows the viewer to see in complete darkness while the subject is completely unaware. Because infrared light (radiation) falls just below red on the visible light spectrum, making up the wavelengths from about 750 nanometers to about 1500 nanometers, this light cannot be seen by human eyes, but it can easily be seen by many video cameras, making it useful as a covert lighting method in night vision systems. A common example of infrared light is the medium for communication between your remote control and television set. The LED on the end of your remote sends out pulses of infrared light which is received by the infrared detector on the TV and demodulated back into data. Of course, you cannot see the pulses because they are out of our visual range, but the infrared receiver in the television can see the pulses perfectly. Security cameras and mini spy cams can also see infrared radiation very well. They are easy to connect, inexpensive and can be easily hidden. There are many good quality security cameras available on the market that include a low lux video camera in a weather proof housing along with an array of infrared LEDs for night vision applications. Black and white security cameras and small board cameras are particularly sensitive to infrared light. These ultra low lux cameras can usually be purchased for about $100 or less, especially from online sellers. Add 10 or more infrared LEDs, and you now have a night vision system that is better than those that sold for thousands of dollars in the 1980s. Figure 1 - The light spectrum, showing the small segment we call visible light The light spectrum shown in lower half of Figure 1 covers light from ultraviolet right to infrared and shows the small portion of the light spectrum that can be seen by human eyes. Light is visible to our eyes from approximately 400 nanometers (violet) to approximately 700 nanometers (red), and has green (550 nanometers) at the midpoint. What is interesting is that the imaging system in a video camera can see the light extending past both ends of the visible light scale, which includes both infrared and ultraviolet. Since the infrared portion of the light spectrum is not visible to our eyes, the correct term for this portion of the spectrum is infrared radiation, not infrared light, but often both terms are used. The infrared portion of the light spectrum that can be seen by most video cameras covers the range of 700 nanometers well into 1500 nanometers, with exceptional sensitivity around 800 nanometers. Video cameras can also see ultraviolet radiation, but infrared radiation is easier to generate and at higher output levels will not cause any biological dangers like ultraviolet will. Not all video cameras will be able to see infrared light though, especially those designed for high quality color imaging. Camcorders and digital still cameras contain a glass filter that essentially blocks out all infrared light, leaving only the visible portion of the light spectrum so that the image quality is maintained. For this reason, camcorders will not be able to see the infrared light form an illumination system unless you are willing to open up the case and remove the tiny glass filter that has been affixed to the CCD imager. << Read more about this tutorial and other tutorials >>

Camera Trigger Hack

This external controller allows any device to control the shutter release There are times when you need to acquire a very high resolution image, triggered by some external event such as movement, time, or computer control. Video security cameras are very limited in resolution, often to less than 640 x 480 pixels, which in digital camera terms is less than half of one megapixel. Nowadays, a small digital camera that can take an image with a resolution of 4000 x 3000 pixels can be purchased for mere pocket change, so even if your subject is a long distance from the camera, the details will still be present in the image when zoomed on a computer screen. This simple project demonstrates how to hack into the camera's shutter release button to add some kind of external control to allow automated picture taking. Because this project is a hardware hack, you should not try this with a good camera, or one that you are worried about breaking. There is always a possibility of destruction when cracking the case open on such a small electronic device that is jammed full of tiny components. Of course, if you are good with small tools and a soldering iron, then this hack is fairly easy to do as long as you can find away to open the cover on your donor camera. Once completed, the resulting relay controller will allow any external electronic device to focus and then take a photo, essentially duplicating the operation of the two position shutter release trigger on your camera. Also, note that your camera will not be usable for regular photography after this hack as the original shutter release switch will be removed.

Figure 1 - This camera will be converted for external shutter control

The sacrificial camera shown in Figure 1 is an HP Photosmart M547 digital camera with an 8 megapixel imaging system. This camera has been around the world and dropped in an ocean, but despite some dents and scratches it still functions perfectly, so it will begin a new life as a covert spy gadget. To open one of these small digital cameras, you will need a set of tiny screwdrivers, a small knife and a whole lot of patience. Since the goal of manufacturing is to keep costs to a minimum, the cases on these cameras are often snapped together, which will require some careful prying to open them up. 

 

<< Read more about this and other DIY electronics projects >>

LED Array Illuminator - Create a high power long range night vision illuminator from a large array of infrared LEDs

A long range infrared illuminator can be made using many LEDs There are times when the small infrared LED ring built into a security camera will not cover the range or field of view you require, so you will need to find another invisible light source. Some large infrared illuminators use powerful incandescent light sources that are passed through an infrared pass filter, causing only the infrared component of the light to come through the filter. These types of infrared illuminators create intense heat due to the fact that the white light source must be fully enclosed and burn the unwanted light energy off as radiated heat. Because of this intense heat, incandescent filtered illuminators cannot be used indoors and may not be suitable for many outdoor installations. The good news is that LEDs can be used to create a very powerful infrared illumination system if you use enough of them. Ok, you need a lot of them, but these days they can be purchased for only pennies a piece if ordered in quantities of hundreds or more. The bad news is that you will need to do a lot of soldering, even on a small array of 16 by 16 LEDs, which will have more than 512 connection points. Of course, many circuit board houses offer proto service and you could have a very large LED array circuit board made for under $100 if you shop around. If you are patient and like to solder, then any size array can be made on some perforated circuit board, resulting in a very high power illumination system that will only cost you 1/10th of what a manufactured unit would cost.

Figure 1 - LEDs purchased in large quantities can often be found at bargain prices

Before you decide on making a huge array that will light up an entire city block, do a little research on bulk LED prices and power requirements because an array will become hungry on both counts. I built two version of the LED array - one using a hand wired perforated board having 13x19 LEDs and a much larger PCB version having 32x48 LEDs. So the smaller LED array has 247 LEDs and the larger array has a whopping 1526 LEDs! Make no mistake - it takes a good chunk of power to crank up 1526 LEDs to their maximum potential, and even at 10 cents per LED, that adds up to $154 just for the LEDs.

Start by calculating how much infrared radiation you will need in order to light your scene. Limitations will likely be the focal range of your camera since details are lost on most security cameras after about 50 feet. This distance is also about as far as an LED can reach, no matter how many you add to the array, so the equation then becomes how wide and how bright do you need the scene? A 20 foot by 20 foot interior room will shine like mid-day with an array of 16x16 LEDs at each corner of the room, but the massive array I built is almost too bright to be used indoors.

If your camera will stay in a fixed position, then a single array is best, but for general room illumination, it is better to divide up your LEDs into two or more arrays for even lighting. Think of a 16x16 LED array to be about the same as a typical hand held flashlight for both output power and field of view. My 32x48 array acts more like a 500 watt halogen light source when placed in a small room.

There are several varieties of infrared LEDs, ranging in size, field of view, output power, and effective light color. The most commonly used infrared LEDs output 940 nanometer infrared light which is far beyond the human visual range, and fairly detectable by any non filtered video camera. There are also infrared LEDs available for the 800 to 900 nanometer range. These are even better for use in night vision applications, but there will be slightly detectable red glow as the human eye can faintly detect this band of light.

If you have seen an outdoor night vision security camera after dark, then you are probably familiar with this dull red glow. The LEDs shown in Figure 1 are commonly available 940 nanometer types purchased in bulk from an Internet based supplier.

<< Read more about this and other DIY electronics projects >>

Laser Night Vision - DIY electronics project

Experiments using high power infrared laser diodes and modules for night vision illumination. 

     

Build a long range laser night vision illuminator

Infrared LEDs are the most widely used source of infrared radiation for night vision illuminators because they are inexpensive, easy to connect, and possess no safety hazards because they are human eye safe and do not radiate much heat. The drawback to LED based night vision illumination systems is that they are not really useable at distances of more than 100 feet no matter how many LEDs you use in the array. Filter based night vision illuminators that change visible light into infrared light are capable for much greater distances, but they suffer from huge energy losses due to massive heating of the filter material and because of this, require massive amounts of current and are only suitable for outdoor use. A laser on the other hand, is capable of extremely long distance illumination and is probably the most energy efficient source of bright light possible.

The main problem with using infrared lasers to create night vision illuminations systems is that there are safety issues that must be addressed, especially when using lasers with a rating higher than Class IIIa, or lasers that have an output power of more than 5mW (milliwatts). Class IIIb and Class IV lasers can output as much as 500 mW, and they are certainly not eye safe, especially when highly focused. A laser that outputs only 50 mW may seem like nothing, but be aware that instant eye damage could occur if you hit your retina with a focused beam. Using infrared lasers makes this situation so much more dangerous because you cannot see the beam, and your blink reflex will not help save your vision in the event of an accidental exposure to the laser beam.

Do not continue with any of these experiments unless you are well aware of the dangers involved and have proper laser safety equipment and experience in using higher powered lasers. You can still create a useable short range laser illuminator using a lower power 5mW infrared laser diode or module, so consider starting with a Class IIIa laser if you want to experiment with laser night vision illumination.

<< Read more about this and other DIY electronics projects. >>

Camcorder Night Vision DIY project

Convert any camcorder for use as a stealthy portable night vision system 

This camcorder uses a spy camera to see invisible infrared light

Camcorders a generally designed for well lit scenes, using the light to create a quality color image for recording. To ensure that the image is seen by the camera in a similar way to our eyes, only the portion of the light spectrum that is visible to our eyes is processed. Infrared light falls just below red on the light spectrum, making up the wavelengths from about 750 nanometers to about 1500 nanometers. This light cannot be seen by human eyes, but it can easily be seen by the CCD imaging system in the camera, allowing it to be used as a night vision viewer.

Unfortunately, you cannot simply add an infrared illuminator to your camcorder and use it to capture night vision video because the CCD imager contains a glass filter that blocks out most of the infrared light. The good news is that most camcorders allow a secondary video input to be recorded, and by feeding the output from a small black and white spy camera into this input, you can give your camcorder the ability to record night vision scenes that have been lit by some type of infrared illuminator.

This project uses an inexpensive camcorder and a $20 black and white spy cam along with one of the LED illuminators shown earlier to create a portable stealthy night vision camcorder.

Figure 1 - Any camcorder with an external video input will work for this project

Most video camcorders allow an external video source to be plugged in, essentially replacing the built in CCD imager with some other compatible video source. This video input will often have some custom manufactured input jack with a label of "external", "line input", or "AV input". You will need the cable that came with the camcorder in order to make this project as each manufacturer will have its own special cable for that model of camera. On the older tape based camcorders like the one shown in Figure 1, there was a 1/8 jack "standard", that used a 4 ring 1/8 inch male plug like the one shown in Figure 1, allowing any composite video source to be fed into the camera.

You will have to identify both the external video input and acquire the proper input cable in order to build this project, but if you kept all of the accessories from your camcorder, then that odd cable will probably be still sitting in the box, as it usually not used. Some manufacturers like to chisel the customer out of more money by making their own special connectors and then charging a ridiculous amount for the cable, so check your camcorder manual to make sure your camera supports video input and that you can acquire the necessary cables for a fair price.

<< Read more about this and other DIY electronics projects >>

Infrared Light Converter - DIY electronics project

Create a handheld infrared illumination system using a flashlight and common materials

This project will explore several ways to convert visible light into infrared light

Although infrared LEDs are the most common source of invisible light for a night vision device, they are certainly not the only option available, nor are they always the best. Depending on your camera type and setup, you may need a hand held source of infrared light that can be rapidly moved around the scene, or possibly an infrared light source that differs in wavelength from the standard 800 nanometer to 950 nanometer wavelength of the standard infrared LEDs.

Infrared light falls just below red on the light spectrum, making up the wavelengths from about 750 nanometers to about 1500 nanometers. This light cannot be seen by human eyes, but it can easily be seen by most video cameras, making it useful as a covert lighting method in night vision systems. Some video cameras can even see part of the ultraviolet light spectrum from 200 nanometers to 400 nanometers. That will be covered here as well.

The goal will be to pass white light through various materials that will attempt to block out all of the visible light and only pass the light that is invisible to the human eyes, yet visible to most security cameras and spy cameras.

Figure 1 - Infrared pass filters can be made from many different materials

A filter that blocks out all light except for the small portion of the spectrum that falls between 800 nanometers and 1000 nanometers is called an infrared pass filter. This effect is exactly the same effect seen by placing a colored lens over your eyes to see the world in a different color tone. If you place a green piece of translucent plastic over your eyes, the world will look green because only the light from the 490 nanometer to 560 nanometer wavelength will reach your eyes.

An infrared filter will do the exact thing, but since you cannot see infrared light, the filter material will seem completely dark to your eyes. When you place an object made of translucent infrared material in front of a video camera, it will look completely clear, as if the camera has some special ability to see through a solid object.

This infrared pass filter effect can be exploited to create a very powerful infrared illuminator by passing white light through the filter to extract and send out only the infrared light that the video camera can see. The benefit to this approach over using infrared LEDs is that a very small and powerful illuminator can be made, as well as a very large and extremely bright illuminator.

The objects shown in Figure 1 all exhibit some infrared passing abilities, which will be explored using a small black and white security camera and some white light from an incandescent flashlight bulb.

<< Read more on this and other DIY electronics projects >>

LucidScience online

Ion Ray - LucidScience forum

"I am working on making an ion ray (based on the plans at http://www.freeinfosociety.com/article.php?id=113) and had a few questions. "

Read more and join the discussion: Ion Ray

LED Array Illuminator

A long range infrared illuminator can be made using many LEDs

There are times when the small infrared LED ring built into a security camera will not cover the range or field of view you require, so you will need to find another invisible light source. Some large infrared illuminators use powerful incandescent light sources that are passed through an infrared pass filter, causing only the infrared component of the light to come through the filter. These types of infrared illuminators create intense heat due to the fact that the white light source must be fully enclosed and burn the unwanted light energy off as radiated heat. Because of this intense heat, incandescent filtered illuminators cannot be used indoors and may not be suitable for many outdoor installations.

The good news is that LEDs can be used to create a very powerful infrared illumination system if you use enough of them. Ok, you need a lot of them, but these days they can be purchased for only pennies a piece if ordered in quantities of hundreds or more. The bad news is that you will need to do a lot of soldering, even on a small array of 16 by 16 LEDs, which will have more than 512 connection points. Of course, many circuit board houses offer proto service and you could have a very large LED array circuit board made for under $100 if you shop around. If you are patient and like to solder, then any size array can be made on some perforated circuit board, resulting in a very high power illumination system that will only cost you 1/10th of what a manufactured unit would cost.

Figure 1 - LEDs purchased in large quantities can often be found at bargain prices

Before you decide on making a huge array that will light up an entire city block, do a little research on bulk LED prices and power requirements because an array will become hungry on both counts. I built two version of the LED array - one using a hand wired perforated board having 13x19 LEDs and a much larger PCB version having 32x48 LEDs. So the smaller LED array has 247 LEDs and the larger array has a whopping 1526 LEDs! Make no mistake - it takes a good chunk of power to crank up 1526 LEDs to their maximum potential, and even at 10 cents per LED, that adds up to $154 just for the LEDs.

Start by calculating how much infrared radiation you will need in order to light your scene. Limitations will likely be the focal range of your camera since details are lost on most security cameras after about 50 feet. This distance is also about as far as an LED can reach, no matter how many you add to the array, so the equation then becomes how wide and how bright do you need the scene? A 20 foot by 20 foot interior room will shine like mid-day with an array of 16x16 LEDs at each corner of the room, but the massive array I built is almost too bright to be used indoors. If your camera will stay in a fixed position, then a single array is best, but for general room illumination, it is better to divide up your LEDs into two or more arrays for even lighting. Think of a 16x16 LED array to be about the same as a typical hand held flashlight for both output power and field of view. My 32x48 array acts more like a 500 watt halogen light source when placed in a small room.

There are several varieties of infrared LEDs, ranging in size, field of view, output power, and effective light color. The most commonly used infrared LEDs output 940 nanometer infrared light which is far beyond the human visual range, and fairly detectable by any non filtered video camera. There are also infrared LEDs available for the 800 to 900 nanometer range. These are even better for use in night vision applications, but there will be slightly detectable red glow as the human eye can faintly detect this band of light. If you have seen an outdoor night vision security camera after dark, then you are probably familiar with this dull red glow. The LEDs shown in Figure 1 are commonly available 940 nanometer types purchased in bulk from an Internet based supplier.

<< Read more on this and other electronics DIY projects >>

Pulsed LED Illuminator - DIY electronics project

An infrared illuminator can be pushed to the max using pulsed current

Although there are certainly limitations to how much light (or infrared radiation) can be emitted by an LED, there are tricks that can be used to push them to their ultimate maximum limits. This project will demonstrate how a simple infrared illuminator can be "pushed" a little more in order to extend the useful range of a simple night vision system using a camcorder and a low lox monochrome camera. In order to build this project, you will need to have the datasheet handy for the LEDs you plan to use so that you can determine the amount of current the LED will withstand in pulsed mode operation.

Pulsed mode operation means that the LED will be turned on and off at a very fast rate using more current than it could withstand continuously. The purpose of doing this is to force the LED to output short bursts of much brighter light (or infrared radiation) than it normally would, and by keeping the pulse with duty cycle short, the LED will not overheat. Television remotes do this to create sharp intense bursts of modulated light to send out to the receiver, and many low voltage consumer devices do this with visible LEDs to make them appear brighter while at the same time conserving power. A pulsed visible LED may look 10 times brighter, yet consume only half the power in pulsed mode operation. Of course, there are limitations to pulsing LEDs, and you may find that using more LEDs or higher current LEDs to be more effective than using a pulse mode driver.

This project will explore the strengths and weaknesses of the pulsed mode operation of both visible LEDs and infrared LEDs, and compare both using a low lux monochrome spy camera connected to a camcorder and small infrared illuminator.

Figure 1 - This is a pulsed mode illuminator taken from an outdoor security camera

Most newer outdoor security cameras now include an infrared ring light illuminator to enhance their ability to see in the dark. Infrared light falls just below red on the light spectrum, making up the wavelengths from about 750 nanometers to about 1500 nanometers. This light cannot be seen by human eyes, but it can easily be seen by many video cameras, making it useful as a covert lighting method in night vision systems. A common example of infrared light is the medium for communication between your remote control and television set. The LED on the end of your remote sends out pulses of infrared light which is received by the infrared detector on the TV and demodulated back into data. Of course, you cannot see the pulses because they are out of our visual range, but any video camera that is not equipped with an infrared filter can see this light easily.

Figure 1 shows an infrared LED illuminator ring taken from a small outdoor security camera. There are 17 infrared LEDs arranged in a series parallel configuration around a small hole where the camera lens would be installed so that the light is spread evenly around the field of view. This is an older illuminator, and was also a pulse mode system, which is why there are semiconductors on the rear of the circuit board. An illuminator without a pulse mode driver will not have any semiconductors as it is wired directly to the DC power source, giving each LED its maximum voltage and current all of the time.

You may notice that the semiconductors on the back of the illuminator shown in Figure 1 are completely fried , which is one of the downfalls of having more circuitry - more points of failure. This circuit was either zapped by a nearby lightning surge, or simply gave it up after overheating, causing a massive failure in almost all of the transistors in the circuit. Luckily, the LEDs survived and found their way into my junk collection. I have a very extensive collection of infrared enabled security cameras, and the interesting thing is that almost all of the newer ones have better night vision capabilities and do not use pulsed mode LED drivers. Maybe the manufacturers decided that better LEDs made more sense than pushing lower quality LEDs to their ultimate maximum ratings?

 << More on this and other electronics projects, tutorials, videos and help >>

Some of my spy gadgets - LucidScience forum

"Hi, as this is my first post, I will introduce myself.
I purchased Brad's book 101 Spy Gadgets For the Evil genius two years ago, since then I have made several projects. Here are some. "

Read more and join the discussion: Some of my spy gadgets

VGA guide - LucidScience forum

"I've been looking with interest at your VGA guide, so firstly thanks for creating it :"  Read more and join the discussion:  VGA guide

Spy Camera Basics Tutorial

Micro spy cameras are inexpensive and easy to install in covert locations

At one time, a decent low light video camera was the size of pop can and cost several hundred dollars. Now, you can purchase a decent micro spy camera that will fit into a marker lid for well under a hundred dollars. Tiny security cameras also offer a huge variety of lenses to allow for practically about any angle of view and covert installation. These cameras are also very easy to connect since they have used the same basic video standard since the invention of the television.

This introduction to security cameras will give you the required basic information needed to install and power up practically any type of security camera.


I use these small video cameras for security work, machine vision experiments and robotic projects. They range in size from half an inch square to a quite large depending on the features, imaging system, and type of lens installed. For most security installations, a small board camera with a fixed medium to wide angle lens will be perfect, but there are times when you need to see a much larger area or over great distances, so these cameras have several body types that allow the use of multiple lens styles.

Extremely tiny spy cameras will not have this option, as they use a very tiny glass or plastic lens built right into the housing. There will be a bit of a trade-off between image quality and size.

 

Figure 1 - A few of the basic security cameras in my ever growing collection

For most covert work, size will be the key factor in camera selection, so you probably won't be dealing with multiple lenses or even have a choice. In Figure 1, you can see the huge difference in size between the long range motorized lens telephoto camera on the left and the tiny spy camera at the front of the photo. The tiny spy camera has a simple fixed medium angle lens and will run from a 6 volt power source for many hours. The larger camera uses a computer to control the motorized zoom lens and requires multiple power sources and electronic control systems in order to operate. 

Of course, the zoom lens can see the color of your eyes from 500 feet away, but the tiny spy cam can be hidden just about anywhere. There will always be a camera available to suit your needs as long as you have the budget to afford it. 

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Build a simple ring light infrared illuminator that will add night vision to a spy camera

Infrared LEDs are invisible to humans but visible to security cameras

Infrared light falls just below red on the light spectrum, making up the wavelengths from about 750 nanometers to about 1500 nanometers. This light cannot be seen by human eyes, but it can easily be seen by many video cameras, making it useful as a covert lighting method in night vision systems. A common example of infrared light is the medium for communication between your remote control and television set. The LED on the end of your remote sends out pulses of infrared light which is received by the infrared detector on the TV and demodulated back into data. Of course, you cannot see the pulses because they are out of our visual range, but any video camera that is not equipped with an infrared filter can see this light easily.

There are many good quality security cameras available on the market that include a low lux video camera in a weather proof housing along with an array of infrared LEDs for night vision applications. Of course, you may want to just make your own simple infrared illuminator for projects that you need to add night vision to. This can be done in a few hours with a few dollars worth of infrared LEDs. Black and white security cameras and small board cameras are particularly sensitive to infrared light. These ultra low lux cameras can usually be purchased for about $100 or less, especially from online sellers. Add 10 or more infrared LEDs, and you now have a night vision system that is better than those that were selling for thousands of dollars in the 1980s.

This project represents the most basic LED illuminator possible, and is nothing more than a series string of LEDs running from a DC power source or battery pack. You can build this infrared illuminator from a single LED and coin battery, or add as many LEDs as your power pack can handle. With 10 LEDs, you can easily light up a room for a video camera, and with 100 LEDs, you could light up your entire yard to make is seem like midday to a security camera. Our Night Vision Viewer projects also use infrared LEDs as an invisible light source.

Figure 2 - Infrared LEDs offer various lens types as well as wavelength and output power

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