A spy pen camera is an example of electronic miniaturization because it contains tiny versions of larger equipment, such as a still photo camera or an audio/video recording system. All of its inner components are connected by very narrow wires; a pinhole camera system is used with a small viewing lens near the top of the pen case. Besides a choice of video or still image capabilities in black and white or color, spy pen cameras are available with various memory capacities. The amount of memory corresponds with the number of stored photos or length of video footage a particular spy pen camera can hold. All of the working mechanisms of this spy device are hidden inside a case that not only looks identical to a ball point pen, but writes like one as well.
Some pen cases are slimmer than others, but virtually all of these types of spy cameras look realistic. They are usually designed like the classy style of business pen and may be in any color, but are often in rich jewel shades such as deep red or dark green. Although all spy pen cameras can be used as a regular writing instrument, some types have limited ink supplies because the cartridge is small. Other hidden camera pens take standard ink refill cartridges. The clip on section of a spy pen camera, as well as the clicking mechanism on its top, can usually be moved to turn the different features on and off.
People use spy pen cameras for many different purposes; for example a parent may use one to be sure the nanny she hired to watch her child is not being abusive. Many people want to get video or photos, plus voice recordings, to help prove their case in court against a person who is they believe is lying. Evidence recorded using a spy pen camera is often admissible in court, but this will depend on the country. In jurisdictions, or governing areas, where that type of evidence is permitted, spy pen cameras with an audio video interleave (AVI) recording format may be required. AVI basically means that both audio and video can be played at once; having the date and time details on the screen is also a spy camera feature favored by many courts.
Some camera spy pens are made for mobile use, while others work better when left in one place to record sounds and sights. If left to run constantly at one time, spy pen cameras vary in how long their battery will last before recharging is necessary. It may be anywhere from 1.5 to 5 hours, depending on the machine's quality and features. The battery is usually located in the upper part of a spy pen camera. Some battery cases may be difficult to access due to the small size of spy camera pens, but most are designed to charge in a car or on a travel-type of charger.