Some time ago we presented a technical article introducing the borescope. Extremely useful measurement and diagnostic tool when evaluating dark and / or hard-to-reach areas across a wide variety of applications, the borescope It is frequently used in automotive and aircraft mechanics workshops, as well as in inspection operations that include, among others, the construction industry, welding workshops, sewage systems and the manufacture of auto parts and firearms.
As we detailed in the aforementioned article, there are different kinds of borescopes, each designed for every need. However, the borescopes provided with camera (or videoboroscopes) or, as they are generally known in the trade, digital inspection cameras, capable not only of taking images and / or videos to later play them on larger screens, but also of moving and removing small objects such as bolts or nuts, they are enjoying increasing popularity among mechanics, plumbers, electricians, and plumbing installers. ventilation and many others.
Today we have digital inspection cameras with small screens, extra large screens, color, black and white, small and large camera heads, wireless functionality, built-in and removable memory, PC and TV connectivity, built-in battery and much more. When we look at all these details, choosing a suitable camera can seem extremely complicated, but, as always, if we follow a series of criteria we will see that our decision will be much easier.
In this installment we are going to deal particularly with the digital inspection cameras medium price, like the one we see in the following video, offering a series of suggestions to take into account when we must acquire one of these instruments.
So that you can guarantee us a good view of areas that the human eye cannot access, a digital inspection camera it must offer us, at a minimum, the means that will enable us to comfortably achieve that goal. To this end, the most important specifications of a digital inspection camera that we must consider when we want to choose one in particular, are the following:
Camera head diameter
This parameter is related to the use that we will give to the camera. If we are auto mechanics or work with very confined elements, we should look for small diameters: 8 mm is the standard for most applications in gasoline engines, while 5.5 mm or less is the standard for diesel engines. If we are plumbers or carry out frequent inspections of pipes or drains, larger diameters are convenient for us. There are generally two standards for these cases: a diameter of 9.5 mm and another of 17 mm.
Borescope Flexible Cable Length
This cable is the one that carries the camera lens at its end and is the “arm” of the instrument that allows us to “enter” into cavities that are difficult to access. Obviously, a cable that is too short may not be sufficient for certain areas we wish to inspect, for example a motor or pipe. Flexible cable lengths are usually related to the diameter of the camera head and most of the digital inspection cameras They offer flexible cable lengths of 0.90 m (for a head diameter of 9.5 mm) and 1.20 meters (for a head diameter of 17 mm).
Lighting device / s
For access to dark and confined places, lighting is essential, so we must make sure that the camera we choose has one or more powerful LED lights, mounted on the camera head, as we see in the figure below. This guarantees us excellent lighting clarity.
Borescope Illumination Levels
If in addition to having powerful LED lights, we must adjust the lighting intensity according to our needs, it will be convenient to look for a digital inspection camera that has buttons for more intense lighting and less intense lighting. In the trade we can find cameras that incorporate up to nine levels of illumination, which allows us to achieve the appropriate light intensity for each situation.
Resistance to water and dust
If we are plumbers, on more than one occasion we will have to inspect with our boroscoio very humid places or, even, under water, such as pipes, drains or toilets, for example. If we frequently inspect cavities in the walls or ventilation pipes, for example, the soot and dust inside can also be a challenge to achieve a good vision. Given these requirements, it is essential that both the flexible cable and the camera head are totally waterproof, and that the head has a smooth surface, which will ensure perfect vision in environments that contain solid particles in suspension.
Depth of field of the lens of a borescope
In reference to a borescope, videoscope or Inspection Camera, the depth of field or focal distance is the distance, measured from the instrument lens, at which an image can be clearly distinguished. Typically, it is expressed as a minimum and a maximum distance, for example 30mm to infinity. This means that if the instrument lens were to get closer than 30mm the image would be blurry and if it went beyond infinity the image would be too “grainy” to be of use. However, it should be noted that manufacturers do not determine the depth of field in real conditions. Light can be a limiting factor, preventing an image from being sharp within the indicated depth of field. For example, even though the factory specs say the maximum distance is infinity, let’s not expect our camera to get sharp images in a dark, oversized tank or enclosure. It is important, however, that the device can offer us a clear image of an object at a relatively large minimum distance, that is, between a camera with a depth of field of 20 mm and another of 30 mm, it is advisable to choose the latter, as the lens does not need to get so close to the subject for it to appear sharp.
Screen size and resolution on the borescope
The quality of the images captured by the camera and the way they are displayed is a factor of great importance. Many digital inspection cameras They offer a screen size of 2.4 inches with a resolution of 320 × 240 pixels. Others less common have a 3.5-inch screen and others allow a resolution of 320 × 480 pixels. As with computers or cell phones, a larger screen will provide more viewing comfort; however, in many cases, resolution is paramount. The important thing is to achieve a balance according to our needs.
Our digital inspection camera it needs power to power the camera itself, the screen, and the LEDs. That energy can be provided by common AA type batteries or by a rechargeable battery pack, generally, of lithium ion. The decision for one type or another will also be conditioned by use. AA batteries free us from dependence on an outlet to recharge the pack and can be the ideal option if we are only occasional users of the device. On the other hand, if the use is frequent and intensive, we must decide on a digital inspection camera that includes a lithium ion battery pack (commonly 10-12 V) that, depending on the intensity of the light used in the camera, offers a range of 7 to 15 hours. Some manufacturers supply their batteries with a electrical protection system against overcharging, overheating and deep discharge to ensure maximum performance, and they even incorporate a charge level indicator, which shows the remaining battery life.
Suppose our borescope shows us a problem in the material it is inspecting; Ideally, we should be able to solve that problem on the spot. For example, if we drop a nut inside a motor and the camera identifies exactly where it is, then it would be very practical to be able to remove it easily. For this, the digital inspection cameras They usually come in a kit that includes a number of very useful accessories. The main accessories that we must procure are:
a) Hook, magnet and mirror: They can be attached to the camera head as shown in the figure above. The magnet and hook are suitable for moving and removing small and light objects that do not require great force; otherwise the camera or accessory may be damaged. The mirror makes it possible to further improve the range of vision.
b) Connection cable to external monitor: allows you to view the image of the digital inspection camera on an external monitor or even a television capable of receiving NTSC or PAL video signals (depending on the manufacturer). To do this and as can be seen in the following figure, simply connect one end of the cable to the video output of the digital inspection camera and the other end is connected to an appropriate monitor, the appropriate place for this connection may vary according to the model, it will be the user manual that can help us in each case.