The vibrometer can also be called Laser Doppler. It is an instrument used to measure the mechanical oscillations and counts one, two, three dimensions. The operation is as follows: 1. The laser focused on the surface to be measured. 2- The laser light varies if the focused surface moves. 3- The vibrómete check with the changes and quantifies the object being measured.

Nowadays we all have in mind the importance of controlling and verifying the bills we receive in the stores. Thanks to the different security systems implemented and the renewal of protection systems in the new current tickets, it becomes increasingly difficult to falsify, but still an extra control is highly recommended.
Counting systems or banknote detectors use the combination of vArias detection technologies to check if the ticket is false or the ticket is true.
Among the detection systems we find from the simplest (pen) to machines that verify different characteristics of the ticket to verify their authenticity.
The most common detection systems are:

1. LABEL: Simply mark the ticket to check. If the mark is displayed in black, the billetAnd is false.

Detecting machines: The most reliable, as they can combine different detection technologies such as:

1. UV: Ultraviolet detection. It allows in a visual way to verify the markings integrated in the ticket with fluorescent phosphors that can not be seen in daylight and are only visible with an ultraviolet light at a certain frequency.
2. IR: Infrared light detection: Other systemOf safety implemented in the tickets is their ink, since under a type of infrared light they exhibit a special behavior. There are two types of ink, the ink that shines when exposed to an IR light and the ink that does the opposite and absorbs the light giving a black tone.
3. MG1 and MG2: This is the magnetic detection. The tickets incorporate a magnetic security system, which is based on a band usually on the sideOf the note, of a ferromagnetic material. This security system is not visible without the proper detector. Another safety system based on magnetic detection is to print the bill with areas of magnetic ink.
4. SIZE: It is based on the detection of the ticket checking its size in length and width. Each ticket has some special characteristics and very specific in terms of measurement, each one of them is fabriTo the millimeter.
5. DD: Thickness detection. Just as each ticket has an exact size, they also have a specific thickness.

Within the detection systems we can find different types according to their operation, among them the most common:

1. Infrared sensors
2. Vibration sensors.
3. Photoelectric sensors.
4. Ultrasound sensors.
5. Acoustic sensors

Each type of sensor uses different detection methods and each one is recommended according to the situation.

1. Sensors by infraRrojos, are one of the most used types, thanks to its reliable operation and installation, since we can find this type of wired and wireless sensors.
   The infrared sensor has a phototransistor capable of detecting the infrared electromagnetic radiation emitted by a body, this type of radiation is not visible by the human eye. A change of radiation in its perimeter will activate the relay and proceed to send ato alarm signal.
   Within these, there are two models, passive infrared sensor, which only has a phototransistor and assets, which have an emitter and a receiver.
2. Vibration sensors are used mostly in security systems, such as window sensors. car alarms etc.
   Its operation is based on an accelerometer, through a piezoelectric sensor. This type of sensorDue to its construction material it allows to detect changes and pressure when emitting an electric charge.
3. Photoelectric sensors, these are the sensors that use photoelectric rays, normally a transmitter and a receiver are used, they are commonly used in automatic door systems, elevator doors, production chains, etc.
4. The ultrasonic sensors are those that emit an acoustic signalabout 30 kHz, a signal that is not appreciated by humans. This signal or wave propagates through space, walls, objects, doors, etc. once the signal has spread the sensor is activated and any change will trigger the sensor.
   These types of sensors are also used in devices that require measuring distances and detecting objects.
5. Acoustic sensors, are those that can detect the signal emitted by anyobject and are able to detect the pressures that the acoustic waves emit, such as the noise of the crystals when breaking a window.