"Put your finger." The you will hear the voice from the Fingerprint operator machine. I put fingerprint twice then it saved.  After that I tried to exit the main menu and try to verify the finger. And the result scan of my fingerprint is received by the machine.

From this, we can examine more detail how the system of fingerprint machines reading the data then being used as verification. The use of fingerprint in some ways, in case of the attendance machine,

Passwords verification, management access or other machine is different in such other way. Each of these techniques are even different. Here we describe several systems that we found for readings in some electronic fingerprint sensor system, both online and ‘stand alone’ sensor.

1. Optical
   Fingerprint reading techniques with optical recording system has a fingerprint patterns that use a flash (light). The fingerprint reader or a fingerprint scanner that being used is a digital camera.
   
   At the top layer is the area to put the tip of your finger or scan area. Under the scanning area, there is a flash lamp or light-emitting which functioned to illuminate the surface of the fingertips. Since fingerprints exposed to light, it produces a reflection of the fingertip which then captured by the receiver. The data is then stored in memory.
   
   Weaknesses:
   scanning results of this method depends on the quality of fingerprints. If the fingerprint quality is damaged or injured, then the quality of the readings will be not good. In other hand,  that this technique can be tricked with a fake finger.
   
   Advantages:
   This technique has the advantage; easy to do and low cost.
   
   
2. Ultrasonic
   Ultrasonic is sound or vibration with very high frequencies and cannot be heard by human ears, that is approximately above 20 kilo Hertz. Ultrasonic waves can propagate in a solid medium, liquid and gas.
   
   This technique is similar to techniques used in the medical world such as disease or an ultrasound detector. In this technique, it used very high frequency sounds to penetrate the epidermal layer of skin. High frequency sounds are made ​​by using piezoelectric transducers. The frequency reflection is received using a similar tool. Furthermore, the reflection pattern is used to compile fingerprint image.
   
   With ultrasonic readings, dirty hands is not a problem. Likewise, the surface of a dirty scanner will not impede the reading process.
   
   Weaknesses:
   Because this system has the advantage of ultrasonic technology, then it cost more expensive.
   
   Advantages:
   Ultrasonic system not only detects the surface or texture, but more detailed prints up to the epidermal skin, so the dry fingers or peeling skin is not a problem.
   
   
3. Capacitive
   A technique capacitance measurement of fingerprint image. The scan area and the skin of the fingertips is become the contact to the capacitor of this system.
   
   Because the texture of the fingerprint is ridge (mound) and there is valley, then the capacity of capacitors of each person will be different.
   
   Weaknesses:
   The Capacitance reading system requires the existence of static electricity on hand. To eliminate static electricity, the hands should be grounded
   
   Advantages:
   This system require detail so it will takes  relatively longer than other reading systems. However, Today this system was developed with the reading level of accuracy that can be arranged.
   
   
4. Thermal
   Thermal Technics is a reading system that using the temperature difference between the ridges (bumps) with the valley on the texture of a fingerprint to identify the fingerprint pattern.
   
   How that is done is by sliding the fingertips (swap) on the layer scan area. If the fingertips just putted in a short time, the temperature will be the same because of the balance.
   
   Weaknesses:
   Because the system is reading the temperature of the fingertips, it is required to the finger for having a normal condition and the time to move or rub your finger on to the data for validation
   
   Advantages:
   Today, this fingerprint reading system is  developed a lot of interest because the required scan area relatively smaller compared with other reading systems.

Here are some techniques of fingerprint sensor readings system,  following the strengths and weaknesses of our reports from various reliable sources in the field of fingerprint technology.