DIPOL Weekly Review – TV and SAT TV, CCTV, WLAN

How to sense touch in virtual reality?

A Dutch-French group of scientists has published in the Journal of The Royal Society Interface the idea and research of a new haptic screen. The device uses ultrasounds to mimic the sensation of touch. Made of glass, the flat screen can mimic an interface built with mechanical buttons. By holding your finger on it, you can feel the sensation of touching and pressing a "physical" key.

When our fingers physically interact with objects, tools or materials, the skin is deformed. This deformation stimulates mechanoreceptors located in the tissues, which signal to the brain the properties of the material, such as its flexibility or roughness. Tactile sensations are essential for the proper fine-tuning of our motor commands. A mental map is created in the brain that reflects the physical interaction between the skin and the environment.

Normally, when a finger presses a button, the surface of the skin stretches due to friction, but when the finger releases the button, the friction decreases and the skin immediately relaxes. Specific, non-standard skin stimulation can trick the brain into perceiving objects. In the case described here, the frictional force is generated by inaudible ultrasonic waves. The sensation of touching a button can be induced not by physically moving the button, but by dynamically changing the static friction of the skin with the surface. Surprisingly, this behavior occurs even in the absence of sliding or lateral forces and on a stationary finger. Moreover, on a two-dimensional surface, it is possible to create a sensation of shape and texture.

This effect was tested on a group of 12 subjects, and the results show that in 75% of cases, a perceptible sensation of touch occurred when using an ultrasonic wave of more than 2 micrometers. However, this effect is closely related to the characteristics of the skin, such as its hardness.

In the long run, the use of ultrasound-modulated friction could have a significant impact on the development of haptic displays, enabling the creation of more realistic and authentic tactile sensations. As a result, this will have a significant impact on the development of technology and change the way people use electronic devices.

TERRA's innovative fiber optic system for RF/SAT systems – part 2.

In the previous issue of the Review we mentioned TERRA-branded new fiber optic system for RF/SAT systems enabling the distribution of signals: DVB-T/T2 and SAT from two positions, through 1 optical fiber, thanks to the use of WDM couplers and optical transmitters with different wavelengths: 1310 nm and 1550 nm.

If two optical fibers can be used in the system, the installation is greatly simplified. It is possible to use 2 optical transmitters operating at the same wavelength from which the signal is transmitted over two separate fibers. The diagram below shows an example of transmission of RF/SAT signals from two satellite positions in a dual-fiber optic cable.

Update of expansion modules connected to Hikvision IP/2-Wire video door station.

Expansion modules connected to DS-KD8003-IME1 G73652 or DS-KD8003-IME2 G73644 modular door stations can be upgraded from the main door station using the iVMS-4200 application. After adding the main door station with properly connected modules to the iVMS-4200 client application, go to the main door station settings and then: System -> Maintenance-> Upgrade. Select the Display module tab or Sub modules and provide the link to the previously downloaded firmware and confirming with Upgrade. The upgrade process begins.

Remote power supply of the PoE switch.

The ULTIPOWER 352SFP N299707 PoE switch has the Powered Device function that allows it to be powered by connecting to another PoE switch. This function is particularly handy when only one twisted-pair cable is connected to the switch installation site (and the cameras, if installed in the same place, e.g. on a pole).

Moreover, the switch has the following functions:

• Extend function that enables powering devices connected with twisted pair with a length of up to 250 m,
• PoE Auto Check automatically performs current restart of the connected device in the event of hanging. (NOTE! Turn this function off when updating the software of the connected devices.)

Fiber optic installation for cameras installed on poles.

Feeding a separate cable to each pole (mast, lantern), on which the cameras are to be installed, is the most universal and the least labor-consuming solution when it comes to attention welding and protection of optical fibers. However, this involves a greater amount of work when laying cables and the need to provide more space on the cable route.

In this topology, the design of the cable itself, i.e. the method of securing the fibers in it, is of no great importance. It is, of course, to have all the parameters necessary for proper operation in the given environmental conditions and be adequately resistant to tearing when the cable is pulled into the ducting.

The choice of the star topology also allows you to save space on the pole itself – the fiber optic cable can be inserted directly into the box, in which devices including media converter, PoE switch, video converter, power supply etc., are installed. The fiber optic, of course has to be secured with a pigtail, and the connection (splice) itself should be secured on the splices box or a dedicated optical fiber box. Then the pigtail should be plugged into the fiber optic adapter, and the connection with the device responsible for signal conversion should be made using a patch cord. Do not plug the cable directly into the device! In the future, when performing any service or maintenance work, the installer will only risk damaging the patch cord, and not the cable, which would entail the need to splice the fiber again.

SIGNAL CCTV 210/230/145 mm sealed box is R90601 designed for mounting on a pole, mast or wall. Inside, there is a mounting plate which can be easily removed, and two DIN rails for easy installation of components such as switches, power supplies, media converters or mini fiber optic distribution frames. Additionally, the box has protective wires which can be connected to active devices.

The box can easily accommodate, among others, an industrial switch, power supply, main switch and mini distribution frame in the case of systems based on fiber optic cabling (if this is the case, we recommend the use of ODF-DIN L5312 mini distribution frame). All these elements can be mounted on DIN rails or aluminum mounting plate. Thanks to adequate number and size of cable gland holes, it is possible to lead in and out the cabling for: power supply, fiber optic cable, twisted pair, for connecting up to 4 surveillance cameras.

Which optical power meter to choose? Dipol offers 3 models of optical power meters designed to perform transmission measurements and verify the absolute power available at the outputs of active devices.
Which one should the installer choose?...>>>more