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

Printed biomedical sensors.

An international team of scientists from the US and China have developed a new simple way to place electronic circuits directly on the skin and use them to build precision sensors for medical applications. The electronics are applied (scientists say “printed”) in a completely safe manner on the skin to monitor health indicators such as body temperature, blood oxygen levels, heart rate and blood pressure. Moreover, the researchers have demonstrated that the biosensors can be wirelessly connected to monitoring equipment (be it a smartphone with proper software, or even a direct Internet link) to check the results continuously.

Electronic circuits printed on the skin enable safe connection of biosensors.

So far, no good method has existed for application of electronic layers to the skin. The main issues included low strength, rigidity or high application temperatures. The scientists have succeeded in making a special coating that, on the one hand, adheres properly to the skin and, on the other hand, allows electronic circuits to be connected (“sintered”) at a room temperature. Surprisingly, the coating is made of materials that are easily accessible and often used in everyday life. It consists of polyvinyl alcohol paste, the main ingredient of facial peeling masks, and calcium carbonate, which is the main material of egg shells. The sensors stay well on the skin for several days and are easily removed by heating the circuits, e.g. with a hair dryer or in a hot bath to peel off.

The biomedical sensors have vast potential for the future of diagnostics. Biological phenomena occurring naturally in the body or symptoms of diseases can be interpreted as physical or chemical effects which can be parameterized. The body generates numerous signals, such as electrical impulses, changes in the shape or color, which can be detected by the sensors. The examination is non-invasive, and most often involves continuous measurement at the patient's home. Works are currently underway on a set of sensors which can monitor symptoms related to Covid-19 infection.

DVB-S/S2 satellite signal in a hotel system.

Headends distributing satellite programs converted to digital DVB-T COFDM format are still the most popular solution used in many hotels. Satellite channels can be an addition to the terrestrial television programs or be the only part of the package offered. TDX-480 R81621 is one of the most valued TERRA transmodulators. It makes it possible to distribute and manage SAT TV programs in a private TV system. The TDX-480 R81621 module converts the DVB-S/S2 (8PSK/QPSK) signal to DVB-T (COFDM). The device supports the reception of free-to-air channels. One TDX-480 panel receives the entire signal packet from eight satellite transponders and creates two independent groups of four adjacent DVB-T multiplexes with a maximum bandwidth of 31.66 Mbps. For scrambled channels, the TDX-420C R81619 model can be used. The devices support the SCR/Unicable system, compliant with EN50494 and/or EN50607. This means that the satellite signal can be supplied directly from the SRM-521 R80521 multiswitch in order to receive satellite programs from the entire Ku-band (frequency range from 11.70 to 12.75 GHz).

Basics of IP addressing – part 7: DynDNS service.

The previous issue discussed the details of the DNS server. This section introduces the use of the DynDNS service. To run a server, e.g. with a website or for viewing CCTV cameras, to be available from anywhere on the Internet, and if you do not have a fixed IP address, but you only receive it (public address) dynamically from a DHCP server, you have to use the DDNS (Dynamic Domain Name System), i.e. the dynamic name server service.

Subscribers connected to the Internet often do not have a fixed public IP, but it changes from time to time. In this case, the user unable to directly connect remotely to such a location. Here, the DDNS service comes to the rescue, which, like the DNS, has a database of entries of the domain and numeric address relationships, but it can be updated at any time by the domain owner (a dedicated service/application installed on user hardware notifies the DDNS server of the address change). Thanks to that, the server can be reached under one fixed name, regardless of what IP address it currently has. For that reason, you can communicate with the server only using the domain address translated by the DDNS server (unless the current numeric server address is known, but you never know how long it will be valid).

Here is a diagram of a one-cycle communication between the client and server without a fixed IP
address via DDNS. It will be repeated the next time the address is changed.

Note that it may take a short while, after the DHCP server changes the IP address, before the program or router detects that, and then it may take about a minute for the update information to be sent to the DDNS server, before the server writes the data to the DNS server. You have to bear in mind that the server may be unavailable for several minutes when the IP address changes.

What is the difference between the AGM and gel batteries?

Maintenance-free batteries are recommended for low-voltage systems. They are built to be completely leak-tight and do pose no risk of leakage of hazardous substances, so they can be used in any position. The batteries available are the AGM (Absorbed Glass Mat) or gel type.

Emu battery based on the AGM technology.
The dark elements are lead plates, while the light ones are glass fiber layers soaked in electrolyte.

In the AGM (Absorbed Glass Mat) batteries, the entire electrolyte is trapped (absorbed) in high porosity glass fiber separators between the lead plates. They have low internal resistance which means a higher voltage at the terminals and longer working time, particularly while being discharged with a high current drawn. This makes them best suited for buffer operation, i.e. they are used in UPS equipment.
The gel batteries in turn, have the electrolyte in a form of gel. They are resistant to deep discharge and are used as a power source for mobile devices such as forklifts or wheelchairs and with photovoltaic systems.

Activating the second relay of the 2nd gen. Hikvision IP video intercom main module.

The DS-KD8003-IME1/EU G73652 door/gate station main module has two relays, one of which can be used to control the electric strike of the wicket, and the other one to control the entrance gate or barrier at a housing estate. By default, the second relay is de-energized and not visible in indoor monitors or Hik-Connect and iVMS-4200 client applications. To activate it, in the iVMS-4200 (v.3) enter the Remote settings -> Intercom -> Module I/O and select the “Electric strike” option for the "DOOR2" output. After that, the second output will be activated and will be visible in the live view window of the connected monitors and client applications.

An example of a wicket and entry gate control using
the 2nd generation Hikvision IP video intercom system

In the image above, the monitor (DS-KH6320-WTE1/EU (G74001)) and the main door station module (DS-KD8003-IME1/EU (G73652)) are connected to an ULTIPOWER PoE switch (N299781), which guarantees power supply and communication between the two devices. Using a router (N3255) allows access from external networks, as well as a wireless connection in the local network. The electric door strike (G74210) is released by the 12 VDC power supply unit (M1825) via one built-in relay in the door station module. The other relay controls the entrance gate.

Tools not always necessary.

A company has erected a new building. Some of the staff was to be moved there but, sadly, no optical fiber was routed at the stage of making the conduits for wiring systems. Only cooper wiring had been designed. Due to the epidemic risk, the use of an external contractor was to be avoided. All that was needed was an appropriate optical fiber terminated with connectors dedicated to the existing equipment.

Patch cord made to order - L7370.
Optional protection of connectors for transportation and installation.

Ordering a fiber optic patch cable from DIPOL was the solution. The owner’s technical team, familiar with the facility and wiring routes, measured the required length of the cable, opened the entrances to the buildings and to the conduits. A single-mode universal cable terminated with two LC connectors on both sides was selected after assessing the needs of the facility. Moreover, the cable was placed in corrugated conduit at the factory. The connectors were protected against dirt with special covers.

The connectors of the patch cords made to order are professionally installed in the manufacturing plant with the use of the latest precision machines. The ready-to-use patch cords/cables are supplied with certificates containing insertion loss measurements. The patch cords minimize the cost and time of installation.

Heat maps in stores. Heat map is a visualization of camera image analysis showing the movement of customers. They show the key parameters for the seller, i.e. where the customers move and how much time they spend at specific shelves. This information can be used to better organize the store space and arrange products on shelves...>>>more

An in-store heat map

TRISET cables – tailored to requirements