When developing Proximity-related Bluetooth applications, developers need to choose between different signal strength measurements. For example, should my application use RX or RSSI? To better understand this issue, let us review the basic concepts of radio frequency (RF) communication.
RX and RSSIRT communication (Real TIme CommunicaTIon, real-time communication) uses RX and RSSI (Received Signal Strength IndicaTIon) to measure the radio signal strength. Both are power level indicators received by the antenna. The difference is that the unit of measurement for RX is milliwatts (mW) or decibel milliwatts (dBm), while RSSI is the percentage of signal strength. The higher the RSSI value, the stronger the signal. Unlike RX, RSSI is a relative measurement method, mostly defined by the chip manufacturer. RSSI has no standard physical parameters. For example, Vendor A may have a RSSI maximum of 100, while Vendor B may have an RSSI interval of 0 to 127. However, on a particular chip, the mapping between its RSSI value and a particular physical RX value is known. For some platforms, the high-level API only provides RSSI data.
RSSI of different radio chips is differentYou may notice that the RSSI value may change even if the position and distance are fixed. One of the reasons may be the hardware/radio platform. For example, the chipset of an iOS device is mostly the same, the RSSI value can reflect the distance very accurately, and the same RSSI value is likely to indicate the same signal strength value on iPhone A and iPhone B. However, there are various types of Android devices, and the chipset used by the devices is also different. The absolute value of RSSI cannot accurately reflect the distance. The same RSSI value may indicate different signal strengths on different Android phones. Still, if developers can understand the trend of RSSI values, it's still very helpful for getting close to the application. Trends can also give you a lot of useful data.
How to use RSSI in close to the appAvoid using RSSI absolute values, and adopt trends. Based on fluctuations in radio signals, we can understand the relatively accurate RSSI trend. It is not difficult to understand the strength of the signal, so you can determine whether the user is close to or away from the signal source. More ideally, if we understand the specific mapping between RSSI and the location of a particular receiving device, we can make a relatively accurate judgment of the distance.
The following is an example of the relationship between RSSI and distance:
The nature of RF communication determines that RX and RSSI are largely affected by various environmental factors. When using the RSSI value, environmental factors can also cause values ​​drift within a certain range. To combat these effects, developers can design a sampling algorithm to obtain the majority (the most frequently occurring value) of the RSSI sample set for a specific time period. In this way, the data can more accurately reflect the actual signal strength and filter out the noise.
in conclusionWhen approaching applications choose to use RSSI, developers need to consider different definitions of different chip vendors. The absolute RSSI values ​​of different radio chips may be different, but we can still get a lot of information from the RSSI trend of the same chip. To avoid environmental interference, developers can define their own sampling algorithms to remove noise.
Antenk battery holders are manufactured from UL rated 94V-O materials. Contacts made of high quality spring steel to assure reliable connections and allow contact resistance. Each contact is clearly marked with its polarity to assure proper battery insertion.
Lightweight and rugged, these PCB coin cell holders offer uniquely designed notched battery slot that assures quick and easy insertion and replacement of all major battery manufacturers' lithium coin cells.
Coin Cell Battery Holders
We have created a wide variety of coin cell battery holders for use in all types of devices, and from handheld medical devices to server motherboards we have solutions for any application. The ever increasing types, sizes, and sheer number of devices which use coin cell battery holders have been keeping us busy, and we have a similarly increasing selection of coin cell battery holder designs. After all, the perfect coin cell battery holder for a handheld medical device is going to be vastly different from the one for a server motherboard.
Lithium Coin/button Cell-Holders Battery Holders
Compact and vertical holders allow battery insertion and replacement from the top, making them ideal for high-density packaging
compact and vertical holders allow battery insertion and replacement from the top, making them ideal for high-density packaging, which maximizes board placement choices. The through-hole mount (THM) versions feature an "air-flow" support-leg design that facilitates soldering and quick battery insertion. The surface-mount (SMT) versions feature a "flow-hole" solder tail design for increased solder joint strength and are available on tape-and-reel.
These holders are manufactured from UL rated 94 V-0 materials. Contacts are made of high-quality spring steel to assure reliable connections and allow contact resistance. Each contact is clearly marked with its polarity to assure proper battery insertion.
Lightweight and rugged, these PCB coin cell holders offer a uniquely designed notched battery slot that assures quick and easy insertion and replacement of all major battery manufacturers' lithium coin cells.
Features and Benefits of Coin/button Cell-Holders Battery Holders
Low profile for high-density packaging
Reliable spring-tension contacts assure low-contact resistance
Retains battery securely to withstand shock and vibration
Rugged construction, light weight
Unique notched battery slot assures quick and easy battery insertion and replacement
Compatible with vacuum and mechanical pick and place systems
Base material UL rated 94 V-0. Impervious to most industrial solvents
THM "air-flow" design pattern enhances air circulation around battery
SMT "flow-hole" solder tail design for increased solder joint strength
Clearly marked polarities to help guard against improper insertion
Unique Coin Cell Battery Holders
Antenk has pioneered a large number of new styles of coin cell battery holders to suit the various needs of the electronics industry. Our Verticals are an excellent way to save space on a crowded board, while our Minis can save almost 3 mm in height above the PCB over traditional coin cell battery holders. Gliders are an excellent upgrade over coin cell retainers, offering more reliable connections while also having simple, tool-less battery replacements. Our newest technology is Snap Dragon, which adds a snapping cover to the traditional style of coin cell battery holders for increased reliability.
Coin Cell Battery Holders by Size of Cell
191 | 335 | A76 | CR1025 | CR1216 | CR1220 | CR1225 | CR1620 | CR1632 | CR2016 | CR2025 | CR2032 | CR2320 | CR2325 | CR2330 | CR2335 | CR2354 | CR2420 | CR2430 | CR2450 | CR2477 | CR3032 | Coin Cell | F3 iButton | F5 iButton | LR1120 | LR44 | ML414 | SR512SW | SR60 | V80H or CP1654 | iButton | BR1025 | BR1216 | BR1220 | BR1225 | BR1620 | BR1632 | BR2016 | BR2025 | BR2032 | BR2320 | BR2325 | BR2330 | BR2335 | BR2420 | BR2430 | BR2450 | BR2477 | BR3032 | Other Sizes
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