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41

2.4 GHz is one of the industrial, scientific and medical (ISM) radio bands. ISM bands are unlicensed, which makes it easier to certify the equipment with FCC (or its counterparts in other countries). However, what special about 2.4 GHz? There is about a dozen ISM bands. Some at higher frequency, others have lower frequency. Not all ISM bands are ...


26

The "special" thing about 2.4GHz is that when spectrum was allocated for various needs in the 60's and 70's, no one wanted it, because it was thought that atmospheric water absorption made it useless.


14

It is 'special' since it does not go very far. Strangely, this turns out to be an important advantage as many devices and people can use the same band in near by area without interference. Tele density is the term used in phone industry as how many cordless phone per square mile. Early generations (25 years ago) coreless phone use few MHz and tens of MHz ...


9

The rule of thumb a lot of people use is that lower frequencies will have better "penetration" than higher frequencies. That's true in some cases, but not all. This is probably derived from calculating skin depth of materials. The skin depth is just how deeply into a material an electromagnetic wave of a particular frequency can penetrate. The equation used ...


8

Because the light link specifications haven been released yet, except for members of ZigBee alliance I don't think you will be able to at this moment. Unless you want to become a member of the Zigbee alliance. I have had contact with one of their developers who said that modules that where able to use previous specifications should also be able to use the ...


7

In Europe, you would have to comply with EN300220 which is an ETSI standard. If you use a library for the MAC layer of Zigbee, this will have been done for you, but if you write your own MAC layer, you have to take care of all the restrictions in this document yourself, and then get a test house to validate your product according to the telecomms regulations....


6

I don't think you really understand what you are talking about here. "Zigbee", or IEEE 802.15.4, is a protocol. As such, it has no "programming language". Theoretically, it's completely possible to implement a system which can handle the zigbee protocol in any programming language, assuming that whatever language you're using has adequate hardware support ...


6

I am sorry to be the bearer of bad news! There are a few things that stand out. In addition, even after these problems are corrected, there's still going to be a lot of learning and analysis to do. Please don't take my suggestions as criticism; RF is tricky :) Also, there have been hundreds of books written on RF. I can tell you some things to look for, but ...


5

The board is laid out with footprints for the components indicated, but they are not populated by default. Sometimes the acronym DNP (Do Not Populate) is used. Some variant of the board can be made with some or all of the indicated parts populated and possibly some other parts not populated. It allows various options of a board to be made with a single PCB ...


5

Music is a special case for audio latency. For speaking, or voice conversations you can have up to 100mS latency before it impedes the conversation - though it can be noticeable at that latency. Music, however, has a beat and 100mS is unacceptable. When musicians play together acoustically sound travels about 3mS/meter. On a typical stage setup band ...


5

Some of the reason is cost (both financial and power budget with distance), some is because what frequencies are reserved for other types of devices/communications and the interference caused by such deviations from those frequencies. When a frequency is chosen for widespread use, it is cheaper to use off-the-shelf parts in your design rather than having to ...


5

ZigBee (and more generally 802.15.4) targets different uses compared to WiFi (control vs data streaming), thus has lower data rate (250 kbps max) but also much lower power consumption (few tens of mW transmitting and receiving). For sure you can make star networks, but also more complex tree and mesh networks. In fact, meshing is one of the main selling ...


5

There is FW available for free. You should download TI's zstack-home from here: http://www.ti.com/tool/z-stack you the have a few options: Use IAR (this will meaning buying a license) to write a ZigBee application on the CC2530. Example Applications for the following are supplied in zstack-home SDK: Light: A light that can be turned on/off locally or ...


4

All the clues are in the answer linked to in your question. Here's a recap: - Using minimum data rate (20kbps) you need a theoretical power at the receiver of -111dBm Free space link loss at 10km is 120dB (use the formula - I've used 10km and 2.45GHz) If output power from transmitter is +10 dBm, receiver power is -110dBm That's almost a perfect match and ...


4

Minimum data rate for Zigbee is 20k bits per second and this dictates the bandwidth of the receiver. The wider the bandwidth of the receiver, the more noise the receiver picks up so running at a smaller bandwidth means that for a given transmit power, the operating distance to the receiver can be bigger. Received power needed for a given data rate is: - ...


4

I know this is an old post, but since I stumbled on to it looking for a profile I had not seen before I figure this answer may help someone else. I've been working on this for a while - I don't consider my code "publishable" yet - I'm still using it in hack-and-sniff mode to find the clusters in question, but I can say the Light Link Application Profile is ...


4

This band is reserved for Short Range Devices by ETSI. There is a sub-allocation for streaming audio with 100% duty cycle and 10 mW ERP limit, and a few allocations for digital transmissions with 0.1% duty cycle and 25 mW ERP limit. If you buy off-the-shelf components designed for this band, you should be safe. Of course this will cause interference with ...


4

The CC2650ST supports ZigBee, BLE or 6LowPan. It comes programmed with BLE by default, you need to download the BLE sensor tag app from app store and update the FW to the ZigBee image. This will update to a ZigBee image using BLE. The App has the CC2650 ZigBee image included in it, so you just need the latest app. The ZigBee FW image makes the sensorTag into ...


4

No you can not. The Hue network is a ZigBee Light Link network, and a ZigBee Light Link Network uses "secret" ZLL security keys. Home Automation networks use public security keys, and hence if this was a Home Automation (HA) profile network then you could do this. The Hue Lights will join a HA network, so if you can create a HA coordinator and reset the Hue ...


4

tl; dr: ZigBee isn’t a subset of WiFi (802.11). It is a different protocol family, just as Bluetooth is another different protocol family. ZigBee, BT and WiFi are not directly compatible with each other, but will co-exist in the same band. What Is ZigBee, And How Is It Different From 802.11, Really? ZigBee (802.15.4) is a family of protocols used for low- ...


3

The XBee devices do have built-in microcontrollers. However, Digi does not make a SDK, or the resources required to compile your own firmware image available for the Series-2 XBees. You could probably theoretically reverse-engineer the modules, and write your own firmware for them. However, judging from the fact that you're asking this question, I think ...


3

There is at least one module announced, which combines Bluetooth, ZigBee and WiFi protocols: The RedPine M2MCombo RS9113 module combines dual-band 802.11n + BT4.0 + ZigBee into an SoC. The module was announced in early April 2013, and is available for sampling to qualified companies.


3

Actually the answer from hanu is not correct. The XBee series 2 modules are ZigBee compliant (ZigBee Certification). What you called the "Digi stack" is only the application profile they use. ZigBee compliant means they use the official ZigBee stack but operate on a private application profile. If you configure your XBee Series 2 in API mode you can talk to ...


3

It depends which layer is encrypted. If the MAC layer (addresses, packet descriptors etc) is encrypted, a router would be useless. If only the packet payload is encrypted, then a router can fulfill its function.


3

The Living Colors series has two versions (AFAIK). Generation 1, which the remotes used a MSP430 microcontroller connected to a CC2500 RF Transceiver which pairs with another CC2500 in the lamp itself. Because there is an open bus between the two, someone (Sprite_TM a very awesome hacker) reverse engineered the protocol between the CC2500 and the MSP430 (PDF)...


3

Pre-certification may apply to the module you are using, but you are still required for CE marking of the device. Part of the process for CE marking requires you to show evidence that your DEVICE conforms to the relevant harmonized requirements that covers emission and susceptibility. So you are still required to obtain CE marking to sell your product on ...


3

As others have said, it's an ISM band, and all of the other listed reasons are totally valid, but I think another part of of the reason it's more popular than other ISM bands is that it is available in almost all countries whereas some ISM bands are only ISM in certain regions, and it is also fairly wide compared to other ISM bands. As you go up in ...


3

1- Depend on the manufacturer of your ZigBee maybe it provides a setting/configuration to increase the range. You should provide information about manufacturer and model. 2- Technically it is possible to increase the range of your signal improving the: Antenna (gain, sensitivity to body effects etc.)- Choose an external antenna with a good gain and ...


3

One of the disadvantage associated with zigbee modules for communication is the high cost. Moreover Zigbee is intended for short range. Radio links are the cheapest and long range solutions. NRF24L01 is one such radio link solution. NRF24L01 comprises 2Mbps RF transceiver IC for the 2.4GHz ISM (Industrial, Scientific and Medical) band. Extremely low power ...


3

If the maximum amount of endpoints on any ZigBee device is 240, how could it send and recieve commands in large networks of more than 240 devices? Where are you getting this information from? It is not correct, the network address is 16b, so not limited to 240. Maybe you are getting confused with the Application EndPoint number which is 8b (with some ...


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