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20

A general process of microcontroller selection. Sum up your requirements towards the microcontroller. For example in this case: 1 hardware timer, to measure time between trigger and echo pulses. 2 GPIO pins to interface the sensor Echo and Trigger pins. Possibly UART to interface the RF communication module. 1 ADC input to monitor the battery voltage. You ...


13

There are a few things that really distinguish Z-Wave and ZigBee from each other. Frequency The first (as Eirik M noted) is the frequency on which they operate. Z-Wave operates within the 915 MHz ISM band. This gives it reasonable penetration of building materials (better than Wi-Fi) and good overall distance. The fact that few other household devices ...


11

If you have no intention of communicating with a device that doesn't use ZigBee, you probably wouldn't need a hub. You might be interested in 'Why do I need hubs for some devices when automating my home?'—one of the main reasons the hub is needed at all is so that a ZigBee device can communicate with your Wi-Fi router and connect to the Internet. If you don'...


10

Xiaomi sensors can be paired with SmartThings, according to this blog: Log in to the SmartThings IDE Create a new device handler using the sources provided on GitHub Click 'My Location', then 'Events' On the app, go to 'My Home' > 'Things' > 'Add a Thing' Push the button on each sensor for ~5 seconds to enable pairing mode Look for an entry named 'Catchall' ...


9

I think there is mainly one thing you should care about: Is the ZigBee solution 2.4 GHz or 868/908 MHz? The 2.4 GHz penetrates less then ~900 MHz through walls, and the 2.4 GHz shares the spectrum with Wifi, Bluetooth, the microwave oven, to mention a few. The Z-Wave is only using the 900 MHz band. Both solutions have complete network stacks, but the are ...


8

The lightwaveRF lighting protocol is simple OOK at 433 Mhz, I think. It's documented, so you could use them. Maybe a little bit more expensive than other options though. Here is an Arduino/Raspberry Pi library. This is of course a solution with zero authentication or encryption, which ought to make it less attractive. There also seem to be some WiFi ...


8

Your challenge is handling the throughput demands with channel contention. Your devices are all close enough that you need to assume they are all potential interferers to each other so you will need to use a protocol that is robust to this - probably using some sort of coordination between devices to ensure they all take a fair slice of the channel. You ...


7

Latency vs Rate a low-latency (10 Hz) type of IoT application This is a conceptual error. Latency and Rate are largely independent. You could have a system which recorded thousands of readings per second, stored them on an SD card, and once a month someone visits the remote site, extracts the card, and mails it to you - that system would have a high ...


7

That is a very good question and actually my current research topic. I try to give an adequate but concise answer¹. I will focus my answers to networks based on the IEEE 802.15.4 standard (Zigbee and 6LoWPAN both use it as physical and data link layer) as well as networks where most traffic goes through a common gateway. Most arguments also hold for peer-to-...


7

You say you built a Zigbee network using Digimesh protocol. The thing is that this is an impossibility: Zigbee and Digimesh are competing solutions for mesh network, not something you use together. See this link: Digimesh manufacturer explains the difference between Zigbee and Digimesh Digimesh uses Sleep Modes 7 and 8 whereas Zigbee uses 4 and 5. Have you ...


7

It is actually possible to allow for sleeping nodes without the need for time synchronization. The basic idea is to send a message multiple times until the node finally wakes up. There is of course a lot of room for clever optimization, so there are hundreds of MAC layer approaches based on this idea. But since your question specifically asks for MAC layers,...


7

If you're not married to Zigbee's flavor of 802.15.4, you should take a look at Helium's end-to-end wireless capabilities. (I work for them - naturally.) Our module uses the same PHY but pushes most of the MAC trickiness into the cloud. And there is no meshing (which tends to drain batteries faster and complicate security). Instead it's a star-of-stars ...


7

As comments indicate there is apparently indeed a licensing and certification process involved that might indicate where some part of the price stems from. Though well known in the automation industry, ZigBee is expensive. The protocol is computationally intense and the memory footprint is large. The ZigBee Alliance requires all implementers to join ...


7

There are a number of 802.15.4 solutions which are not Zigbee, and cost less. See this article: "What’s The Difference Between IEEE 802.15.4 And ZigBee Wireless?" As I understand it, to use the label "Zigbee" you must comply with certain requirements and guarantee interoperability with other Zigbee devices. Otherwise it would be "Zigbee-like" or some such. ...


6

You could, but you'd need a radio transceiver with compatible frequency range, modulation, and data rate. Typically radios with those capabilities are either sold as Zigbee radios, or for the underlying 802.15.4 layer. Sometimes they can do some additional custom modes of communication as well (though often available software stacks force you to pick a ...


6

There isn't any official support, but a user in the SmartThings Community forum has created some device types that should work with the motion sensor and on/off switch here: I have created a simple device type for the Xiaomi Smart Button that can be found various places for around $10. Other users have stated that this device loses connectivity to the hub ...


6

Z-Wave is a mesh networking technology commonly used for home automation that allows many different brands of products to interoperate with each other very easily. However, it is a patented proprietary protocol that requires a licensed Z-Wave chip, which are not generally available to the hobbyist at affordable rates. To communicate, Z-Wave devices must ...


6

Ubisys G1 seems to be a device (the only one?) that does this. A brief description from the product page, for reference: Our gateway links your ubisys smart home to the outside world. It establishes a link via the internet connecting the ubisys smart home App on your mobile end device with the ubisys smart home components installed in your home. Connect ...


6

The Logitech Harmony Hub is a smart hub that can control devices via infrared (like your TV remote), and is compatible with Alexa. It doesn't work via ZigBee, though — it connects via Wi-Fi to your Echo instead. You can see if it's compatible with your device on the compatibility page; as of writing, Logitech claim that the hub is compatible with over 270,...


6

I had the same issue when scanning for zigbee packets with Ikea Tradfri. The solution on my end I found by chance when switching the scanning channel from 11 to 15. Apparently the commissioning process switches channels during ZLL touchlink. My Ikea bulb responded to the "Scan Request" with "Scan Response" on channel 15, whereas all the other traffic ...


5

It is important to identify whether the problem is : Devices or network deployment Devices or network configuration. Devices Hardware (or firmware versions) Environment Security configuration The paths to take here are too diverse so you need to narrow down the cases. Sometimes a photo helps to spot the possible deployment issues. Here are some ideas:...


5

If you want to bridge from WiFi (Google and OnHub) to ZigBee, then you will need a device which handles the bridging function. This doesn't have to be a proprietary bridge, it could be as simple as an Arduino with TCP-IP on one side, and ZigBee on the other (or a Raspberry Pi type device). Even if you construct this function yourself, it would be still ...


5

Looking at ease of programming and low cost, I would probably start with some kind of Arduino module (or low-cost clone). Code for your ultrasonic sensor already exists, as does example code for ZigBee, for example using the Digi XBee modules. On the latter, you connect the XBee to a serial port, and after making the connection with the venerable old "AT" ...


5

As is often the case, it depends. There are many factors to consider, and a lot of options available to cover the many different use cases around. Range DigiKey suggest that you can expect the following ranges for common IoT protocols in an unobstructed environment with little interference: 5 GHz Wi-Fi: 50 m ZigBee/RF4CE: 100 m Bluetooth low energy: 100 m 2....


5

From what I'm reading you need bridges for specific devices, unless they support Z-Wave or Zigbee (may well be wrong on this...). In general, you need a "bridge" for everything - including Z-Wave and ZigBee. A bridge may be as simple as a USB dongle and some software, or it may be a stand-alone box, but there must be something to handle the radio and ...


5

It's unclear from your post which link key you are using. If it is the standard ZigBeeAlliance09 TC link key referenced in the post, then it will likely not work since Tradfri uses ZigBee Light Link. ZLL uses a different link key to the ZigBee Home Automation / ZigBee 3.0 well known shared key and The ZLL master key is not publicly available (although there ...


4

I would suggest painless mesh or easy mesh. Their Github pages (on the links) say specifically that they are for esp8266 and thus they are very cost effective.


4

If you consider that the internet is a mesh network of sorts, you should see your answer in the broadest terms. Asking is a specific mesh network has any scalability issues is slightly different. There is plenty of scope to architect a modified network protocol to address a specific implementation, with the right sort of optimisations. At some point, you ...


4

From what I've found, it seems that some implementations (e.g. TI's Z-STACK) recommend refreshing the routing table every so often to avoid 'dead' nodes: Yes, I waited 5 to 10 minutes. What is "some time"? I have seen cases where it takes a few minutes to recover. For example, if I cycle power on the gateway, it takes maybe a minute or two for the ...


4

As a software guy—and a protocol stack guy at that—I tend to look differently at this than you might. To me, these protocols are "low level" stuff (layer 1 & 2 of the OSI 7 layer model). I don't particularly care about power consumption, unless the device is battery or solar powered. In my professional life, I can leave decisions about hardware, which ,...


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