i have a personnel project that consists on connecting a bracelet or a badge to a server.
And i wanna know how can i achieve this, is there any particular chips or small (very small) network cards that i can integrate in my bracelet/badge.
Related
I have a Jitsi instance that I would like to share with 50 people for an event. I will mute everyone to make sure that only one or two people are talking at the same time but I wonder if I need to ask people to cut the video too (which would be sad because seeing other people face would be fun).
I know that Jitsi works in peer to peer when only two people are connected but what about a larger room?
Does the server centralise all the video stream?
With more than two participants Jitsi Videobridge will take over (no peer to peer nor H264) and control video streams from clients to server to clients.
As far as I understand it works very much like a turn server.
It strongly depends on your hardware setup. If Jitsi is running on a dedicated machine it should be able to handle this.
On a virtual server on the other hand...
I am looking at a project that is trying to connect a number of IPad type devices, so each can pass information to the other members of this group.
For example, given six devices, if Dev1 moves to a new position, that position information should be propagated to Dev2-6. Similarly, if Dev2 moves, the information is passed to Dev1, Dev3-6.
It would seem to me that this might be doable by
Having a Message Broker with a MQTT topic to which all devices subscribe.
Writing the information to the broker
Then reading, or better still, pushing the data to other devices (perhaps using shadow devices).
Is this a reasonable approach? (I don't quite see how to write to the message broker).
Could binary data be sent?
Any ideas on how it would scale?
I'm trying to implementing tree topology with Cooja/contiky. Finding through examples i've not been able to find an a good example to find what i need.
In short :
I'd need to implementing a topology of this type(picture here under) with cooja end contiky, is there someone that could give me some advice?
Thanks in advance
I don't really use Contiki Operating System, I have only ever used TinyOS but a network topology such as the one you have should be easily achievable.
For TinyOS, the mote-to-mote radio tutorial HERE will show you how to two different sensor nodes can communicate with each other (a gateway is basically just a sensor node connected to a PC) and the mote-to-PC communication tutorial HERE will show you how a gateway node can forward information from itself to the PC it is connected to. When the network is running you basically have a Java application listening to USB port and receiving packets from gateway node. Once the packet has been received on the Java application then you can send it to an external network server.
It may sound difficult if you have never developed on TinyOS but what you want to do is very common and so there will be complete programs in the tutorial section of a typical TinyOS distribution showing you how to achieve most of the things you need you need to achieve. There should also be similar examples in Contiki.
I am writing an app that is suppose to work without a connection to mobile carrier and without local WiFi. Each device will act as transmitter, receiver and router.
My main challenge so far is that I cannot figure out how exactly MultipeerConnectivity works as documentation on MC is really limited. Apple denied revealing technical specification of MC claiming it's a proprietary network stack, so I have to rely on network sniffers and reverse-engineering which is not the quickest way to figure out how MC works.
Suppose I have 100 devices forming a mesh network in such way that each device is within the range of at least one other device and at maximum three other devices.
Is there any way to send a message from node A to node B that is not within the range of node A without the need to broadcast the message to all other nodes? I mean that message should be properly routed through all other nodes.
Does MC include a routing layer too or I have to write it myself?
From what I can see ad hoc delay tolerant wireless networks is still a hot subject in research.
These slides on ad hoc delay tolerant wireless network shed more light on the subject as it was a few years ago. And also this paper. Has Apple progressed it much with MC?
I cannot really see any way to send a message between nodes not directly connected to each other without flooding.
Correct?
The MCSession Reference states that
Sessions currently support up to 8 peers, including the local peer.
Also, the overview you cited says
In the discovery phase, your app uses a browser object […] to browse for nearby peers[.]
Moreover, the documentation on managing peers manually suggests that all peers in a session must be connected with each other to have them in a session.
This is suggesting that the framework only covers the communication between nearby devices, as in 'reachable by bluetooth or WiFi'. Naturally, those devices do not need complex routing, as they do communicate with each other and the benefit of the framework is simple multicasting between nearby devices, from a programmers' point of view.
As far as your question goes, this is about it - trivially, since all peers an a MCSession have links to each other - there is no routing needed.
This does however, allow you to construct a routing layer pretty easy.
Given your scenario, there will be multiple MCSessions with devices being part of at least one. All devices that are part of more than one MCSession do become routers and interconnect the MCSessions with each other.
The rest of the task should be straight forward; defining a namespace for addressing devices and implementing a routing protocol of your choice.
The old days of the internet, with unstable dialup connections, might be a plus factor for you as the routing protocols in place are rather stable in regards of link loss.
Here are two good starting points for you to make your choice of better fit:
Link state routing
Distance vector routing
I'm trying to find a way to take multiple mobile broadband connections, and bridge them together to expose one wifi access point.
I want to tether the phone's broadband, and multiplex the data.
How can this be achieved? Is there a router, that has multiple wifi's that can be used to connect to the phones?
Will I need to write a script to manage the data? Or is there something out there?
This is actually a little more complicated than it seems at first as you need to consider both ends of the connection.
You can combine multiple lower bandwidth connections as you suggest to provide an aggregated capacity at your WiFI access point, but you need to remember that the back end will still see multiple individual connections. So if you have a single server that you are trying to receive a single large stream from, it will see multiple smaller connections instead of a single large one.
You can get round this by adding some functionality on the server side to 'bind' or 'bond' the individual streams and make them appear as a single large connection to your server but you usually need a service from your ISP or some specialist 'bonding' provider to achieve this.
See the very good discussion and links in the answer below on Superuser for more information:
https://superuser.com/questions/660798/merging-two-incoming-broadband-lines-for-faster-internet