I have a sensor that uses multiple instances of the LwM2M Generic Sensor (3300) object. Sensor send a batch update of instances to Thingsboard LwM2M Server, but it doesn't show this report.
I test my sensor with the Leshan server and Leshan shows the list of instance batch update values which means the sensor is working properly.
should I configure Thingsboard to support lwM2M multiple instance objects?
I found the solution, for multiple instances objects, you have to tell Thingsboard instance ID at Device profiles->LwM2M Model->Add New Instance (Plus Buttom at end of sensor row)
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All this is done in the Cooja simulation.
I need to develop a project in which I have a mote (or many) that acts like a sensor and sends data to a server which does computations and publishes the results on a topic using MQTT.
In both cases I assign IPs to motes using the rpl-border-router example provided by Contiki-NG.
I can publish fake data created by the server and publish it through the border router via MQTT; I can create a tree to send the values from the sensor motes to the server using UDP and compute what The problem is that I can't connect the two.
I don't attach the code because I want to understand the structure that I should use to accomplish this and the general idea behind the solution you propose, if possible
I tried two configurations but none works, because I think I don't have the right structure.
These are the two settings:
one mote per functionality: 1 sensor (1) sending data via UDP to a server (2), this server is set as root using NETSTACK_ROUTING.root_start(), which should publish data through MQTT via the rpl-border-router (3). I think the error here is that the server is set as root, while the rpl-border-router should, but then how can I send data to the server for computations?
use the rpl-border-router (1) as server also, so it computes the outcomes and publishes through MQTT, receiving the values via UDP from sensor mote (2). The problem here is the synchronization between MQTT broker assignment and IPv6 assignments, since both require IP
Thank you
I am new to CAN communication and one of my tasks is to use a CANalyzer to learn what message IDs are being used for a product and what data is being sent/received.
The product has multiple nodes that can send/receive CAN messages. I know CAN messages are broadcasted to all the nodes, but the part I'm having a hard time determining is which node transmitted the message and which nodes received it.
So, for example, if I have 3 CAN nodes, is there a way I can determine that Node 1 sent the message and Node 2/3 are receiving the message?
Thank you in advance.
Generally, you can't know this by listening to the CAN bus alone. The same old story whenever someone asks about data on "CAN bus" is: what application layer protocol is it using? "CAN bus" doesn't tell you jack, it's just the specification physical and data link layers. The concept of identifying individual nodes does not exist on the data link layer, only on the application layer.
There's two possible ways for you to tell:
If you know the application layer used on top of the physical CAN bus and know that it uses node id, then you can tell which node that is sending what data by decoding the application-layer protocol.
On each node, you can sniff the Tx signal between the MCU and CAN transceiver with an oscilloscope. That one only goes active when a node is sending or ACK:ing. Most modern scopes has a CAN frame decoder feature, saving you the head ache of decoding the frames manually.
I am implementing a robotic system based on ROS. I have different nodes which send data multiple times per second. However, I don't need that. I want to send the robot state only when it is at a new location. What technique of ROS do you suggest to use?
Dependent on your requirements, you can either use the ROS Services or the Parameter Server.
ROS Service: The publish / subscribe model is a very flexible
communication paradigm, but its many-to-many one-way transport is not
appropriate for RPC request / reply interactions, which are often
required in a distributed system. Request / reply is done via a
Service, which is defined by a pair of messages: one for the request
and one for the reply.
Parameter Server: A parameter server is a shared, multi-variate dictionary that is accessible via network APIs. Nodes use this server
to store and retrieve parameters at runtime. As it is not designed for
high-performance, it is best used for static, non-binary data such as
configuration parameters.
I have a relatively simple switch that sends data whenever the button is pressed (either 1 or 0). The message protocol it uses is MQTT. It is connected to Mosquitto via Wi-Fi and successfully sends data to it (i am able to see it using mosquitto_sub -v -t "#". However, I would like to be able to send this data to Orion Context Broker and then receive it using REST commands and store it using Fiware-Cygnus afterwards.
the topic that sensor publishes messages to is tt/sergo/demo/sw
the name of the sensor presented in mosquitto_sub when sensor is first connected: DMS-A01
the IP - address of sensor: 192.168.0.108
I have installed Iot-Agent UL, which is working, but I don't know how to make it listen to the specific sensor that sends data to Mosquitto.
I read the manuals but either missed something or did not find the solution to my problem.
I tried using the manual below, but could not apply it to my problem.
Connecting "thing" to Fiware
Thank you in advance, stack overflow community.
Before sending measures you need to do a provision operation for the device using the IOTA-UL API. That provision operation "creates" the device in the IOTA-UL and map it with the corresponding entity at CB. Then, you can start sending measures using MQTT.
You can have a look to this piece of documentation for more detail.
I'm trying to understanding how a broadcastHashJoin is executed.
I know that the little table is send broadcast to all node, but next the result is sent back to the driver?
I'm using the spark ui to undestand how network traffic is managed but i don't get relevant result and the driver result always empty:
Why i can't see traffic to driver?
Relation which is to be broadcasted is collected to the driver
Collected relation is hashed locally
Hashed relation is used to create a broadcast variable
Broadcasted relation is used to compute join in parallel
Missing data from the driver you see most likely correspond to hashing part which is not executed inside job and doesn't create useful metrics.