What are the properties of a wireless sensor node ?
From Omnet++ manual i came to know that
simple wirelessnode
{
gates:
input radioIn;
parameters:
...........
}
Though the node have only input gate , how it sending data to other node?
if the node is wireless how the sensor node connected ?
How to define a region around a wireless sensor node for reach another node in range?
Thanks
For sending, you can think with a DODAG : take a tree, put the root as the gate. The gate gathers the data of its children, each of those children gathring themselves the data of their children ... the leaves are the nodes that need the more hops to be reached from the root.
Here you would need, among others : the power of the transmitting, the power of the receiving chip (so that if the sending node is too far away then the receiving node won't catch its frame for example, as pointed by user4786271), a protocol to route them (so that if a node has 2 other nodes in range of rank n-1, to know which one it will use).
Try to dig into some open source WSN simulators implementing protocols, you could get a lot of info. For example : https://bitbucket.org/6tisch/simulator/src
To answer your exact question, there is no such thing like "general properties" for a given module when designing a protocol.
Usually the decision of the module properties that you are going to use, is strongly related to what that node is supposed to do as part of your protocol.
If your node is never going to communicate, there is no point in adding a gate to it.
Though the node have only input gate , how it sending data to other
node?
You don't have to strictly adhere to the design that you have seen. Maybe in that case the nodes only need to receive messages. In your case you might want to define an output gate.
if the node is wireless how the sensor node connected ?
Do not view the gates as physical entities, but rather as interfaces which are capable of communicating through links. Do you see a cable link between your mobile phone and the basestation? Probably not, because they are connected through a wireless link. So your mobile phone has an interface for wireless link. See where I am going? In your case you will need a gate with wireless link.
How to define a region around a wireless sensor node for reach another
node in range?
Hmm, based on your propagation model the received signal power will depend on the distance, right? You can check the received power for the MAC frame and dismiss it if it is below a given threshold.
Or, if you work on the application layer -- which you don't -- you can embed location information in your packets and then perform pairwise distance comparison to decide packets from which sender to consider or drop.
Related
Using PyVISA on an Ubuntu-operating computer (Ubuntu 20.04.5 LTS), I would like to interact with a VNA machine (E8361A, Agilent technologies) in the following way,
1- Connect to the VNA through a port.
2- Send a signal to VNA to start S-parameter measurements within a specified frequency range at specified number of points.
3- Send a signal to VNA to stop S-parameter measurement, fetch the S-parameter data, transfer the data to the PC and save the data.
Q1: Which VNA port do you recommend to use (GPIB, Ethernet or USB), and why?
Q2: Depending on the VNA port, what hardware is required to connect the PC to the VNA?
Q3: Is there a way to adjust the power level of the VNA stimulus signal? If yes, how to inquire the maximum and minimum power levels? Can the power level be adjusted continuously or only discrete power levels are avilable? (Basically, how to control VNA's internal amplifiers/attenuators?
Q4: Can you please share a sample Python code which uses PyVISA to save S-paramater data in the fashion described in steps 1--3?
Q5: Does trigger port have to do anything with sending signals to the VNA to start and stop measurements?
Since I am not working on ubuntu, nor I have the machine you have I can't say much. I am also rather new to pyVISA so my knowledge there is also limited, but since no one else answered:
Q1. I use a usb port since it is the only one I have, but the faster the better i would assume. There seems to me to be more GPIB examples found on the internet so maybe it is an easier starting point.
Q2. As with others (like mine) I would assume only a cable.
Q3. Yes, see the [write][1] function. It may look something like this:
# Connect PNA to computer using resource_manager etc., it is well documented
PNA.Write(f':SOUR{channel_num}:POW:LEV:IMM:AMPL {source_level},"{source_name}"')
For the maximum and minimum values see the documentation of your hardware.
Q4. Your 'Send a signal' I don't know how to do. But you could just while-loop and send-and-recieve in each instance until you want it to stop. Here is an example from keysight:
https://edadocs.software.keysight.com/kkbopen/a-python-programming-example-for-the-pna-family-vnas-sweep-time-various-point-counts-no-error-correction-577935568.html
Q5. I don't know.
EDIT: On Q4: I found this [link][2] , which would what I believe result in
PNA.write('SENS:SWE:MODE CONT') for continous sweeping and
PNA.write('SENS:SWE:MODE SING') for single sweeping.
In this case change from CONT to SING when appropriate and it should stop sweeping.
[1]: https://pyvisa.readthedocs.io/en/latest/_modules/pyvisa/resources/messagebased.html#MessageBasedResource.write
[2]: https://rfmw.em.keysight.com/wireless/helpfiles/89600b/webhelp/Subsystems/gui/content/mnu_control_sweep.htm
I want to implement a P2P protocol in C for personal education purposes.
What would be the protocol with the shortest specification that is still used today?
I have already implemented a web and IRC client and server.
I agree with Mark, that point to point over a serial link would be a good exercise.
In particular, I would recommend the following programme of stuff...
Implement basic transmission over a "Serial Port" (using RS-232 if you have some Arduinos/embedded processors lying around, or using a null modem emulator if you don't (see com0com on Windows, or this on linux/mac).
I.e. send lower case letters from A->B, and echo them back as upper case from B->A
Implement SLIP as a way to reliably frame messages
i.e. you can send any string (e.g. "hello") and it is returned in upper case with "WORLD" appended ("HELLOWORLD").
Implement the "Read Multiple Holding Registers" and "Write Multiple Holding Registers" part of the Modbus protocol, using SLIP to frame the messages.
I.e. you have one follower (slave) device, and one leader (master) device. The follower has 10 bytes of memory that are exposed over modbus with the initial value "helloworld".
Just hard-code the follower / leader device Ids for now.
The leader reads the value, and then sets it to be "worldhello".
At the end of this you would start to have an understanding of the roles of network layers, ie:
The physical layer - Serial/RS-232
A "link layer" of sorts - SLIP
An "application" layer - Modbus
Serial. The answer is serial. You're not going to get any leaner than simple RX/TX communication but you'll lack a lot of convenience methods. If you want to explore more than simple bidirectional comms, I2C or modbus open up a lot of options.
I'm dealing with the following challenge. In my system, there are two devices. Tags and anchors. Tags have BLE module with the transmit power 0dBm and not Long Range feature (BLE 4.0). Anchors have BLE module with transmit power over 8dBm and Long range feature (BLE 5.0).
I want tags to only receive some commands. Bi-directional communication is not necessary. This way, I can utilize the transmit power of anchor (8dBm) and thus quite bigger range, if tag with 0dBm is only receiving.
I read something about Observer/Broadcaster principle, where connecting is not necessary. But somehow devices have to agree on what frequencies should they hop on, the step and so on.
I'm asking, is it possible for device to only receive commands without previous negotiation with the sender?
Thank you very much for help. I'm beginning with BLE standard and there is a lot to learn.
Yes, it is possible to send data via adverts/scanning only. This way, there's no connection that needs to be established, and therefore no connection parameter negotiation takes place. As for the frequency hopping agreement - this happens via the baseband (in other words you will not deal with this in the software yourself) and is generally not applicable for advertising/scanning (these happen on 3 frequency channels only and therefore it is likely that the observer will catch what the broadcaster is broadcasting).
However, keep in mind that because you are broadcasting/advertising the data as opposed to directly sending it, that data can be received by any observing/scanning BLE devices which is not desired for safety/security/privacy purposes.
For more information on BLE communication, I recommend the links below:-
Getting Started with Bluetooth Low Energy
Is it Possible to Send Data with BLE Broadcast Mode
I am currently working on a project which aim to detect Bluetooth and decode Bluetooth packets (I use a Hack RF One to make the detection). I have made a Gnuradio Flowgraph in order to demodulate Bluetooth signal and I am trying to decode visualy the packets by searching a Bluetooth frame on a binary file.
Unfortunately, I didn't succeed to recover a clear view of the Bluetooth signal. To be precise, I am pretty sure that I detect Bluetooth on my sinks but when sending this to a Clock Recovery + Binary Slicer blocks, I am unable to recover interresting data in the binary file (especially the MAC adress of the sending device, which is part of the a Bluetooth packet). Moreover, I would like to know what type of network layer (physical, transport, baseband...) is intercepted in this type of process. In my case, I aim to intercept baseband layer packets.
Additionaly, I am interrested in knowing how to use the gr-bluetooth because I can't find a lot of documentation concerning this block. I think this can be interresting for the development of my project.
Could you please, give me your view, opinion about this problem ? I am stucked at this stage without knowing the exact origin of my issue. (Here is my flowgraph GnuRadio_Flowgraph and a screenshot of one of my Bluetooth detection Detected signal at 2.402GHz).
Thank you very much,
You probably need an ubertooth instead https://www.sparkfun.com/products/10573
I read that the bluetooth frequency skipping is spread wider than the HackRF can read, so at-best, you're going to miss 75% of frames if you only have one hackrf connected.
I'm using a Virtex 5 FPGA and want to have a few +5/0 I/O pins to communicate with a microcontroller. The only peripherials I've used on the board so far are pushbuttons and switches and no one I've asked seems to know the simplest way to do this I/O. I've looked around the board specification but haven't found any simple way of doing it. I would appreciate any advice you might have.
This is not an easy thing to do. If you don't have the schematic of the board, then you need to get volt meter with some fine pitch probes and reverse engineer the board.
It is pretty easy if you have 2 boards, with one board it can be really hard since the BGA signals may not be connected to a via and therefore not available on the bottom of the board, and even if they are, then you don't know exactly which pin they are connected to. But with some luck, you can find them since the VIA can only be connected to 4 possible pins surrounding it!
The first thing you need to do is to identify your chip, find the BGA print of the IC from Xilin'x web site.
If your board has some buttons already, then if you are lucky, those signals may be routed to the pins of the FPGA that are available on the bottom of your board. Here are the things you need to do:
Make sure you have good ESD protection to perform these test
Put your voltmeter into 'buzzer' mode
Check the pins of your connector and find out how it is connected, see if there is a pull-up and/or pull-down resistors on the board
when you find the 'active' pin of your connector, start connecting the other probe to the VIAs one by one
When you hear a buzz, make a note of the position (guess or measure the distance between the side of t he IC and the location of the via)
Identify the 4 possible pins that the signal can be connected to
Write a code to get all those 4 signals and connect them to ChipScope
In Chip Scope, capture all 4 signals and see which one is the one with the right connection!
alternative, you can create a design with inputs only, capture all the inputs and put them into a memory block and create a trigger logic to capture all the signals whenever any of the inputs changes, after lots of work and analysis, you will find the correct pins.
Anyway, these are just crazy ideas since this is a really difficult thing to do without having the PCB info of the board.
Good luck with your hacking.