Hi I have XBee RF mode S2C which does not have internal storage to run micropython. So I need to get data from KY-001 sensor connected its iolines. With python library I didnt get anything just get_adc_value(ioline) function which seems doesnt do anything. I need to check sensor in local device for now .After I gonna use same solve to remote devices (I only use Python XBee library). Or exactly can I use Xbee iolines directly to get data from sensor without external MCU?
I don't think you'll be able to interface to this 1-Wire sensor, it's intended for a microprocessor that can handle timing requirements and uses a tristate I/O line (IIRC).
You should be looking at temperature sensors with an analog voltage output (like this TMP36) that you can tie to one of the analog inputs of the XBee, and then read that input with a remote ATIS for a single sample or ATIR for periodic sampling.
Related
I am creating a mobile robot at my work using a Raspberry 3b+ as microcontroller. To determine the robot displacement I am using a motor with encoder sensors.
The problem is: I need to read the Encoder channel changing to count the pulses and also determine the direction. To do this I was using a callback to read the pulses edge, but the callback it is not fast enough to get all the edges and I lost information because of that.
A solution that I could think it was to use a C program using the WiringPi library to read the encoder, I tested it and it worked. Now I need to use this C program in my Python project.
Any idea in how I can do that?
I am currently trying to implement simple communication between an I/O module as a CanOpen slave and my computer(Python script). The I/O module is connected to my computer with a PEAK USB-CAN adapter.
My goal would be to read or write the inputs/outputs. Is this even possible with the hardware, since I don't have a real "master" from that point of view?
Unfortunately I don't know what else I have to do to be able to communicate correctly with my I/O module.
import canopen
import time
network = canopen.Network()
network.connect(bustype='pcan', channel='PCAN_USBBUS1', bitrate=500000)
#add node and DCF File
IO_module = network.add_node(1, 'path to my DIO.DCF')
network.add_node(IO_module)
IO_module.nmt.state = 'RESET COMMUNICATION' # 000h 82 01
print(IO_module.nmt.state)
time.sleep(5)
IO_module.nmt.state = 'OPERATIONAL'
print(IO_module.nmt.state)
for node_id in network:
print(network[node_id])
IO_module.load_configuration()
i see some kind of communication in my console with timeout errors
INITIALISING
OPERATIONAL
<canopen.node.remote.RemoteNode object at 0x000002A023493A30>
Transfer aborted by client with code 0x05040000
No SDO response received
Transfer aborted by client with code 0x05040000
No SDO response received
Any advices ?
I can't get any further with the documentation alone
https://canopen.readthedocs.io/en/latest/
thank you
The good news is, you probably have all the required hardware. You are doing the "master" part from Python, that's fine. (The CAN bus isn't really master/slave, just broadcast. CANopen can be master/slave sometimes, but it's still all broadcast messages among equals on the same bus.)
You haven't provided information about your device, but I would start checking at a lower level.
Do you even have the CAN-Bus wired up correctly, and if so, what did you do to verify it? (Most common mistake: CAN-Bus not terminated with two 120ohm resistors. Though you usually can get away with just one instead of two.) And have you verified that you are using the correct baud rate?
The library docu example suggests to wait for the heartbeat with node.nmt.wait_for_heartbeat(). Why are you using a sleep instead? If there is no heartbeat, you don't need to continue. (Unless the device docu says that it doesn't implement NMT heartbeat - would be unusual.)
I certainly wouldn't try to go ahead with SDOs if you cannot confirm a NMT heartbeat. Also, some devices don't implement SDOs but only PDOs.
Try sniffing the CAN bus at a lower level (e.g. not PDOs/SDOs but just print the raw messages received - from Python, or with a separate application - e.g. candump on Linux.) Try getting statistics of the CAN "network" interface (on Linux, e.g. ifconfig). If everything is okay, the adapter should be in state "ERROR-ACTIVE", and you should see the frame counter increase for frames you've sent via Python.
How can I set HIGH or LOW to a usb port connections using Python.
This could be used in come custom usb device.
For Example,
Consider I have a LED connected to the usb port(DATA Line) .
Now through the code I want to blink it or control it.
Now this can be easily achieved by using any micro controller, Arduino, Raspberry Pi
But I want to achieve this with with a normal computer and python.
[EDIT]
Can I achieve this by making a C or C++ API and make a wrapper to use it in Python. Is yes then what will be the best way to achieve it?
NOTE :
My main objective isn't just blinking some LED. I just gave it as an example.
I want to be able to directly control the USB ports.
Quoting : https://www.cmd-ltd.com/advice-centre/usb-chargers-and-power-modules/usb-and-power-module-product-help/usb-data-transfer-guide/#:~:text=How%20is%20data%20sent%20across,amounts%20known%20as%20'packets'.
Within the standard USB 2.0 connector you can see four metal strips. The outer two strips are the positive and ground of the power supply. The two central strips are dedicated to carrying data.
With the newer USB 3.0 connector, the data transfer speed is increased by the addition of extra data-carrying strips; four extra signalling wires help USB 3.0 achieve its super speed.
I want to set the values of the Data pins.
By my saying HIGH LOW please don't misunderstand that I want to set the value to +5V and GND. But I mean to control its value directly via my code without any external driver present in the computer.
I mentioned HIGH LOW to just make the language simple and so that it is easier to understand.
Controlling components like LEDs from devices like Arduino and Raspberry Pi are done using GPIO pins. In contrast, USB is designed for data transfer and not for maintaining more constant high or low signals like GPIO. It also consumes different voltage and current levels than GPIO pins and could potentially damage components meant for GPIO.
However, you can get USB to GPIO adapters for this purpose (see here for an example discussion on these options).
In terms of Python, you can use packages such as PyUSB or the libusb Python wrapper to control/transfer data/communicate with USB devices (such as the USB to GPIO adapters). The companies providing the adapters might also have designed their own easy-to-use Python package to wrap around a lower-level driver (probably written in C). See this USB controlled LED device as an example with its own Python driver. The drivers are just software programs that take in relatively simple commands from the user for what they want a device to do. They then encapsulate the lower-level complexities required for following a protocol to communicate the user's intention to the USB device and controlling the USB port at the lowest possible software level.
You cannot achieve that for several reasons:
The USB port has its own protocol of connection. Data is transmitted in packets with starting and ending bits. The negotiation and handshake process is done in the hardware layer between microchips. This process also selects the communication speed in the bidirectional data line. You have to direct access to the pin (like GPIO) to turn LEDs ON and Off or create your own connection protocol. This cannot be done in USB.
There are also voltage and current limitations. The data line is not +5 and GND. The data line is 2.8v for D+ and 0.3v for D- and both with respect to the GND. The data is transmitted and received differentially (D+ with respect to D-) and they are not compared with the GND for 1s and 0s.
The button line is you have no direct control over USB.
I'm building a project where I have multiple Arduinos, each having a temperature sensor and a [input wireless transmission method here].
This data would be received by a controller, a Raspberry pi, which would act as the server: call to Arduino, collect the data, and store it. This data would be accessible to a Mobile App, but this is out of the scope of the question.
Requirements:
Arduinos must read simple raw data (in this case, the temperature reading from the sensor) and make it accessible to the Raspberry pi, which would make calls to each Arduino board (from 1 sec to 1 min time frame).
Arduino side must have a low energy consumption, as it would be powered by a small battery;
Data transmission on Arduino end must be as cheap as possible and work in low temperatures (around -5 degrees Celsius). They would be stored be inside a freezer, so temperature and a thick-ish metal layer are obstacles to overcome.
Question: is Bluetooth a viable transmission method? Is it possible to pair multiple Arduinos to one Raspberry pi at a single time?
If Bluetooth isn't any good, what is? Correct me if I'm wrong, but Wifi is a high energy consumption solution.
OBS: if needed, the Raspberry Pi board could be swapped for an Arduino one.
Cheap, low power and tiny row data?
I suggest you to use nRF 2.4GHz transceiver module. It may look some old school way but will meet with your requirements.
It consumes 0.9 nA while deep-sleep mode and ~10mA for just transmission.
Also it is easy to program and due to its connectionless arch, you will not need to know states about the connection. Just being sure to send and received successfully, suggest you to add deviceId and succeed flag in your raw requests.
Here is vendor site :
http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24L01
Good luck!
My issue is to make a serial communication between raspberry pi and another hardware. The recommended connection for this hardware is as shown on the manual, I have to connect, RX, TX, GND, RS, and CS.
But on raspberry pi we have only RX, TX so I connected RX and TX and The GNG of Pi to this hardware.
I modified Pi's parameters as shown on the link : here
Then I maked a simple python program that initialize the communication, and send data.
Here is the code :
import serial,os
port=serial.Serial("/dev/ttyAMA0",baudrate=9600)
print ('port is ok')
port.write('Command')
rcv=port.read(10)
print rcv
after running this code on pi, I got ('port is ok'), But the problem is that this hardware don't respond correctly to the command, and as respoce it gave me normally OK, but I got some extra caracter( non readable).
Is that a problem of encoding? Can some one help about this?
You need to check the baud rate on the other hardware
or make sure that the length of the received message = to the printed message.
In a serial communication, there are two important things to be careful :
The two devices have to work with the same baudrate IF the link is bidirectional.
When writing data on serial, you have to flush data just after the write().
refer to here for it.
In a lot of case, flush isn't needed, but when two different devices have to communicate, it could unlock the comm'.
If it's not efficient, try to set up your other device with the same conf (no flow control, etc)