I'm trying to use Sparkfun's OBD-II-UART board to interface with a CAN network using a Raspberry pi 4. Upon connecting to sudo screen /dev/ttyAMA0 and when I send the commands, I'm not able to get any response from the OBD-II-UART board. Can anyone suggest why it is not communicating?
I need to send sensors (MPU9250) data from arduino to the Raspberry Pi 3, I'm thinking about using the ESP8266 Module in Arduino, but i can't find any help on how I will do this.
I'm thinking about creating a local web server using the ESP8266 and retrieve the data using a python script in the Raspberry Pi, but I am having trouble with the script for retrieve data from the server that is in another host.
you could create a simple rest api by adapting this tutorial for your usecase. then use the python requests libary on the raspberry pi to poll the ardunio every x secconds
I have a task to connect PROFIBUS (field bus technology by Siemens) to my Raspberry Pi. I need to make my Raspberry pi as a master and others devices as a slaves.
Let me know if you have any idea about how to make this connection. I am totally new in this topic and have no idea about this.
You might have a look at this project: https://bues.ch/cms/automation/profibus
When I understand it correctly, Profibus (Modbus) ist implemented by RS-485, that is not directly supported by the Raspberry Pi GPIOs.
You have to buy an extra shield or an USB to RS-485 Adapter.
There is also a library to send/receive data using modbus-protocol:
http://libmodbus.org/
I want to install MATLAB and Simulink support package for Raspberry Pi. I follow this link to do . I directly connect my laptop with Raspberry Pi using Ethernat cable.
But i didn't get output.
while installing i got error - "Could not detect a Raspberry Pi board on "Local Area Connection". Check your Ethernet connection to Raspberry Pi.
The FDX/LNK/100 LEDs on the Raspberry Pi board should be illuminated.
For network trouble-shooting instructions see http://www.mathworks.com">The MathWorks Web Site"
Can anyone help to solve this problem?
I have also experienced your same issue but after proceeding in this way I solved it.
Before you put the SD card on the Raspberry Pi you need:
power off the Pi
connect the Ethernet cable to the host computer
finally power on the Pi
In addition you may take a look at this troubleshooting guide.
Try the following steps.
1. Open cmd and execute 'ipconfig'
check for a network interface with '169.x.x.x' ip address
If there is one, you could access your Pi via IP 169.254.0.2
If there is none, check if your Ethernet port is enabled and no static IP is configured.
The above steps make sure that your Ethernet port is in proper state.
Repeat the hardware setup with direct connection in the network settings.
How can we do serial communication using the raspberry pi with a python script to send/receive data to my laptop? If yes can we use the RS232 cable to connect to the TX/RX ports on the raspberry pi directly? If yes, what pins must be used from the RS232 cable? It would be help full if anyone can post a example python script?
Since my first aim is to send/receive data to the laptop to/from the raspberry pi, i'm using a RS232 to USB cable at both end to connect to the laptop as well as the raspberry pi.
RS-232/RS-485 to PC and USB to PC
For RS-232
1) Download Putty.
2) Buy a Serial Port RS232 to TTL Converter Module and a RS-232 serial cable for PC.
3) Follow the steps in Connection to a microcontroller or other peripheral on this
link. Actually read the whole thing for better understanding.
4) Power your converter module with either 3.3V (pin 1) or 5.0V (pin 2), connect Rxd pin of the module to Rxd (pin 8) on Rpi and Txd pin to Txd (pin 10) on Rpi.
5) Connect your RS-232 (from PC) cable to the converter module
Now you are ready to do some coding in Python. But before that make sure that you have the library called serial for python to create the communication. You can easliy get it via terminal by typing sudo apt-get install python-serial. Also you will see the baudrate in the code is 7200. It could be less or more depending on the synchronization. Also make sure that baudrate should be same in putty and COM1, which is the port that RS-232 is connected to your PC. You can check and set it from device manager in Windows. By the way, timeout is the time gap between each message you are receiving.
In case you can't run the code from idle (that happens for some libraries), do it in terminal. For that go to the folder where you keep your python code and type python name.py.
import serial
import time
def readlineCR(port):
rv = ""
while True:
ch = port.read()
rv += ch
if ch == '\r' or ch == '':
return rv
port = serial.Serial("/dev/ttyAMA0", baudrate = 7200, timeout = 2)
while True:
rcv = readlıneCR(port)
port.write("I typed: " + repr(rcv))
print(rcv)
For USB serial to PC
You have two options
First, you can buy a USB dongle for RS-232/RS-485 so that you would not use GPIO pins. But it is better to get a USB hub for all mouse, keyboard and dongle.
Second and easier, you can buy a FTDI USB to TTL converter and use GPIOs to have a serial communication with Rpi. The code for this is exactly the same the one with above. Connection for this is easy.
Module -- Rpi
Txd -- > Txd
Rxd -- > Rxd
Gnd ---> Gnd
Are you trying to issue commands to the Raspberry Pi? (like a console?) I would suggest a plain jane 3.3V FTDI cable. You can get them from Digikey or Sparkfun. Note: the Raspberry Pi runs on 3.3V so you must be sure that anything you connect to it is running 3.3V or has a level shifter. See more information about level shifters here. (go down to the Logic voltage levels section)
First, you need to make sure that Raspbian has released the serial console. You can do that with the script located here.
If you're more interested with communicating with other devices then maybe the following suits you:
Do you have an Arduino? You can run a simple test by putting this sketch on your Arduino:
#define SERIAL_BAUD 115200
void setup() {
//Init serial connection
Serial.begin(SERIAL_BAUD);
Serial.setTimeout(1);
}
void loop() {
if ( Serial.available() ) {
byte type = Serial.read();
Serial.write(type);
}
}
And wire it up using the following diagram:
Note: make sure you don't connect a usb cable to the Arduino. It will be powered by the Raspberry Pi.
You can then install and run screen. Screen is a dead simple way of connecting to a serial port.
apt-get install screen
Then run the following:
screen /dev/ttyAMA0 115200
The screen will show up blank. But, when you start typing you will notice that the characters you're writing are getting looped back to your terminal.
Note: If the screen is still blank you should double check the connections (power led on the Arduino is a good thing to check).
When in doubt you can see my whole example here.
The Raspberry Pi's serial port uses 3.3v logic; RS232 uses 12v, so a level shifter would be needed to use those pins so you cannot use RS232 directly.
Serial interfacing in Python using the PySerial module (http://pyserial.sourceforge.net) it is pretty straightforward to send and recieve data. There are examples in the documentation, but essentially to send data:
import serial
port = serial.Serial(portname, baudrate, timeout)
port.write("message to send")
port.close()
It depends what you're doing with the data and what sort of data you're recieving to decide the best way to recieve data, but a very simple example:
import serial
port = serial.Serial(portname, baudrate, timeout)
data = port.read(numberofbytes)
print data
This simply waits until the number of bytes specified has been retrieved or the timeout value is reached.
You can use port.inWaiting() to return how many bytes are currently in the buffer.
you should install python library for serial drivers. you can not use rs232 directly, instead you can use a max232 chip in between rx(gpio15) tx(gpio 14) pins and your usb to serial converter. or you can use usb to ttl serial cable from adafruit. here is the link for setup : http://learn.adafruit.com/adafruits-raspberry-pi-lesson-5-using-a-console-cable/overview
Serial Communication in Raspberry pi.
There are plenty of options for serial communication
Use Visual GDB Plugin in visual studio and deploy code remotely in raspberry pi
and loop back the txd and rxd pins and check if the send message is received or not.
If you are familiar with java Install pi4j and in the example folder there is a sample program , compile and run using terminal. and check the output.
if you are connecting using RS232 and Max232 , please note that uses 3.3 volt not 5 or 12v. , it may burn your board.