I have an Arduino with a shield communicating with a motor controller over RS-232/Serial. During communications when I receive a response from the motor controller there are random characters / irregular responses.
The commands and responses are simple ASCII strings.
I have no problem communicating over serial between my PC and the arduino, and no problem connecting over serial between my PC and the motor controller, but together these two don't want to get along. Can anyone think of a reason why this would be the case?
Same baud rate (9600), standard settings: 8 bits, 1 stop bit no parity on all devices.
On the Arduino I'm using SoftwareSerial to communicate with the motor controller and the Serial Monitor to enter commands.
Any ideas?
SoftwareSerial is very susceptible to interrupts from other sources. If pins 8&9 are available, you should use AltSoftSerial. If not, and the motor controller sends plain text responses, you should use a library I posted on github, NeoSWSerial.
Related
I'm trying to write a simple code that sends a string to an xbee and one that sends the string back, I was able to do this with XCTU via console, but I want my arduino to send the string.
I was able to use a simple code that read my output from the serial monitor and sends it to an xbee connected via usb adapter, the problem is that I now wrote the code so it sends a predefined string like in the screenshot, but when I write into the monitor it still sends whatever I wrote instead of the static string. I'm also unable to read what I type into the xbee console from XCTU.
I'd love any assistance in this, I've tried uploading and resetting everything to no avail.
Screenshot of problem with the current code of the arduino on the left
You said you were using an Arduino to try to communicate with your XBee Zigbee module.
One thing you have to check is the connection between the TX and RX signals on the Arduino side and on the XBee Zigbee side.
I've helped someone on another forum who used this Seed Studio XBee shield :
If you look at the schematics of this shield, the XBee 'DOut' signal (Tx) is wired to the XB_TX line which can be connected to any of the AJ2 pin with a jumper.
Now on the Arduino side :
On this extract of the Arduino schematics, we can see that the ATMEGA UART has it's RX signal connected to pin 2 of the CPU which is wired to the IOL (AJ2) pin 0.
So, that means that on this shield, the jumper have to be placed between XB_TX and pin 0 of AJ2 to connect the XBee transmission signal (output) to the ATMEGA reception signal (input) [and also XB_RX have to be connected pin 1 of AJ2].
As you didn't mention what kind of shield you were using, you have to double check this point which is a common issue when using serial communication.
In a general way, ALWAYS connect 1 output to N input (except open-drain or open-collector outputs which can be connected together to make a wired OR but which finally have to be connected to N inputs)
Hope this helps
Best regards
From what I can tell on the documentation Xbee "hijacks" the serial system. Instead try blinking an LED to confirm data is being received and sent.
documentation
I recently bought an Arduino UNO to read the data outputted by my Smart Meter. The meter uses serial communication and I would like to see the values being outputted on my laptop screen. I figured I would need to use the SoftwareSerial library to read the incoming data and print that data on my screen using the hardware serial and the Serial Monitor in the Arduino IDE. To become familiar with (software) serial communication on the Arduino, I reviewed the documentation of the SoftwareSerial library. Problem is, I can't get the most basic example to work and I have been stuck on this for quite a while now. The example code is below, the example can be found here
#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); // RX, TX
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(57600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
Serial.println("Goodnight moon!");
// set the data rate for the SoftwareSerial port
mySerial.begin(4800);
mySerial.println("Hello, world?");
}
void loop() { // run over and over
if (mySerial.available()) {
Serial.write(mySerial.read());
}
if (Serial.available()) {
mySerial.write(Serial.read());
}
}
As far as I understand this, the following should happen:
- Type text in Serial Monitor window.
- Serial.read() reads this data and writes it to the Software Serial.
- The Software Serial reads this data and writes it back to Serial.
- That which was written appears on the screen.
But whatever I try, nothing happens. Among things I tried to following:
- Change the baud rate for both software and hardware serial (9600 for instance).
- Tried a different SoftwareSerial library (AltSoftSerial).
- Tried different RX and TX pins for SoftwareSerial.
- Instead of Serial.write(mySerial.read());, store the result in a char first.
I'm probably missing something obvious. I would be grateful to anyone who could shed some light on this or offer an alternative way for me to read the data from my Smart Meter.
Edit
I had no wiring, because the example specified "There is no circuit for this example". I tried all three options suggested by #slash-dev, but none had the expected behaviour:
SoftwareSerial with wires connecting pin 1 to pin 10 and pin 0 to pin 11. It prints strange characters:
Goodnight moon!
Ùniÿhtÿmoÿn!ÿ
nihtmoÿttt
AltSoftSerial with wires connecting 1-8 and 0-9. First prints Goodnight moon! and then it keeps printing Ô당¥�¡Ñ�moon!.
NeoSWSerial with wires connecting 1-10 and 0-11. Same as AltSoftSerial but keeps printing Ôë‹–+ë¡Ñ�j½½¹…j.
The baud rates must be the same on Serial and mySerial.
And you don't describe the connections, so I have to ask: Did you connect a wire from pin 1 (Serial transmit) to pin 10 (mySerial receive), and another wire from pin 0 (Serial receive) to pin 11 (mySerial transmit)? Note how they are crossed.
AltSoftSerial is really the best choice, but it only works on pin 8 (RX) and pin 9 (TX), which would require connecting 8 to 1 and 9 to 0. SoftwareSerial is very inefficient, because it disables interrupts for long periods of time. This can interfere with other parts of your sketch or other libraries.
My NeoSWSerial library is another alternative. It's almost as efficient as AltSoftSerial, but it works on any two pins. It can transmit and receive at the same time (unlike SoftwareSerial), but it only works at bauds 9600, 19200 and 38400.
EDIT:
I think what you've tried is probably working ok. All the software serial libraries use interrupts for processing individual bits instead of one interrupt per character. When there are other interrupts in the system (millis() TIMER0 or Serial), the bit "calculations" can be affected. This manifests as receiving the wrong byte. Your loopback test makes it especially susceptible because the sending and receiving are synchronized (the initial receive interrupt occurs while the transmit interrupt is starting the next char).
If you just hook 0 to 1, I think it will work, because the UART is able to send and receive at the same time, and it deals with complete characters, not bits. The character interrupts do not disturb the sending or receiving of the bits.
In developing the NeoSWSerial library, I have seen this manifest the same way. I had to use two Arduinos to fully test asynchronously (i.e., not synchronized). In your case, using AltSoftSerial for the SmartMeter should work fine, and you can choose different baud rates. If you are echoing the SmartMeter characters to Serial, be sure you have a higher baud rate on Serial.
This is most likely not related to the issues now 5 years ago, but in my case I was using the Arduino IDE 2.0.0-rc5 which was not writing to the soft serial for unknown reasons. I downgraded to Arduino IDE 1.8.19 and the same serial sketch worked.
I am trying to do a project based on arduino and Android in which I want to use ultrasonic sensors and Bluetooth module hc-05 . I want to detect any obstacle using ultrasonic and send it's distance to Android app using Bluetooth. I am completely new to arduino and have never used it before . How could I connect both the Bluetooth and ultrasonic sensor to arduino uno board without using breadboard? Is it possible to connect both of them without using breadboard and just the jumper wires?
You can connect the Bluetooth Module and Ultrasonic Sensor with jumper wires directly to the Arduino.
Depending upon the Ultrasonic Sensor you are interfacing, there must be a library or a sample code. You can tweak the code to get the distance in your desired format or variable.
As far as the Bluetooth is concerned, you can operate it at 3.3v or 5v depending upon the module you use. Most of the Bluetooth module support both 3.3v and 5v - as they have voltage regulators on their break out. I have used these and they work on 3.3v as well as 5v
For instance, check the Bluetooth HC - 05 Module in the below link :
http://www.amazon.in/Verve-VTA009-Bluetooth-Module-HC-05/dp/B00S15XTG8?tag=googinhydr18418-21&tag=googinkenshoo-21&ascsubtag=7a58e842-4c10-40bf-a48f-339edef372a7
For implementing the Bluetooth communication, prefer using the Software Serial. If you connect the Bluetooth HC 05's Rx and Tx to the Arduino's Hardware UART Pins, there can be unpredictable results. I have experienced that using HC05 with Software Serial is reliable. Additionally, you can use the Serial Monitor to debug your code at the same time. I mean, you can send the same data on Software Serial and the Serial port and check if things are as desired.
You can implement, the HC-05 Software Serial at 9600 baudrate. 9600 is the default baudrate on most HC 05 Modules.
For developing the Arduino code and testing it, you can use a terminal client like PuTTY on you computer. You need to establish a bluetooth connection between your computer and HC 05.
HC-05 runs at 3.3V, make sure you do level conversion from 5V to 3.3V using a zener diode. Or buy a level converter if you are new to electronics. If you don't, there is a good chance you will blow up the HC-05. If you could add a photo we can see if its already done on the Bluetooth module, then you need not worry about level conversion
HC-05 is basically a wireless serial port over bluetooh. On arduino create a software serial post using the library SoftwareSerial and send the sensor data to that serial port
There are libraries available for popular HC-SR04 ultrasonic sensor, if that is the sensor you are using.
For testing on android many app are availables like Bluetooh Terminal, you can receive the data sent from arduino.
Yes the whole project can be done without breadboard using connecting wires.
I have an Arduino 2560 and would like to send serial data to my PC. However, I am currently not using the Arduino Bootloader because I wanted to use a program that I wrote for an Atmega644 before (as far as I understood, one has to use the Arduino language when using the Bootloader?).
Does anyone know if what I am trying to do is possible with reasonable effort?
Connection to PC via 2560's serial0 does not depend on bootloader (if you plan connection when main program is running). You need 16u2 running to bridge 5V serial UART to USB or you can of course use any other option (e.g. MAX232 or so) to convert 5V UART to USB or RS232. But in case of RS232 double check baud rate error because of 16MHz crystal for particular baudrate.
2560 bootloader just implements firmware flash.
My question is pretty straightforward. I've got a big old machine that has an RS-485 connection on the back and I've got a converter from RS-485 to 9 pin serial.
The device I'm connecting to sends out an ACK signal to see if anything is connected. How do I wire up my Arduino (Uno) to the 9 pin serial connector so that I can read the ACK (and in future write back) and display the ACK signal in the Serial Monitor?
I would first check the voltage of the data lines coming from the RS-485 converter. The arduino ports are expecting 0 to 5 volts. Also, look-up the standard for RS-485 to determine what should be on the lines from the RS-485.
Notice, the arduino does NOT directly implement an RS-232 port. Rather, it has a USB port for connecting to a PC. I know that the RS-232 connection does NOT use TTL or 0 to 5V signals, and would question what signal levels are produced by an RS-485.
If the RS-485 does NOT generate 0 to 5 volts, then you will need to get an arduino RS-485 shield.
Finally, in fact, this is what you need to do. I just searched on "RS-485 Arduino" and found multiple hits.
Now, this is the good news, because once you have installed a RS-485 shield then you connect the shield to pins 1&2 on the Arduino and you have a serial connection!!
In most cases you need to wire only RX, TX and Ground signals (RX of Arduino to TX of RS-232 and vice versa). But it really depends on your RS-485 converter, if you need any additional lines. If this converter is half-duplex, may be you will also need to control it with DTR signal. You can use any digital IO on UNO then, and control it in software. Also you need to know the speed of serial port of this old machine, and configure UNO serial port accordingly.