I'm trying to connect my Raspberry Pi 3 to an Arduino Mega 2560 over UART using the Rx and Tx pins (not USB cable). I went through all the steps to configure the Raspberry Pi to use the GPIO pins (https://spellfoundry.com/2016/05/29/configuring-gpio-serial-port-raspbian-jessie-including-pi-3/). For now, I'm just trying out the simplest code I can think of to make sure the connection is working (which it is not).
Arduino code:
void setup() {
Serial.begin(9600);
Serial.println("Start");
}
void loop() {
Serial.write(".");
}
Raspberry Pi code:
import serial
ser = serial.Serial('/dev/serial0', 9600)
while 1:
x = ser.readline()
print x
It's not giving me any errors or anything, but when I run the python code on the Raspberry Pi I get nothing. I'm using a logic level converter between the Pi and Arduino. Using a multimeter, I found that there is a signal going from the Arduino to the Pi, which is around 2.5V. Is this enough for the Pi? Could this be the problem? If so, what is causing it? I used 2 different Arduinos and I'm getting the same result from both.
I just don't understand what I'm doing wrong here and would really appreciate it if someone could help.
Related
I am trying to get my SIM800C to talk with my Arduino. There is no communication happening, though.
#include <SoftwareSerial.h>
SoftwareSerial at(2, 3);
void setup() {
Serial.begin(9600);
at.begin(9600);
}
void loop() {
// try every 2 seconds
delay(2000);
Serial.println("sending AT ... ");
at.println("AT");
while (at.available() > 0) {
Serial.write(at.read());
}
}
I am not able to get an OK back. SIM800C is supposed to detect the baud rate by itself.
I am sure there has to be a simple stupid mistake. I just don't know what to do at this point. I obviously already checked for cable break. Out of desperation I already tried to switch RX and TX. I also tried different baud rates (whatever is within the usual limitations of SoftwareSerial) but it should automatically detect it once a couple of AT commands got in anyway.
Weird enough, the pin PWX on the SIM800C needs to be hooked up to a GND to work. It started blinking every second now and is responding to AT commands.
Also it turned out that this specific module does not ship with autobauding enabled, as stated by the SIM800C documentation. The correct baud rate is 115200.
There are some problems you need to consider:
Use below sample code which transfers data between PC and SIM. Sometimes SIM module would go into power down state and won't respond on any AT command but would print some results in the serial monitor.
As already mentioned in comments it seems that your wiring is wrong and as you declared Software Serial as SoftwareSerial at(2, 3); which means pin 2 is Rx on Arduino and should connect to Tx pin of SIM and pin 3 is Tx on Arduino and should connect to Rx pin of SIM. Please don't mess with the pins and connect the pins like below correctly.
Arduino SIM
Rx 2 ----> Tx
Tx 3 ----> Rx
I'm not sure if you can power on SIM800 with a 500mA USB connector, make sure that use an external 1/2 A power supply for VCC of SIM module.
Look at the blink speed of SIM module if it connected and powered on it would blinky with 3 seconds delay and if it blinks fast, it means that it is being restarted. Also if SIM powered on correctly it would print some info like SIM READY, CALL READY, etc.
Try other baud rates like 115200 and see if you get anything on power on.
I put some macro definition to make pin mappings more clear.
#include <SoftwareSerial.h>
//SIM800 TX is connected to Arduino D2
#define SIM800_TX_PIN 2
//SIM800 RX is connected to Arduino D3
#define SIM800_RX_PIN 3
//Create software serial object to communicate with SIM800
SoftwareSerial serialSIM800(SIM800_TX_PIN,SIM800_RX_PIN);
void setup() {
//Begin serial comunication with Arduino and Arduino IDE (Serial Monitor)
Serial.begin(9600);
while(!Serial);
//Being serial communication witj Arduino and SIM800
serialSIM800.begin(9600);
delay(1000);
Serial.println("Setup Complete!");
}
void loop() {
//Read SIM800 output (if available) and print it in Arduino IDE Serial Monitor
if(serialSIM800.available()){
Serial.write(serialSIM800.read());
}
//Read Arduino IDE Serial Monitor inputs (if available) and send them to SIM800
if(Serial.available()){
serialSIM800.write(Serial.read());
}
}
Yes this module will not work in this configuration. There is a pin of V_TTL With 5V pin.. This pin enables the TTL logic converter of your GSM.. You have to connect this pin to 5V in case of arduino and to 3V in case of ESP8266.See the pin configuration here
I am working on a project and ideally I would like to start and stop the loop of an Arduino with a Raspberru PI. The idea is to send a signal from the Raspberry PI GPIO pins to the Arduino pins and trigger and ISR as follows:
volatile bool start = false;
void start(){
start = true;
}
void stop(){
start = false;
}
void setup(){
pinMode(2, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(2), start, RISING)
pinMode(3, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(3), stop, RISING)
}
void loop() {
if (start) {
//Do my stuff here...
}
}
Any help on how could I accomplish this from a C++ app that takes an argument, (start or stop, 1 or 0)? Or maybe with Python?
I chose to set two different pins on purpose. I am aware that we could have set only one pin and make it work as a trigger with a function "start = !start" however this way I will have a pin than will always start (or continue) the arduino and another to stop (or make sure the arduino is stopped).
One of my main problems is that I do not know how to set the connections between the two boards (one cable for each pair of pins or should we also need a ground?).
What type of impulse would be more appropriate to send from the raspberry PI?
I am also aware that the Arduino works on 5V and the raspberry pi on 3.3V. Should we connect a resistance in series to avoid any over current?
Thank your for any advice or bibliography you may provide,
Alexis
With respect to your concern about the voltage issues: I would address this first because that has to be established before anything else will work.
Indeed, the voltage on the Raspberry Pi is 3.3 volts and typically Arduinos are 5.0 Volt logic. There are voltage level converters available that will convert 3.3. to 5.0 and back. You can get these from common sources such as Adafruit or Sparkfun. Specifically the name is
**4-channel I2C-safe Bi-directional Logic Level Converter - BSS138 $4.00 **
You can wire the communication between the two devices using this simple device. (Shown is the Sparkfun version).
Alternately and possibly simpler would be to purchase an Arduino that can be run at 3.3 Volts. These are available from China on eBay and have a switch that allows the arduino i/o to be either 5V or 3.3V.
It is possible to use resistors to manage the level conversion. You may want to consider this solution if you have the skills to design it.
I am new to Intel Galileo. I am trying simple things. How do I use serial TX(Digital pin 1) and serial RX(Digital pin 0) for communicating with other UART devices ? Which serial port is this UART ?
I tried to connect it by configuring it as uart 0/1/2 but did not work.
void setup() {
Serial1.begin(9600);
}
void loop() {
// put your main code here, to run repeatedly:
Serial1.println("Hello Galileo");
delay(300);
}
I have never used the Galileo but I was not aware that it had more than 1 serial port. So basing my thinking on the UNO as well as the MEGA, pin 0 and 1 should not be Serial1 but just Serial, meaning that if you connect the TX pin to the RX pin of another device and then, as you posted above, run your code with Serial.begin(9600); and Serial.println.... instead of Serial1.... it should work as far as I know... Also, I sometimes use Serial.Write but I am unsure of what the difference is. I normally would not answer a question I don't know the exact solution to but as there are no answers yet I thought I would give it a try.
I'm using a Gen2 and the latest build of Windows IoT (9600.16384.x86fre.winblue_rtm_iotbuild.150309-0310_galileo_v2). In that build, Serial is the correct object for COM1 on pins D0 and D1 and I've used it successfully.
Serial1 is supposed to be COM2 on D2 and D3, but I get an error when I try to open it. I'm still working on that.
I am using arduino uno to make a sound detector.
I uploaded a program, found error in the code that it returns unintended numbers unreasonably big. I also think I used wrong code for the module, but it was connected in the way that can work properly with the proper code.
The code I uploaded was:
const int ledPin =13;
const int middleValue = 512;
const int numberOfSamples =128;
int sample;
long signal;
long averageReading;
long runningAverage = 0;
const int averagedOver = 16;
const int threshold=400;
void setup(){
pinMode(ledPin, OUTPUT)
Serial.begin(9600)
}
void loop(){
long sumOfSquares = 0;
for (int i=0; i<numberOfSamples; i++){
sample = analogRead(0);
signal = (sample - middleValue);
signal *= signal;
sumOfSquares += signal;
}
averageReading = sumOfSquares/numberOfSamples;
runningAverage=(((averagedOver -1 )*runningAverage)+averageReading)/averagedOver;
if(runningAverage>threshold){
digitalWrite(ledPin, HIGH);
}else{
digitalWrite(ledPin, LOW);
}
Serial.println(runningAverage);
}
When the arduino suddenly stopped sending serial numbers, I pressed reset button and uploaded the default code:
void setup() {
}
void loop() {
}
but now it shows that it cannot connect to COM3 (arduino) and cant find the device, When I can see arduino uno successfully connected to PC using device manager (windows 8.1). The led light of arduino also turns on when I connect it to power source or usb.
it shows "port not found" when I click to see the serial output
Did I just fry Arduino?
How should I fix this?
Also, i checked the led pin 13 blinking three times when i plug in the usb. I just cant upload anything
What worked for me:
Tools>Port>(your COM)
Just selecting that solved the error.
You should do a few checks in order to jump to a conclusion, your Arduino may be just fine. As far as I know, Code cannot destroy a controller.
Check if any other software is using the same serial port. Two softwares cannot use the same serial port at the same time
Restart your PC and then try again
Remove the Microcontroller from the board, connect it to the PC and try to open the com port. If it opens then connect your Tx pin with the Rx pin, send some data and check if you are getting the data back. This way you will ensure your USB-TTL converter is fine
If this goes successful, then insert your microcontroller in some other board and check if it is getting programmed
I am sure after these checks you will find out the reason of the failure of your board/microcontroller.
Yes, check everything.... especially the USB cable or the USB port. It is crucial. My problem was just dirt on the computer USB port. Dirt, dust and grime. Crazy isn't it ? Just clean up the USB port and connector and the problem solve.
I also had a same problem and solved it.
try this one.
1. disconnect all cables from your arduino
2. connect external power
3. connect usb cable
4. then upload it.
I used my arduino with CNC shield(GRBL) and plugged external power to arduino.
after this. it was not possible to upload new firmware to arduino with usb cable only.
Once you success to upload with usb + external power then you can upload any firmware with usb cable only.
To solve the problem.
Method-1:
Go to Tools>Port>Select the Port
Method-2:
Unplug your board and plug it back in.
Method-3:
Restart your computer or laptop and reinstall Arduino software.
For more details you can visit "https://arduinopoint.com/fix-most-common-error-uploading-to-arduino/"
I have a USB 2 Serial adapter and the device is working fine. I see the device perfectly configured in my System.
I have connected the TX0 pin of Arduino to DB 2 pin (read pin) of the adapter. Below is my Arduino code:
int i = 0;
void setup()
{
Serial.begin(9600);
}
void loop()
{
for(i=0;i<6;i++)
{
Serial.write('H');
delay(100);
}
}
But when I try to read thru terminal software of data received at my COM port I see some junk character incoming. I am pretty sure that I am using same baud rate / flow setting both side. Why am I facing this issue - do I need to connect any other pins also as I just need to receive data at system side?
You should connect the ground pin with the ground pin
Arduino Communicate with Ur computer using pins 0 and 1( Tx0 and Rx0)
you shouldn't be connected to the Tx0 pin to another serial device because arduino use it to communicate with computer.
if you are using Uno. Check for Software Serial. and two grounds should be connected.