Arduino Serial Output Garbled

Lab: Serial Output from an Arduino to Processing. last edited 30 August 2015 by Tom Igoe. Introduction.

Garbled data output from sensor through XBEE. However my resulting output on the UNO is How to send serial data from arduino to xbee and from xbee to вЂ.

Arduino - garbled serial output. I ve hooked up a ADH8066 Sparkfun GSM Module to my Arduino Uno, and am trying to get some correct serial going between the Arduino.

Ascii text is garbled when Arduino message is displayed in ScripCraft 3. simply want to pipe serial output from the arduino through conversation on GitHub.

Arduino is an open-source electronics prototyping platform the rest of the characters are garbled. This does not happen when using serial speeds lower than.

Used for communication between the Arduino board and a computer or other devices. All Arduino boards have at least one serial port also known as a UART or USART : Serial.

Serial.read has garbled data after a Serial.write. I had to flush the Arduino serial RX before sending any data pauses execution until the output buffer is.

Topic: Serial Output Garbled  Read 3070 times

previous topic - next topic

Matt R

Hello,

I m having trouble with one of my projects and I m not sure if it s a problem with serial or with power on my Arduino Duemilanova.  My basic set up is that I have an ethernet shield on the Arduino and the Rx and Tx pins 0,1 going out to a MAX2322 chip and the MAX2322 connected to a printer.  The Arduino checks a webserver for text and prints it on the printer using Serial.print.  I have it working great as long as my Arduino is getting its power over USB from my computer.  When I unplug the USB and plug in a 9V wall adapter to have it run while disconnected from the PC, the serial printer output is garbled.  I thought it was a power issue, so I tried powering the board with just a USB power source, and I get garbled output, or sometimes nothing.

I know that you may need more details to help out, but I wanted to check to see what the first hunches were.  Am I looking to fix a power issue or a Serial issue.

Thanks,

Matt

Are you connecting the power to Vin.

Have you connected the grounds correctly.

Is it a 9V DC output AC adaptor.

Can it supply enough current.

Yes, it s a 9V AC to DC Adapter that has worked for other projects, but this is the first time I m using it with the Ethernet Shield and the MAX2322.  It might be a current issue, I ll have to play around with it to see what i come up with.

Thanks.

From the symptoms,  the most likely cause is a bad ground connection.  What pins on the printer do you have connected to the Arduino.

Sorry, I m new at the electronics thing, so pardon me if I m not using the right terminology: I have the - rails on my breadboard hooked up to the ground on the Arduino with the printer s ground and the MAX3232 s ground connected to that, sorry for the bad pic, but here s what the breadboard looks like:

pluggy

Yes, it s a 9V AC to DC Adapter that has worked for other projects, but this is the first time I m using it with the Ethernet Shield

The official ethernet shield is a greedy b gger as far as current goes.  It uses around 7-8 times as much power as a naked arduino.  If the supply is a bit short of smoothing you could be getting very ragged DC out of it when its feeding the ethernet shield as well as the arduino.  If it has a  small output,it could be it just isn t man enough for the job.

Thank you everyone for your help.  Here s a very basic electricity question: should I then buy a DC adapter that has a higher output voltage or higher output amperes. I know you can supply too much volts to an Arduino.  Is it possible to have to have an adapter with too high of an ampere rating.

Based on what I m learning, I think I should get a DC adapter that outputs 12V and then a higher ampere output. I see mouser.com has 12VDC adapters that output anywhere from 100 mA to 2.0 A.  Should I just order the 12V 2.0A adapter.

THANK YOU.

Whatever you connect to the power supply will use as much current as it needs upto the limit of the power supply so a higher rated supply will do no harm.  A little warning regarding feeding an arduino with an ethernet shield with 12 volts, the arduino s regulator will get hot. 9 Volt is a safer bet if you re using ethernet.

I found a 5V 4.0A power supply and tested the voltage with my multimeter, and I was getting 5.27V.  Even with this power supply, I m having the same problems: garbled text.

Could this then be a ground issue. Is there a difference between the ground from the computer powered USB hub, to be accurate and a wall wart.

I decided to test the problem a few other ways.  I took a different Arduino Duemilanove board without the ethernet shield and wrote a simple Hello, World. sketch.  Under USB power, Hello, World prints fine, but under power from either of my AC adapters 9V 650mA and 5.0V 4.0A, I get no response from the printer most of the time and sometimes garbled text.  When I switch back to USB, it might spit out a little bit of garbled text, but then it goes right back to printing Hello World the way it should.

If this is a ground problem, how would i fix it.

Thanks again,

Ok, so Ran Talbott was right, it is a ground issue.  I tried powering the Arduino with my wall wart and connecting the USB s ground to the breadboard s ground rail.

Whenever the USB ground is tied into the circuit, it all works perfectly.  When I break that USB ground connection,  get nothing printed and sometimes garbled text.

If I get an AC-DC adapter that has three prongs that plug into the AC, will this solve my problem. Or is there a way I can fix this this while using the wall warts that I have only two prongs into the AC.  I guess I don t totally understand how the ground is being used.  My laptop which provides the USB ground only has two prongs going into the wall, so there must be a way, right.

Thank you so much to everyone who helped me out with this.  I tried connecting the ground to different pins on the back of the printer and finally found one that worked 100 of the time, no matter what the power source.

For some reason, the serial printer DB9/DB25 pin diagrams I found online don t match the printer that I have and the fact that it worked while powered under USB lead me to believe that I was using the right pins all along.

Now I m back to using the 9V 650mA power adapter that I ordered for the project and it has been working like a champ.

Thank you again for you help,

Matt.

I have a fio v3 a 9DOF sensor hooked up to an XBEE. On another UNO board, I have a GSM shield and another XBEE board.

The fiov3 is supposed to sample data from the sensor, send it through the xbee. The receiving XBEE will then receive and pass the data to the UNO. The UNo then activates the GSM shield on condition.

However my resulting output on the UNO is as shown :

The data received is corrupted.

CODE ON UNO.

/

XBee_Serial_Passthrough.ino

Set up a software serial port to pass data between an XBee Shield

and the serial monitor.

Hardware Hookup:

The XBee Shield makes all of the connections you ll need

between Arduino and XBee. If you have the shield make

sure the SWITCH IS IN THE DLINE POSITION. That will connect

the XBee s DOUT and DIN pins to Arduino pins 2 and 3.

/

// We ll use SoftwareSerial to communicate with the XBee:

include

// XBee s DOUT TX is connected to pin 2 Arduino s Software RX

// XBee s DIN RX is connected to pin 3 Arduino s Software TX

SoftwareSerial XBee 2, 3 ; // RX, TX

void setup

// Set up both ports at 9600 baud. This value is most important

// for the XBee. Make sure the baud rate matches the config

// setting of your XBee.

XBee.begin 9600 ;

Serial.begin 9600 ;

void loop

if Serial.available

// If data comes in from serial monitor, send it out to XBee

XBee.write Serial.read ;

if XBee.available

// If data comes in from XBee, send it out to serial monitor

Serial.write XBee.read ;

CODE ON FIOV3.

include // Included for SFE_LSM9DS0 library

define LSM9DS0_XM 0x1D // Would be 0x1E if SDO_XM is LOW

define LSM9DS0_G 0x6B // Would be 0x6A if SDO_G is LOW

// Create an instance of the LSM9DS0 library called dof the

// parameters for this constructor are:

// SPI or I2C Mode declaration, gyro I2C address, xm I2C address

LSM9DS0 dof MODE_I2C, LSM9DS0_G, LSM9DS0_XM ;

const byte INT1XM 4; // INT1XM tells us when accel data is ready

//const byte INT2XM 8; // INT2XM tells us when mag data is ready

//const byte DRDYG 7; // DRDYG tells us when gyro data is ready

const int buttonPin 15; // the number of the pushbutton pin

int buttonState 0;

pinMode INT1XM, INPUT ;

//pinMode INT2XM, INPUT ;

// pinMode DRDYG, INPUT ;

pinMode buttonPin, INPUT ;

dof.setAccelODR dof.A_ODR_1600 ;

dof.setAccelScale dof.A_SCALE_16G ;

Serial.begin 115200 ; // Start serial at 115200 bps

Serial1.begin 9600 ;

// Use the begin function to initialize the LSM9DS0 library.

// You can either call it with no parameters the easy way :

uint16_t status dof.begin ;

// Or call it with declarations for sensor scales and data rates:

//uint16_t status dof.begin dof.G_SCALE_2000DPS, dof.A_SCALE_6G, dof.M_SCALE_2GS ;

// begin returns a 16-bit value which includes both the gyro and

// accelerometers WHO_AM_I response. You can check this to make sure

// communication was successful.

// Serial.println status, HEX ;

//Serial1.println Hello. ;

buttonState digitalRead buttonPin ;

if buttonState 1

// Serial1.println Hello. ;

printAccel ;

//if Serial1.available

// Serial.write Serial1.read ;

//

void printAccel

// Only read from the accelerometer if the accel interrupts,

// which means that new data is ready.

if digitalRead INT1XM

// Use the readAccel function to get new data from the accel.

// After calling this function, new values will be stored in

// the ax, ay, and az variables.

dof.readAccel ;

Serial.print A: ;

// Using the calcAccel helper function, we can get the

// accelerometer readings in g s.

Serial.print dof.calcAccel dof.ax ;

Serial.print, ;

Serial.print dof.calcAccel dof.ay ;

Serial.println dof.calcAccel dof.az ;

Serial1.print A: ;

Serial1.print dof.calcAccel dof.ax ;

Serial1.print, ;

Serial1.print dof.calcAccel dof.ay ;

Serial1.println dof.calcAccel dof.az ;

Any idea how to mitigate this would be greatly appreciated.

Garbled serial output from breadboard ATmega328 via I also see similar garbled output through Arduino s serial monitor and minicom getting garbled output.

Serial Output Garbled

Debugging a 16x2 LCD Display on an Arduino. sometimes the LCD becomes garbled. I ve since experimented with wiring the RW pin to an Arduino output.