Go Down

Topic: VB 2010 & Arduino Uno - Serial Communication (Read 3907 times) previous topic - next topic

Can not make VB 2010 to work with  Arduino Uno. I am a beginner. Please check my attached files and tell me where i am wrong.


I'm using Linux and it's a long time since I did anything with VB.

In this Thread I recently wrote a Python program and corresponding Arduino sketch to illustrate communicating with a PC. The principles will be the same whatever language you use.



You probably ought to call Serial.begin() in setup. Without that, nothing gets written to the serial port, or read from it.


I add Serial.begin(9600);
Nothing happen.

This doesn't sound like a serious attempt at debugging.

Have you tried sending/receiving data to/from the same Arduino sketch using the Serial Monitor? Does that work?


HI Robin2,
Your are right. I checked it again and realized that I put "Serial.begin(9600)" in "void loop()".
Once I moved it to "void setup()" section, everything work. ...... Beginner at the beginning.
Sorry guys. It works now. Thanks..

Hi Robin2,
After one run with VB 2010, Arduino stops responding. I have to unplugged/plugged USB in order to make it work.
I have to do the same procedure again. Do I miss anything ?.


Do you get the same problem when using the Arduino Serial Monitor, or only with VB?

It sounds like the Arduino is resetting, and a common cause of that is someone trying to power a motor from the Arduino board. Motors generally draw too much current and should have their own power supply.

Does the program seem to work properly if you disconnect the motor?

If the problem exists with both the Serial Monitor and VB then you should sort out the problem with the Serial monitor before you introduce the complication of VB.


Motor works OK all day long without VB. There is no one else using the same com port but me.
After loading VB, the motor responses one time and no more. I have to close both VB and Arduino sketches, then unplug USB
After that, I plug USB back, load VB and Arduino sketch. It works for one time and stops.
I think my VB program is the culprit.
Thanks for looking into it.


Is it possible your VB code is inappropriately closing (or not closing) the serial port?


Hi Robin2,
Found the problem. I did not reset my variable "count" in Sketch.
So after the first run, the variable is out of range. That is why the Sketch stops
Thanks for all your help.


Glad it's working and thanks for telling us what solved the problem.


Today, I have another problem with Arduino Uno to receive string text.
from VB 2010:

then upload the attached *.ino file. Then open Arduino serial monitor to track progress.

Please help.


I haven't seen anyone testing for the serial buffer being less than empty before.

Nevertheless look very carefully at how your IF statements are organized and ask yourself when the second one will be triggered.

"Very carefully" means go through the code step by step with a pencil and paper.



Apr 24, 2014, 12:26 am Last Edit: Apr 24, 2014, 12:29 am by HugoPT Reason: 1
Some help...
Code: [Select]

//You need space for the null terminator, since you want 3 characters you need an extra to the null terminator 3+1
#define STR 4
char buffer[STR];
void setup(){
void loop(){
 if (Serial.available() <0) {   //Ok if you dont have nothing print like crazy ...
 if (Serial.available() >=3) {//It will need 3 bytes to run, this way you insure it's safe to read the 3 bytes in a while loop
//Serial comunication are very slow, if you try to read the 3 bytes when you detect the first one you will not get the next because the second one hasn't arrived yet
   int i = 0;
   while (i <= 2) {
     buffer[i++] = Serial.read();//Use i and then increment it after
   buffer[3] = '\0';//In order to print it below like a string you need to terminate the char array with a 0
   Serial.print("OK I received");
   Serial.println(buffer);    //Here you should get the string correctly

Obvios this is presuming you are just sending 3 characters from the VB
Arduino Mega 2560
Arduino Nano
Arduino Duemilanove
MAC OS Montain Lion
Raspberry PI Model B

Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131