Need Help with MIT App Inventor Robot Arm and Mecanum Wheels Project

Hey everyone,

I hope you're all doing well. I recently attempted to replicate the Arduino project created by Dejan, which involves an Arduino robot arm and mecanum wheels platform with automatic operation. I followed all the steps outlined in the tutorial on the HowToMechatronics website, including using the MIT App Inventor application that was provided.

Unfortunately, I've encountered an issue where the buttons in the MIT App Inventor application don't seem to be working when I connect it to my robot. As a result, I'm unable to control the robot as intended. I've double-checked my connections and followed the instructions carefully, but I'm still facing this problem.

I'm not very familiar with the intricacies of the methods used in Dejan's project, and I'm not an expert in MIT App Inventor, so I'm a bit lost on how to resolve this issue. I believe there might be others in this community who have experience with this specific project and could provide some guidance.

If anyone has encountered a similar problem or has expertise in MIT App Inventor and Arduino projects, I would greatly appreciate any insights or solutions you can offer to help me get my robot up and running.

Thank you in advance for your assistance, and I look forward to any advice or suggestions you may have.

Robot_Arm_and_Mecanum_Wheels_Robot.aia (513.9 KB)
MWRA.ino (14.4 KB)

(Canned Reply: ABG- Export & Upload .aia)
Export your .aia file and upload it here.

Also include your .ino sketch.

Sorry, I edited and included both .ino and .aia.

I checked for data type consistency between what the app is sending and both look okay to me:

int dataIn;
int m = 0;

void loop() {
  // Check for incoming data
  if (Bluetooth.available() > 0) {
    dataIn =;  // Read the data

    if (dataIn == 0) {
      m = 0;
    if (dataIn == 1) {
      m = 1;
    if (dataIn == 2) {
      m = 2;

The transmitting blocks:

  • So your sketch data is int type (2 bytes?)
  • You are sending 1 byte integers
  • returns what?

I throw this thread up for the hardware guys.

I used 11.1V 25C 1800mAH li-po battery instead of 11.1V 35C 3500mAH which used by Dejan, the project creator. Does this mean that my robot doesn't have the correct power supply?