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more MotorMaster problems

I am trying to control a robot using the versalino uno, MotorMaster, BT2S Master and slave, and the versalino rove application. After driving for several seconds most of the time the motors I am driving lock up and get stuck in the most recent direction. I am unable to do anything from the computer I am using at this point. I have tried even unplugging the BT2SM from the computer, but the BT2S slave’s pairing light continues to stay on, and the robot continues to go out of control. Each of the 2 motors draw 6.6mA of current and are hooked into a gearbox. The MotorMaster power selection is set to ext and is hooked into 5.75v of power. The versalino uno is hooked into two cell phone batteries in series that together equal 8.4v of power. I have tried replacing the power regulator on the versalino uno, replacing the versalino uno, replacing the MotorMaster, replacing the motors, using a 9v instead of the cell phone batteries, using a different computer and so far nothing has worked. Also sometimes when the robot goes out of control this message pops up here is what it says.

Unhandled exception has occurred in your application. If you click
Continue, the application will ignore this error and attempt to continue. if
you click Quit, the application will close immediately.

A device attached to the system is not functioning.

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.IO.IOException: A device attached to the system is not functioning.

at System.IO.Ports.InternalResources.WinIOError(Int32 errorCode, String str)
at System.IO.Ports.SerialStream.EndWrite(IAsyncResult asyncResult)
at System.IO.Ports.SerialStream.Write(Byte[] array, Int32 offset, Int32 count, Int32 timeout)
at System.IO.Ports.SerialPort.Write(String text)
at Versalino_rove_controlpanel.mainwindow.SerialPort_SendData(String myMessage)
at Versalino_rove_controlpanel.mainwindow.respondPressedKeys()
at Versalino_rove_controlpanel.mainwindow.my_KeyDown(Object sender, KeyEventArgs e)
at System.Windows.Forms.Control.ProcessKeyEventArgs(Message& m)
at System.Windows.Forms.Form.ProcessKeyPreview(Message& m)
at System.Windows.Forms.Control.ProcessKeyMessage(Message& m)
at System.Windows.Forms.Control.WmKeyChar(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.TabControl.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

************** Loaded Assemblies **************
Assembly Version:
Win32 Version: 4.0.30319.1008 (RTMGDR.030319-1000)
CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/mscorlib.dll
Assembly Version:
Win32 Version: 4.0.30319.1001 built by: RTMGDR
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
Assembly Version:
Win32 Version:
CodeBase: file:///C:/Users/Dad/AppData/Local/Apps/2.0/37BB5ZGO.GC4/RNCW4DVN.1MA/vers..tion_83eb5e2372366bd9_0001.0000_258254bd5b9625a3/Versalino_rove_controlpanel.exe
Assembly Version:
Win32 Version: 4.0.30319.1002 built by: RTMGDR
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
Assembly Version:
Win32 Version: 4.0.30319.1001 built by: RTMGDR
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
Assembly Version:
Win32 Version: 11.0.50727.1
CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.VisualBasic.PowerPacks.Vs/
Assembly Version:
Win32 Version: 4.0.30319.233 built by: RTMGDR
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the section.
The application must also be compiled with debugging

For example:

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

Any help on this is much appreciated thanks.

5 Answers




So there are a couple of possibilities, but the first one to check is that your Batteries are providing enough juice for all of the devices. I usually test this by running the rover on external power (from an AC adapter) and check to see if you get the same symptoms. If not than something is drawing too much current from the Batteries (you can measure the currents with a Multimeter).

If you still have the problems then let me know if you have made any changes to the Rover Sketch, and I will work with you to do further debug on your system.


Ok I have 2 AC to DC transformers one is 9v 300mA for the logic, and the other is +5v  2A for the motors. Is 2A too much to put into the motormaster?


Ok I used the transformers mentioned above and got the same results.


It may be that your motors are drawing too much current, but it is probably a different problem. When we figure out the solution I will post it here. Don’t forget to remind me about the issue during your support call.


OK some new information, when I use my BT2S master and slave instead of my FTDI to control the robot I do not get the “I live.” println. Also, when I send a command over the serial monitor I get this message over and over again:

at Method)
Error inside Serial.serialEvent() Bad file descriptor in nativeavailable
at Method)

Usually it repeats so fast the serial monitor totally freezes up and I have to restart it.

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