Servos don't work

[jpflorido]

Hi folks!!

I'm new in this CMUcam2 world :-). I bought the camera some months ago and it works OK. Recently, I decided to buy a couple of servos for motion purposes. The model are HS-422. I've tried to use them, but they don't work...

First of all, I tried to connect them via board power, with the servo internal power jumper in place... but they don't work... the power was around 12V and the intensity about 300mA.

Then, I decided to buy another power adaptor to run the servos off of external power. I leaved the jumper opened and the servos were connected to an external power... I tried from 6V to 12V... but, still, they didn't work. Well...with 12V, the servos moved, by themselves, to the initial positions when they were connected for the first time, but then I tried to move them to another positions and they didn't move....

What Am i doing wrong???

Can anybody help me, please??

Thanks in advance,
Javier.

[Mike Betts]

Javier,

What program and platform are you using to communicate with the CMU2cam?

It would help to see the code you are using to initialize and command the CMU2cam. Also, what type of target you are seeking.

Be advised that this forum is for the FIRST robotic contest. The majority of posters here high school students and their experience is specific to a PIC18F8722 or PIC18F8520 hosting the CMU2cam on serial port 2 and targeting a bright green cold cathode target.

Regards,

Mike

[jpflorido]

Thanks Mike,

I'm using Visual Studio 2005 on Windows XP. The code is written in C#, but I also have tried with the GUI that the camera brought in Java and the servos didn't work either...

Here is the code I used:

// Set the COM1 serial port
SerialPort port = new SerialPort("COM1", 115200, Parity.None, 8, StopBits.One);

// Infinite ReadTime Out (default)
port.ReadBufferSize = 100000; // Size of the buffer: 100000 bytes
port.Open();
port.DiscardInBuffer(); // To empty the buffer


/* PART 1*/
port.Write("\r"); // Send command \r
while (((char)port.ReadByte()).Equals(':') == false) ;
// ':' received

/* PART 2*/
port.Write("SV 0 130\r"); // Send command SV to servo 0 at position 130
while (((char)port.ReadByte()).Equals(':') == false) ;
// ':' received


And for these two commands I received ACK....but the servos don't move!!!

Any tip...would be great.

Thanks again,
Javier.

[Mike Betts]

Javier,

I see nothing wrong in what you have done. In particular, I know that the GUI developed by CMU works just fine. In the absence of anything offbeat (like plugging in the servo backward), I think you may have a bad unit.

Regards,

Mike

[jpflorido]

Thanks Mike,

I've checked that there is no plugging in servo backward....so, as Mike says, it may be a bad unit...

Anyway, if somebody else had the same problem or knows any guess, would be great.

Thanks again,
regards,
Javier