This weekend I brought a little toy home to mess around with. I wanted to try it out for a long time. It could be useful in some applications in the m2m world which is becoming more and more present in our lives, although many do not realize it.

This little device is a mini camera module with VGA resolution from Comedia which in turn is based on a CMOS sensor from Onmivision (the world’s largest manufacturer of these types of devices, so much so that nearly all of us have one of their sensors in our mobile phones). So far it’s nothing special. The peculiar thing about this mini camera is that as well as its low cost, you can directly control a uart through a serial port with a very basic protocol suitable for everyone.

The latter obviously enormously helps you to be able to control the camera and get a picture of what is happening in the world from any device with a serial port. In my case, I am particularly interested in the possible integration with MTX65i modems, especially with MTXTunnel software. I am assessing how much time it would take to integrate the possibility of “taking a snapshot” from the MTXTunnel or even from the  MTXTunnelGPS.

The camera I’ve been testing is particularly the model I had at hand, the C328R. The following is the block diagram of the camera:

camara-serie-diagrama

It’s a very small camera (only 2cm x 2.8cm), with VGA resolution, with low power consumption (60mA) and as I said before with the serial control peculiarity (UART). Note that this camera has serial ports but doesn’t have an RS232, this means that RX and TX output level is 0-3.3V so we can’t directly connect to a PC’s serial port or a MTX GPRS modem. Fortunately, there is also a small evaluation board called C328-EV232 that allows this and adapts RS232 levels. This is what I am testing.

Here is a picture of the evaluation board next to an MTX65i so that you can see how big it is:

camara-uart

And here is another with the C328 module mounted on its mini evaluation board:

camara-rs232

Together with the mini evaluation board you get a CD-Rom with the datasheet from the camera and from the evaluation board itself, a rapid use test program (which does not work with Win7 but works with WinXP, it doesn’t really matter) and most importantly, the complete manual of the camera’s protocol which tells you how to configure the camera (resolution, compression etc.) and how to get an image from the serial port. It’s fairly informative which means that it is easy to do the first tests. This is a picture of the software test:

camara-serie-ejemplo

Basically, in addition to trying out the test program that comes in the CD-Rom, I have done some tests sending serial frames to the camera from a VB6 program. I followed the protocol and example in the manual and it responds very well. From what I gather, it doesn’t take much to generate the necessary JAVA code to take a snapshot from an MTX terminal.

It’s obvious that you can’t send video streaming from a GPRS terminal as the bandwidth does not allow it. But yes, it could be interesting to occasionally send some snapshots (we’re talking about very few KB, according to the settings less than 10KB per image) as this doesn’t cause any problems for GPRS transmission. For example, if we designed an alarm system using an MTX65i GPRS terminal, it could be interesting as we could send an image as well as sending an alarm. Or it could be interesting for a fleet management system (based on the MTX65 + G) that as well as GPS positioning via GPRS, it allows you to physically visualize the load at any given moment (for example when opening a trailer’s doors).

To conclude, if you sacrifice very little time and money, this little camera allows you to send photographs to any device that has a single serial port free. Small details like this are what differentiate devices that we can design over others, in a world which is becoming more and more competitive and in which there is more and more of everything.


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2 Responses to “Camera with Serial Port”
  1. yeimy says:

    Saludo.

    Estoy tratando de trabajar con una cámara serial RS232. La verdad no tengo información de la misma, no se como revisar el protocolo que usa o que pruebas puedo hacer desde el hyperterminal.

    Agradezco su colaboración.

  2. blogElectronica says:

    Hola Yeimy,

    que recuerde tienes los manuales en la web del fabricante Comedia.
    http://www.comedia.com.hk/

    Salu2

  3.  
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