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Pand II with serial camera


#1

Hello,

I found some posts about panda II and camera. It was stated that the camera has to be serial but there were doupts about the memory. I didn’t get a clear “picture” if it is possible or not. For me if the camera send data through serial TTL and the Panda acts as a proxy this should work.

I would take pictures with following camera (see the link) and send the data directly through wifly (see second link) to my website. If I would read and send the data in small chunks this scenario should work right?

My ultimate goal is to have remote controlled car which is controlled from my web site and the car would send pictures back to the site so that I would know where it moves. The car is ready to rock and roll with ultrasound sensor to prevent collisions, I’m just missing the remote control part with camera

http://www.linksprite.com/product/showproduct.php?id=15&lang=en
http://www.sparkfun.com/products/10822

  • Tero

#2

On the surface, the serial camera you point to should work fine on a Panda, although RS232 level is unnecessary and a TTL level device would actually be easier to attach to the device - no intermediary level shifter adding complexity.

I don’t like to rain on your parade but I think that the constraints of the serial camera and the Panda will not give you what you are trying to achieve, or at least not meet your refresh rate expectations.

Think about the constraints like this:

What resolution are you going to use? 160120? Figure out how large a captured image would be - assume 8-bits per pixel, RGB meaning you get 160120*3=57600bytes in a raw format, which will obviously compress in a JPEG, but it’s a good starting point.

What baud rate are you going to use on the serial port? Default is 38400 baud, it can go up to 115200 baud.

Now you can figure out approximately how long the image will take to transfer over the serial port. Check out something like http://web.forret.com/tools/bandwidth.asp?speed=38400&unit=baud to give you some idea. For our 160*120 image and 115200baud, it will take 4 Secs to transfer the image to the Panda.

Based on all that, you can get an idea how quickly (not !) you could take a capture.

The Panda has limited memory - you need to buffer the data you get from the camera and put it somewhere. Where is that going to be ? Direct into a web response? Temporarily onto an SD card? That is also going to affect your speed of refresh.

I don’t think this is the right technology to achieve something that gives “realtime” interactive feedback like your potential use shows. If you want a shot every 10 secs (or every minute) for timelapse photography or later playback to see what the dog in the back yard got up to, it’s probably an ideal solution.


#3

Thanks for the reply, so it is possible. Yep, I know the refresh rate will be quite low even with jpg (average compress rate 10:1). But I think the camera will also be the bottleneck with only few shots / s. I would transfer the pictures directly through web response or if that is problematic, I will set up some simple program with socket that accepts my data and stores it for the web site.

I just want to build something complex and same time something interesting. It would be quite nice to run a lap in the house with the car from mobile phone just to see everything is ok ;).


#4

be careful with webresponse and seeing if you can directly fill that from the camera; good chance you will need room for a second copy of the image and you’ll struggle with that. But good luck with it all.


#5

If things get too complicated, I have access to Fez Spider with camera. So that will at least do the trick :slight_smile:


#6

sheesh, in that case I know which I would try first :wink: