I need to make a device to align some equipment in 3 dimensions. To adjust in one dimension I will use a Leonardo to read some distance sensors (the easy part) but for the other dimensions the alignment has to be done by centering registration marks in a camera view. This needs to be compact and easy to use. This means I need the Arduino and two USB cameras to share a single box and a single USB connection to a PC.
My questions are...
Can anyone recommend a cheap usb board level camera? Requirements are B/W, low res (640 x 480 is fine).
How hard is it to implement a USB hub chip? Since I want a single USB port on my device I need some way of getting the cameras and the Leonardo to share the single port.
I would be very surprised if an Arduino has the processing power to do what you want. A Raspberry PI might be a better choice for image processing. Even then it may not be simple.
"I would be very surprised if an Arduino has the processing power to do what you want. A Raspberry PI might be a better choice for image processing. Even then it may not be simple."
You are correct about that, but, I was not clear about the USB cameras.
I do not want the images processed by the Leonardo. I just want the images sent back to a PC for the operator to be able to view the alignment and correct it manually. The cameras will allow them to do that. The Leonardo is just there to get the distance sensor readings (16-bit values) back to the computer as well.
The reason I want the USB hub chip in the device is so that the cameras and the Leonardo can all be connected to a single USB on the PC side. But they should all be connected to the PC via the hub, not each other.
Thank you.
AndyCO:
The reason I want the USB hub chip in the device is so that the cameras and the Leonardo can all be connected to a single USB on the PC side. But they should all be connected to the PC via the hub, not each other.
Sorry, I misunderstood.
Aren't the regular off-the-shelf USB hubs cheap and suitable? I've seen some very small ones in shops and you could easily take them out of their plastic case if necessary.
Aren't the regular off-the-shelf USB hubs cheap and suitable? I've seen some very small ones in shops and you could easily take them out of their plastic case if necessary.
...R
Yes that is a good alternative, but now I am leaning towards the TTL board cameras for cost and size.
I looked at AMPS-N suggestion of the Adafruit 397 and that has me thinking that for low resolution images I could skip the USB camera/USB hub combination and use the Leonardo to just pump out the JPEG images from two cameras. The fps would be low but that is not an issue.
Also, I am looking at the SRCM2-GM-383 GHI Electronics, a TTL camera like the Adafruit, so that may be an option as well. Anyone have experience with that? How does it compare to Adafruit?
Grumpy_Mike:
If you don't mind the frame rate being one frame every fifteen seconds or so then this is a solution.
You are correct of course.
I can accept that as the price for getting the first unit built and demonstrating it, and if I can up the baud and go one resolution lower it won't be too bad. In any case it is for calibration only so it will be used infrequently. Once the functionality is there then I may rework the design using the USB hub approach.
I plan to move forward with the TTL cameras and I will report back the results and what I learn.
Thanks to all for your advice.