8 SERVO 08.2015
4D Systems uCam-II
In my last two columns, I have been discussing the pros
and cons of the uCam-II UART interface color camera from
4D Systems (see Figure 2). I got the camera communicating
at nearly 1 Mbps to my controller board, which was about 3
fps. This isn’t quick enough for most robot navigation, but
can be used if the robot is not very fast. If you have a UART
that can better match the uCam-II UART rates, then a bit
rate of over 4 Mbps ( 12 fps?) could be possible, which is
fast enough for navigation. This camera is $49. 4D Systems
has its Workshop 4 IDE (free) to help you to configure your
camera board very easily. Go to www.4dsystems.
com.au/product/uCAM_II/ for more details.
The CMUCam5 Pixi
The next vision board to consider is the venerable
CMUcam series. CMUcam’s 1-4 have been retired and
replaced by the newest in the line: the Pixy CMUcam5.
Smaller, better, faster (one assumes; Figure 3). CMUcams
have object tracking software built into them, and also nifty
Java based tools to use on your computer to help you
configure and test the camera.
This camera can output results at 50 fps, so tracking
speed is definitely adequate for robot navigation
experiments. Not only that, this vision board doesn’t just
output images, it tells you where things are and even has a
built-in pan/tilt function for servos. The CMUcam5 can be
purchased in many places; check out their website at
www.cmucam.org/. As you can also see, this is an open
source project with lots of users to help you on your way.
The cost of a CMUcam5 is from $70 to $85, depending on
Arducam Shield and
Because you can’t seem to talk about robots without
talking about Arduino, there is the Arducam series of
Arduino compatible cameras. There are two that I know of:
the Arducam Shield Rev. B or Rev. C ( www.arducam
.com/tag/arducam-shield-2/) which come with a
bewildering set of options. One nice feature of this board is
a built-in uSD card slot for image storage. The other nice
feature is the camera data SPI interface has a maximum
clock speed of 8 MHz. This means that a 320x240
RGB(565) screen of 76K bytes can stream at about 13 fps.
The Arducam Shield is an open source project, so full
schematics and code is available to users and hackers to
play with. It was not easy to find documentation for this
shield, but Google came to the rescue: www.arducam
.com/category/user-guide/. The documentation is not
extensive, so there will be some challenge to your project!
The Arducam Shield is simply an interface to a camera;
there is no processing done on the shield. That project is
left to the program running on the microcontroller board.
See Figure 4 for an image of the shield sans camera
module. The Arducam site points to the UCTronics site for
purchasing them ( www.uctronics.com/catalogsearch/
result/?q=arducam+shield), where the shield without a
camera costs $29.99. Camera modules appear to run from
$6 to $13 on that site. Or, you could go to Marlin P. Jones
and get their entry for $39.95, which comes with a two
megapixel camera installed ( www.mpja.com/Camera-