I recently tried a small videocamera like this one, and i must say that, despite the low quality, they do a decent job, except when heavily shaked.
Now, the main problem is that they have a limited range, and that they have a radio signal on their own, separated from the main robot control. This means that you cannot make a program that behave based on the images, and that the two radio signals can have different ranges.
I was thinking: is there some solution to stream video live for example with an XBee module ? They can send up to 250kbps. Is it enought ? Which hardware could make some video compression on the fly ?
The Surveyor robot in earlier versions had a serial camera similar to this one. It used a Zigbee to transmit video data, though it may have been piped through the onboard ARM processor (in that version) somehow. Video would be somewhat jerky at 6 fps or less.
WiFi cams might provide a little distance, more than the vidoecam above, but less than XBee Pros.
Or a signal booster (with appropriate license) may get further range on the video camera.
I’m looking really seriously at a wireless Linux-based Router. Rik put the idea in my head ages ago. I’ve been reading about them for a couple of weeks and have found several software builds.
They run on 5 or 12 volts, they have USB ports, some have RS-232 ports (some have the breakout puns on the motherboard but need the 9-pin connector soldered on) and some software builds claim they’ve used them to stream webcams by WiFi. If they can be programmed to control a PIC from the serial port (which is dead easy on principle) that’s the route I’m going.
A colleague of mine has used one as a wireless internet radio. I’ll post details as soon as I can get 5 minutes to chat to him.
Now, the main problem is that they have a limited range, and that they have a radio signal on their own, separated from the main robot control. This means that you cannot make a program that behave based on the images
Forget on board image processing you won’t have enough power. Best way is to send signal to your pc let it send commands back to your bot based on image translation. So xbee would be fine for the pc -bot link. You would also need a graphics card with tv input.
Just be aware that machine vision is a complex subject. The CMU3 cam takes a lot of the hard work out of this task however I couldn’t afford to spend that sort of money myself.
yeah, i’ve considered that way before i found this site and the “start here” robot. I have opened a Netgear some time ago, it had all you said except for the USB port. They’re quite powerfull too. I’ve also modified and re-flashed the firmware (mainly to vandalize the web interface, but it could be used to add programs too).
the problems are two: first, they require quite some power. I’ve read around that wireless stuff use a lot of current, and the cpu surely consumes much more than a picaxe or arduino. No way powering them with some AA battery
The second is the range, which is quite limited. With my wireless router i can hardly cover my whole house, and i’m not living in a castle at all!
I guess those robots on the movies, that transmit clear live video from kilometers away are just impossible to build
Well, I wouldn’t dream of putting such an installation on any robot powered by anything less than a motorcycle battery!
Yeah. I have a wireless router in my garage. If I put my laptop on the opposide side of the wall (less than 50cm away from the router) I get ZERO signal. I had to put an access point in my living room to supply the rest of the house. I think that some house bricks have metal in them!!
(Aside: A colleague of mine who visited the cold war museum in Washington told me that when the Russians were building the American embassy, they put coins and bits of cable and any old metal crap they could find into the cement in order to confuse the bug-finders!)
I think it would be quite easy to build a robot to transmit video from several Km, but the FCC (or whatever the local legislation) rules would require it to have a radio licence. A CB radio is only supposed to have something like 4W output power. Some guys attach 20W boosters and can block out an entire city.
I guess if you’rere working for a spy agency or something, you don’t really care about licensing laws!!
I believe that it is used as Zigbee to transmit video data, though it may have been piped through the onboard ARM processor (in that version) somehow. I’ve also read, that wireless stuff use a lot of current, and the cpu surely consumes much more than a picaxe or arduino. No way powering them with some AA battery.
