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Rex – palm-sized, single-board computer for DIY robots

kickstarter.com

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Re: Rex – palm-sized, single-board computer for DIY robots

#21

Post by crunchex »

stinos wrote: post #14

Couple of things I wonder: - SdCard + full-blown OS = SdCard dies after a while? Or more serious problems like the rPi simply yielding it empty? Could another type of storage be used to boot and run from? - more information on the OS? What's it based on? Open source so we can fiddle with it? - what processor is that exactly? Likely the manufacturer provides an OS + libs for it as well (like Ti does for their OMAP), p…

Howdy, project creator here.

The OS is based on the Yocto Project, so it's a distro we're putting together ourselves. It's still under heavy development, but the goal is to have something minimal that we can throw all our support under without having to rely as much on other distros that already have tons of other boards/projects to worry about.

We haven't committed to open-sourcing the hardware yet, but all the software will be FOSS. The stuff we have so far is on github, and feedback would be great.

Re: Rex – palm-sized, single-board computer for DIY robots

#22

Post by crunchex »

jerryr wrote: post #15
ianbicking wrote: post #13

I always wonder with these boards why wifi isn't just built-in. It seems like a delightfully simpler interface than any wire, and means the base system can integrate with anything else over the network. Sure you can always add wifi, but the point of these boards is that they bundle all the basic stuff, and often include things like development environments that can't make use of wifi if they don't know if it is avail…

It's probably omitted to keep the base cost down. WiFi modules that you can get for low-quantity applications are expensive[1]. Cheaper modules generally require higher-volume consumer electronics applications--not to mention volumes of NDAs simply to get module documentation. Adding WiFi (or wireless comms of any type) also makes you an intentional radiator[2], which potentially complicates your FCC testing, adding…

Built-in WiFi was definitely on our feature-list, but you hit the nail on the head there - cost and FCC compliance were big issues. We decided to keep it simple and add it in via off-board solutions.

Re: Rex – palm-sized, single-board computer for DIY robots

#23

Post by veemjeem »

protonfish wrote: post #20

As a hobbyist AI programmer with few hardware skills my dream is a for an out-of-the box robot with basic movement, sensors and maybe an arm that I can start programming for in a higher-level language. Rex looks like a huge step in that direction. If they could throw in a chassis for mounting standard motors and sensors, even my multi-thumbed self might be able to make it do something cool.

You might want to check out ROS from the willow garage people. It's probably the right tool that you're looking for.

Re: Rex – palm-sized, single-board computer for DIY robots

#24

Post by zhemao »

ianbicking wrote: post #17
jerryr wrote: post #15

Earlier quoted context omitted.

It's probably omitted to keep the base cost down. WiFi modules that you can get for low-quantity applications are expensive[1]. Cheaper modules generally require higher-volume consumer electronics applications--not to mention volumes of NDAs simply to get module documentation. Adding WiFi (or wireless comms of any type) also makes you an intentional radiator[2], which potentially complicates your FCC testing, adding…

Thanks for those details, it makes more sense. People usually talk about the cost, which I don't buy – it's worth $10/unit, and these aren't super-low-cost units anyway. And in this case consumers of the Rex aren't going to develop something that will be the basis of thousands of units where that $10/unit cost becomes a big deal. But I can definitely see how the regulatory overhead would be a big deal, and it seems l…

The additional marginal cost/unit is pretty low, but the non-recurring engineering cost is pretty high, even without having to deal with suppliers and the FCC. Once you've chosen a wi-fi module, where do you put it on the board? How do you make sure the radio signals don't interfere with the rest of the circuit and vice-versa? It's much easier to just get a USB wi-fi adapter and install the Linux drivers for it.

Re: Rex – palm-sized, single-board computer for DIY robots

#26

Post by alexcroox »

protonfish wrote: post #20

As a hobbyist AI programmer with few hardware skills my dream is a for an out-of-the box robot with basic movement, sensors and maybe an arm that I can start programming for in a higher-level language. Rex looks like a huge step in that direction. If they could throw in a chassis for mounting standard motors and sensors, even my multi-thumbed self might be able to make it do something cool.

You should take a look at the Micro Magician V2 http://goo.gl/YunKFR, about a third of the size and motor driver/accelerometer/IR receiver built in. Great for small robots or doing high level coding (their Micro M library makes coding for those features a breeze)

Re: Rex – palm-sized, single-board computer for DIY robots

#28

Post by georgeecollins »

As someone who makes a lot of robots, I will support this on principle. I really like that the board can accept a high current power source and has a cutoff switch.

I am always a little nervous about building a robot around a board when I am uncertain about how it will be supported. If you are really building robots that are going to be used out doors or in rugged environments you want to be able to replace every part. Controller boards aren't really the expensive part of robots.

For Decapitron, an autonomous combat robot (http://forums.parallax.com/showthread.php/140197-Decapitron!), I have had to replace the controller board twice. That may sound like a lot but shorts and power surges aren't that strange in combat. But now that board isn't made anymore. So it is a big problem if the board gets damaged in combat. That's the advantage of using something really standard, like Arduino or Raspberry Pi. I can get one of those next year.

Still, I will try this.

Re: Rex – palm-sized, single-board computer for DIY robots

#29

Post by al2o3cr »

jerryr wrote: post #11
C-- wrote: post #7

Just asking to those with more knowledge than me. How is this any different to a RaspberryPi or a Beagle Bone Black?

IO expansion and power handling is one differentiator from the Raspberry Pi. The Raspberry Pi has a limited GPIO breakout (useful for many applications, but not tailored for robotics). And, besides not being designed to drive peripherals, the RPi's power system has some issues[1] that even make hosting USB devices a pain. It does seem like they could target the Beagle Bone Black and focus on the software, but they pr…

I'm kinda curious about the "20A" part - the PCB traces required to not melt the board while passing that much current would be pretty beefy...
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