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

http://www.kickstarter.com/projects/alphalem/rex-the-brain-for-robots

by pnr • 13 years ago

66 29 13 years ago

kickstarter.com

jboesch• 13 years ago

Very cool!

JakobStorm• 13 years ago

Nice!

khamoud• 13 years ago

Awesome!

Octplane• 13 years ago

Am I the only one to see $90.00 pledged of $90,000 goal with only 5 backers ?

Kliment• 13 years ago

Yes, looks like this just started today, so it's reasonable.

C--• 13 years ago

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

bad_alloc• 13 years ago

The RaspberryPi is supposed to be a computer you can use like a regular one. Rex seems to have a dual role: It's designed to control a robot (lots of pins and extension boards) and to act as a general purpose computer. So it sits somewhere between an Arduino and a RasPi.

georgemcbay• 13 years ago

The BeagleBone Black also sits in that range in that it is both an ARM-based general purpose computer but also has 2 real-time programmable microcontrollers onboard. Which isn't to say that this Rex project has no value, if it is produced it would be a much easier out-of-the-box experience for someone to just plug in some garden variety I2C motors and get going than it would be on the Black, but this sort of combined computer/microcontroller design isn't unique to it.

jerryr3• 13 years ago

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 probably wanted more control over the power and peripheral connect strategy than the BBB provides.

The processor they chose includes an integrated DSP, which could be useful for sensor data processing--or even motor control. The original BeagleBoard offered an OMAP with a DSP, but TI is discontinuing the OMAP line[2] and the newer BBB uses a Sitara A8 processor without the DSP. I didn't see the Rex's processor choice listed on the kickstarter page, but I'd guess it's something like TI's DM3730[3].

In summary, they seem to want to design a board specifically for robotics rather than building upon an existing general-purpose platform. This will give them more control over the power and peripheral strategy that will allow them to achieve a higher level of integration. This could also simplify software by limiting the number of busses and "tacked on" peripherals.

The founders come from Carnegie Mellon University, which has a first class robotics program. Also check out the CMUcam[4] project--an open source, computer vision module. The Pixy (CMUcam5) was funded[5] in September and looks really cool.

Edit: Check out the Rex page on the Alphalem site[6] too. It says that the "Rex can supply up to 20A directly from a 6-12V Ni-MH battery to connected devices. That's more than enough to power a couple servo drivers, Arduinos, rangefinders, and full servo load on an 18-servo hexapod robot!"

[1] http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=23205

[2] http://www.eetimes.com/document.asp?doc_id=1262580

[3] http://www.ti.com/product/dm3730

[4] http://www.cmucam.org

[5] http://www.kickstarter.com/projects/254449872/pixy-cmucam5-a...

[6] http://alphalem.com/pages/rex

al2o3cr• 13 years ago

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...

fosap• 13 years ago

I wonder how much power it drains. The RaspPi uses "only" 3 Watt, but that is a way too much for many interesting applications. There are some hacks to reduce to the power usage (by replacing the voltage regulators for example) but i wonder how much this board will use.

Florin_Andrei• 13 years ago

Well, in most cases when 3 W is too much, the application is simple enough that you could do it with an Arduino - which draws far less power.

ianbicking2• 13 years ago

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 available. Power is a concern, but you can still turn it off.

jerryr3• 13 years ago

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 cost and delay. So, from an MVP perspective, it makes sense to leave WiFi off if it's not critical to the base application--at least for your first revision.

[1] TI's budgetary pricing for one such module--the CC3000--is about $10: http://www.ti.com/product/cc3000

[2] http://en.wikipedia.org/wiki/Title_47_CFR_Part_15#C_-_Intent...

ianbicking2• 13 years ago

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 like that regulation also makes other aspects of integration more bureaucratic. Like I bet a bunch of these chips could be used inappropriately (e.g., to emit stronger signals than are allowed) and they are using NDAs and such as an alternative to other security measures. In a sense USB wireless standards are the one interface/security layer that is well enough spec'd that it is easy to integrate.

crunchex2• 13 years ago

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.

lazyjones• 13 years ago

If you need WiFi, you could start with one of those low-cost DD-WRT/OpenWrt compatible routers ($15-20 or so: TP-Link TL-WR740N http://wiki.openwrt.org/toh/tp-link/tl-wr740n). They have little RAM, but plenty of I/O (serial, RJ45) and they're still almost "palm-size".

stinos• 13 years ago

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), probably the board can be booted with that as well?

- will the schematics be open-sourced?

- debugging capabilities of running programs?

btw quite some comments starting with "I wonder" here. Authors should provide more information probably..

simcop2387• 13 years ago

The OS looks like it's just a linux distro, should be fiddleable (though not sure how easy). The rest I have no idea on yet.

http://alphalem.com/pages/alphalem-os

crunchex2• 13 years ago

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.

protonfish• 13 years ago

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.

veemjeem• 13 years ago

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

alexcroox• 13 years ago

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)

fencepost• 13 years ago

Am I the only one to see this and think "They're going back to PCMCIA?" (see http://en.wikipedia.org/wiki/REX_6000 for a "palm-sized single-board computer" complete with 240x120 monochrome touchscreen).

smilekzs• 13 years ago

http://alphalem.com/pages/alphalem-os

I like the reference to [MCP](http://tron.wikia.com/wiki/MCP)!

georgeecollins• 13 years ago

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.

joshu• 13 years ago

Stuff like this is why I run BigBoardList.

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

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