Anyone played with Gumstix?

[Somchaya]

Has anyone played with the Gumstix boards personally? I've been looking at them, and they look pretty neat, but I've heard that students at my school who use it for the embedded systems course are complaining a lot about it.

In particular, there's a new (I think) system that allows USB host: http://docwiki.gumstix.org/Verdex. This sounds really cool to me, but I'd like to hear some opinions about it from people who have had first-hand experience with the device, or Gumstix in general

Hmm, I guess my main questions are:

1. Is it easy to develop software on it? They run linux, so it shouldn't be too difficult to code up stuff in C, and gcc it? Is that true, or will I encounter various miscellaneous problems getting things to work?

2. How does interfacing devices on the Gumstix work out? I'm especially interested in attaching a webcam of some sort to the Verdex board, since it has USB host capabilities.

3. Regarding the Robostix, how does working with it feel? I remember reading somewhere that getting when you plug a Robostix into a main board, writing a program that interfaces with both boards is kind of tricky.

Thanks!

[Admin]

I've heard that students at my school who use it for the embedded systems course are complaining a lot about it

just out of curiosity, what were their complaints? (just in case one day I decide to use gumstix)

[dunk]

ooo. interesting. i've been wondering when gumstix would get USB host working.
also on the specs under features it says "CCD camera signals".

as for developing on the gumstix, it should be straight forward enough.
it's a linux based board so just install GCC can you are good to go.

i'm afraid i can't answer your other questions though.

dunk.

[Somchaya]

just out of curiosity, what were their complaints? (just in case one day I decide to use gumstix)

This is third-hand information, since I heard it from a friend who has classmates using gumstix..

They said that developing on it was a pain (not much details on that unfortunately), and getting things to work on it was rather difficult. My impression was that connecting to the linux kernel, putting programs and compiling was a problem, and also interfacing with other devices that they connected it to, maybe sensors and such..

[JonHylands]

I have used the gumstix in a couple applications so far:

http://www.huv.com/roboMagellan

http://www.huv.com/blog/2007/04/brainbot.html

The verdex (which is the board I have for the humanoid) indeed has USB host - so far I have gotten a USB wifi dongle working with it, and a USB thumbdrive.

I do my gumstix development in Smalltalk, so I am fairly insulated from Linux or the kernel or other low level stuff. On the rover above, I use the serial ports to talk to a GPS and a PIC micro-controller. The PIC handles all the hardware interfacing (sensors and actuators).

On the verdex, I am planning on using USB to talk directly to the Bioloid bus, and wifi to provide a high-bandwidth pipeline back to the PC.

- Jon

[Somchaya]

Hmm.. to get USB host, I'll need to get a Verdex as well as an expansion board correct? eg the console-vx or breakout-vx boards?

Also, have you experimented with the Robostix board?

My intention is to have a board (or multiple ones) that will have USB host. I'm hoping to set up a wireless connection with it with a USB wifi adaptor, and possibly hook up a USB webcam to it too.  And for input/output, I guess some analog and digital ports would be needed, hence the stuff about the Robostix.

Will getting a Verdex be sufficient or will I have to get the Robostix to do the input/output parts?

Also, I'm wondering how powering the device is like. It seems like Gumstix sells wall adaptors, but I'll want to eventually run it off batteries, is that possible/easily done?

[JonHylands]

Well, technically you can get the USB host signals directly off the verdex board (it has a third connector, called the "flex" connector, which has the signals on it.

For my money, its a whole lot simpler to plunk down $20-30 and buy one of the 60-pin expansion boards (like the just-announced console-vx or breakout-vx).

Apparently you can drive a certain amount of I/O using the breakout board,  but it would have to be at 3.3 volts, and you'd have to do driver-level programming in Linux to do it. Much simpler to just use a robostix.

However, you have a problem - the robostix gives no access to the USB signals, so you're basically stuck with either:

- use the flex connector for USB & use a robostix for I/O
- use the breakout-vx board (subject to the above caveats)
- use the console-vx, and have it talk to your own microcontroller over one of the serial ports provided

Note that if you're planning on hooking up more than one USB device to the verdex, you will need a USB hub. If you can wait a few weeks, they should have the wifi-120 boards available, which will mean you only need to hook up the webcam via USB. Make sure you find a webcam that has Linux drivers available in source form...

- Jon

[Somchaya]

Hmm.. how do you do the I/O for your robots then?

I'm thinking of getting the verdex some time not too soon, so I'll probably wait for the wifi module.  I'm thinking of using it for a simple-ish robot (the omni-directional pole balancer) that doesn't use the USB host ports, but I just want the capability in there so that I can use the verdex for more interesting applications after that.

Right now my main concern is whether developing on the verdex and robostix will be as painful as I heard..

Oh, if I get the verdex and robostix, do I still need the ISP cable to program it or can I do that through the verdex?

Thanks a lot!

[JonHylands]

I use option #3 from my post. Although with the verdex, I'm using the USB host capability to talk to a FT232 USB chip, which, through a tri-state buffer and an inverter, can talk to the Bioloid bus directly. Since all my sensors and actuators are on the bus, all the data goes through that one interface. The only exception to that is the cameras, which have their own wireless link to the PC.

If you do AVR programming now, working with the Robostix really isn't a big issue. You can program the robostix using the gumstix, or using a normal programmer (of the ten-pin variety).

One of the nice things about the gumstix/robostix combo is you can replace the gumstix with your PC anytime, if you need to debug things on the robostix with a better environment.

- Jon

[Somchaya]

also on the specs under features it says "CCD camera signals".

Hmm, I'm not very clear on this part actually.. What do they mean when they said it accepts CCD camera signals?

[JonHylands]

The PXA270 has bulit-in firmware to connect to certain types of CCD cameras (along the lines of the type of camera they put in mobile phones).

I don't know specifically what camera - you'd probably have to ask on the gumstix mailing list to get an answer on that.

- Jon

[Somchaya]

Hmm.. right now, I'm thinking of using the Verdex for main processing, and stuff like wireless (when they come up with the wireless add-on). And for I/O, maybe the $69 Linux board that Admin linked to: http://www.societyofrobots.com/robotforum/index.php?topic=926.msg6272#msg6272.

That board seems to be able to do I/O, in addition to being able to talk via Ethernet, which is cool. I haven't really looked into the board very much yet though, but I'll probably do so after my finals in a few weeks.