USB motors and sensors for robotics

[dhicks]

Hello All,

I've searched via the forum search and via Google but have been unable to find much discussion so far about robotics in a school environment, so I'm sorry if any of this has been asked before.

What's the best way to go about controlling motors from the Raspberry Pi? Does anyone make USB plug-in motors that I can power via a USB hub and control with simple start() and stop() functions? Or do I have to use a separate (hopefully USB-controlled) relay device of some sort?

The same goes for sensors: does anyone make handy plug-in-and-go USB sensors for light, temperature, etc?

[liz]

We'll be exposing GPIO, I2C, I2S and SPI headers you can use for that sort of application - I hope we'll be making some add-on boards to make things even easier for you, but that's for next year! If you can find a USB device that's Linux-compatible, of course, that'll work too.

[Lakes]

http://www.robot-electronics.c.....08tech.htm

Uses Usb as virtual com port
Linux driver
http://www.ftdichip.com/FTDrivers.htm

or send USB/serial commands to a Picaxe board, you can buy a usb lead from there which has the same function as the ftdichip virtual com port.

[ked]

There is the Lego WeDo which I have used via Scratch and Python:

http://www.active-robots.com/l.....n-set.html

Also the GoGo board used on the XO:

http://wiki.sugarlabs.org/go/A.....ivity/Gogo

[dhicks]

Quote from liz on September 19, 2011, 23:07
We'll be exposing GPIO, I2C, I2S and SPI headers you can use for that sort of application

Thanks - after reading the replies here and a bit more searching on Google I have a better idea of the kind of thing that's available. Interestingly, I found the Phidget SBC2 single-board computer - similar to the Raspberry Pi (self-contained proper computer, runs Linux, networkable) and with inputs and outputs for sensors and motor control, but costs 10 times the amount. Does make you realise what Raspberry Pi is aiming to do - £250 for the basic controller, before any motors and so on, makes classroom robots rather expensive, but at £25 they become rather more affordable.

[dhicks]

Quote from Lakes on September 20, 2011, 09:53
http://www.robot-electronics.c.....08tech.htm

Many thanks - I see there's a two-port board, too, which looks quite affordable.

[dhicks]

Quote from ked on September 20, 2011, 11:10
There is the Lego WeDo which I have used via Scratch and Python:

That sounds like just the sort of thing I had in mind - plug in USB device, access it via Python API. However, reading up about it there doesn't seem to be any freely-available drivers and I don't see how I'd get the WeDo USB device to work on, say, Debian for ARM chips.

[ked]

Quote from dhicks on September 21, 2011, 10:07
That sounds like just the sort of thing I had in mind - plug in USB device, access it via Python API. However, reading up about it there doesn't seem to be any freely-available drivers and I don't see how I'd get the WeDo USB device to work on, say, Debian for ARM chips.

WeDo plug-in for Scratch (which I wrote):

http://www.assembla.com/code/s.....ugins/wedo

Python version by Ian Daniher:

https://github.com/itdaniher/WeDoMore

IIRC the Python version is based on the Scratch plug-in so both should be MIT licensed (but please check). You will need the udev rule file which can be found here:

http://www.assembla.com/code/s.....ratch.udev

BTW, there are many other options (including the now ubiquitous Arduino family) which might offer more flexibility depending on your requirements.

[dhicks]

WeDo plug-in for Scratch (which I wrote):

Thanks, I'll take a look.

BTW, there are many other options (including the now ubiquitous Arduino family) which might offer more flexibility depending on your requirements.

Indeed - the Phidgets single board computer looks very interesting, with assorted I/O options built right in to the board, but it's 10 times the cost of the Raspberry Pi. Actually, after investigating a bit, it looks like motor control should be relativly easy via a USB relay controller board, the tricky part is going to be finding sensors.

[gbulmer]

Quote from dhicks on September 19, 2011, 22:45
Hello All,
... .
What's the best way to go about controlling motors from the Raspberry Pi? Does anyone make USB plug-in motors that I can power via a USB hub and control with simple start() and stop() functions? Or do I have to use a separate (hopefully USB-controlled) relay device of some sort?

The same goes for sensors: does anyone make handy plug-in-and-go USB sensors for light, temperature, etc?

If your need isn't urgent, you might consider the Open Universities SenseBoard which will be part of their TU100 programming course. I was part of the design team.

It can control two DC motors, or one stepper, and servo's. It has 6 LEDs under user control, a sound sensor (for clap-on clap-off ) and plugable analogue sensors. So it might be sensitive to light, temperature, humidity, air pressure, or just bumping into a wall.
The OU's extended version of Scratch (Sense) uses a pretty simple protocol to communicate with it over USB.

I'm working on something which I think is better, but that isn't finished. You might have a look at my blog to get some idea of where I am coming from.

[gururise]

The UBW and the UBW32 are cheap too.

[gonzokawasaki]

hi

this topic interests me. I teach in a college and am currently undertaking a masters aswell in physical computing. I am interested in the aims of the Raspberrypi foundation. I teach games design to college students and although the focus is mostly on asset creation i encourage my students to explore coding.

I am interested in long term developments in re-introducing computer literacy into teaching.

At the moment i am exploring arduino and google IO as a platform for simple robotics. I would be interested in any developments along these lines with Raspberry pi.