What's Required for Robotic Applications with Raspberry Pi?

[calculusFTW]

Hello everyone,

I finally got a Raspberry Pi and finally have enough time to start on a project with it. I've never used one before, but I am familiar with Linux, especially Ubuntu, from my work as a software developer. I've also built some simple robots, first with Arduino, and later with various AVR Microcontrollers.

I'd like to build some more sophisticated robots using my Pi and ROS (http://www.ros.org).

But I'm having some difficulty parsing through the myriad of peripherals, accessories, and tutorials about the Raspberry Pi. So I have two questions: A) what accessories will I need, as a minimum, to get started?

I already have a 4gb SD card, several USB cables, a few motor drivers, several sensors of various types, a couple of robot chassis, and tools. Soldering is not a problem. I have stand offs for mounting the Pi, and a handful of Arduino boards I can use for interfacing with/controlling actuators and sensors, so the Pi's processing power can be reserved for running ROS, decision making, and navigating. What else would I need?

Question B) is more specific: which Adafruit USB Wifi dongle should I get? I know the ones in the Raspberry Pi section of the store have been selected to work with Raspberry Pi and Beagle Bone, but I read that you need one with a certain driver in order to use the wifi dongle in Ad-Hoc mode, and I definitely want one that will do that. Assuming Adafruit has one, will it work as an access point also, in addition to Ad-Hoc mode?

Thanks in advance, gurus! I know you will steer me in the right direction.

[adafruit_support_mike]

The best suggestion I can give you is to head over to the MagPi magazine archives and read all the issues that talk about the 'scutter' robot that's been developed over time. At minimum, that will give you some idea of the hardware and issues involved.

http://www.themagpi.com

[calculusFTW]

Thanks, Mike. I'll check that out.

In regards to my other question, can you tell me if any (or all) of the usb wifi dongles in the Adafruit store will work in both Adhoc mode and as an access point? I read on RPi VerifiedPeripherals http://elinux.org/RPi_USB_Wi-Fi_Adapters that to connect in Adhoc mode, you need one with the nl80211 driver. Thanks.

[adafruit_support_mike]

They should all work, but some people have trouble with the smallest one.

The problem seems to be that the wifi dongle wants slightly more power than the RasPi's USB ports can deliver, creating one of those situations where the component tolerances on both devices become important. It doesn't happen all that often (we go through the little things by the crate), but you'll find plenty of help requests here in the forum.

We rarely hear anything about the other dongles though, and again, we sell lots of them. It seems reasonable to assume those work without any trouble.