Wednesday, 27 March 2013

Learning the Lingo

Owning a Raspberry Pi automatically earns you a place in a huge, vibrant, buzzing community that's forever growing and creating. The grand master Eben Upton, co-inventor and founder of the RPi and the Raspberry Pi foundation, has created something that can instil wonder and awe, as well as excitement and curiosity from the moment a Pi is placed into your hands. His wife, Liz, runs the Raspberry Pi website; quite possibly the only blog on the internet to be updated multiple times a day by the same writer! It's fantastic!

The forums are filled with endless streams of questions and answers on the most obvious of queries, to the tiniest troubleshooting problems. And EVERYONE is so friendly. I plucked up the courage to ask about building a robot vehicle, for complete novices, and was greeted with a reply practically the next day. It's really helped me with researching hardware for my robot.

It has also spurred my interest in and awareness of what people are doing in their free time. The country is filled with hacker communities working on big, ambitious projects, as well as parent-child teams spending their evenings together fiddling around and inventing wonderfully simple but oh-so-cool applications for the Pi.

I can't believe I didn't get involved sooner! I've missed so much and now I'm abso-blooming-lutely buzzing for my robot adventures. Smiley-face emoticon is required, me-thinks. :D

Anyhoo, the purpose of this post was to record a bit of terminology I've picked up over the past few weeks. It's kind of ESSENTIAL if you want to understand some of the convos on raspberrypi.org! These definitions are from motoman.com, my new dictionary-go-to:

Closed-Loop : Control achieved by a robot manipulator by means of feed-back information. As a manipulator is in action, it's sensors continually feed-back information to the robot's controller which are used to further guide the manipulator within the given task. Many sensors are used to feed-back information about the manipulator's placement, speed, torque, applied forces, as well as the placement of a targeted moving object, etc.

Compliant Robot: A robot that performs tasks, with respect to external forces, by modifying its motions in a manner that minimizes those forces. The indicated or allowed motion is accomplished through lateral (horizontal), axial (vertical) or rotational compliance.

Controller System: The robot control mechanism is usually a computer of some type (THE RPI), which is used to store data (both robot and work environment), and store and execute programs, which operate the robot. The controller system contains the programs, data, algorithms; logic analysis, and various other processing activities, which enable it to perform.


CPU (Central Processing Unit) : The main circuit board and processor of the Controller System.

Encoder: A feedback device in the robot manipulator arm that provides current position (and orientation of the arm) data to the controller. A beam of light passes through a rotating code disk that contains a precise pattern of opaque and transparent segments on its surface. Light that is transmitted through the disk strikes photo-detectors, which convert the light pattern to electrical signals.

Feedback Sensor: A mechanism through which information from sensing devices is fed back to the robot's control unit. The information is utilized in the subsequent direction of the robot's motion.

Robot Programming Language: An interface between a human user and a robot, which relates humans commands to the robot.

Servo-System: A system in which the controller issues commands to the motors, the motors drive the arm, and an encoder sensor measures the motor rotary motions and signals the amount of the motion back to the controller. This process is continued many times per second until the arm is repositioned to the point requested.

There is so much more, but this is just a taste of the lingo I promise myself I will learn, so that I can use it in my EPQ project and sound really awesome and fancy. Obviously, there is immense educational benefit to learning this but there is a small superficial motive as well...!

Sites used: http://www.motoman.co.uk/

Friday, 1 March 2013

Quick Note! Adafruit Industries

Adafruit.com, home to Adafruit Industries, sell a brilliant range Pi Accessories and also their own starter kit. It's £100+ but if I had that kind of money to spare, I'd buy it in a heartbeat. If you're interested, check it out here, looks very coool.

Sites used: http://adafruit.com/

Do I buy a kit? Or do I put together my own...?

I'm planning on purchasing my Pi this weekend, provided everything goes to plan. I'm not sure whether to order one from the original distributors, Farnell, only because the Pi website recommend them, or whether to buy a kit off Amazon or elsewhere.

I'm trying to find out what exactly I'll need to get started. The Raspberry Pi itself is not enough to really do anything, so I've found a list of 'necessary' additional items to purchase as well (necessary used here in the loosest way possible, mind):

- One SD card
- An SD card reader so you can write the OS image to your SD card
- A means of supplying power to the unit (an old phone charger will do). At the very least, you'll need a 5V micro-USB adaptor.
- An HDMI cable and HDMI-to-DVI converter if you're using a monitor instead of a HD TV. If you're just using a TV or a monitor that supports HDMI, you won't need an adapter.
- A USB mouse and keyboard
- An Ethernet cable

This list was found on engadget.com

With regards to the SD card, you can buy cards with the Raspbian OS loaded on already, so I think that's the best plan. But the mouse and keyboard... I'm not sure they are a priority; I have keyboards and a USB mini-mouse hanging about at home already, so if needed, I'm sure they'll do the job. I also own HDMI cables for things like Blu-Ray players and our PS3. HOWEVER, I definitely need a means of providing power so that needs looking into.

Maplin sells a Starter Kit for £74.99. A bit more money than I was intending on spending initially, but if I'm sure everything included will be of use, I am very tempted. It includes:

 AC-powered 4-port USB hub (useful)
▪ USB keyboard and optical mouse (already own)
 2.1A twin USB mains power supply (nice)
▪ 1.5m gold-plated USB A to micro B cable to power Pi
▪ 1.5m gold-plated HDMI cable (already own)
▪ N150 Nano W-Fi dongle for wireless connectivity! (I like this a lot)

And finally, good old Amazon, a handy little set (with Model B Pi) for just £52.50 (so far the most convincing):

▪ PCSL Power Supply
▪ HDMI Cable (already own)
▪ PCSL Special Edition Raspberry Network Cable
 8GB SDHC with Wheezy
▪ PCSL Special Edition Cherry/Clear Case

^ the HDMI will be an unnecessary purchase, and I would ideally like a Wi-Fi dongle, but the Model B Pi plus all of that is very reasonable! Now for a very long think...

Sites used: http://www.maplin.co.uk/raspberry-pi-board-and-starter-kit-652805
                 Amazon Starter Kit link
                http://www.engadget.com/2012/09/04/raspberry-pi-getting-started-guide-how-to/