Budget robot kit for the #RaspberryPi just launched

Ryan Walmsley, creator of Rastrack and co-editor of Pi Weekly (and constant CamJam attendee!), has had a great success with his RTK motor controller board and has now branched out into a full beginners robot kit. The kit includes almost everything you need to get a robot up-and-running:

  • A RTK motor controller board kit
  • A chassis
  • A wi-fi adapter
  • A battery box for driving the motors
  • 2 motors and wheels
  • Wires to connect it up and screws to assemble it
  • Lots of documentation and code

He is running the kits as an Indiegogo campaign and so you have some options:

  • £33 – the kit with a motor controller board you’ll have to solder yourself
  • £35 – the kit with a soldered motor controller board
  • There’s also a 5-robot set available for schools at £148 (which is quite a saving).

For the first ten he sells, there’s a £3 discount on the basic kit so you could pick one up for £30.

The only things you will need to get yourself are: a Raspberry Pi, batteries for the motor pack and a portable power source for the Pi. Ryan’s decided not to include these as shipping of batteries carries with it a load of regulations and possible extra charges.

You will be hard-pushed to find a better kit at a better price. The quality is good and has been fully tested by Ryan.

Go and get one now if you want to get into robotics!

I’m not affiliated to Ryan or his business, I just think this is a great kit at a great price and I like to support new business where I can.

Wolfson audio card now available for the #RaspberryPi

As previewed on this site in November, the Wolfson Audio card for the Raspberry Pi is now available from Element 14. It has the following features:

  • 3.5 mm jack (4-pole) for a headset/boom mic combination for gaming or VoIP applications
  • 3.5 mm jack for microphone input
  • On-board MEMS microphone
  • 3.5 mm jack stereo line input for connection to devices such as digital audio players (iPod etc.) or mobile phones
  • 3.5 mm jack stereo line output for connection to devices such as external stereo amplifiers or powered speakers
  • S/PDIF input and output
  • On-board class D power amplifier for external speakers, with connection to external power source if needed.
  • Small pin header for extra functions if they are low cost, already on-chip, and don’t require any further components
  • Raspberry Pi form factor

It’s currently available for £24, which isn’t at all bad for this quality of kit and is only compatible with Revision 2 Pis – the ones with the extra P5 pads. You don’t need to solder a header onto the pads as the card uses an ‘innovative sprung’ mechanism to connect to the pads. (I’m not sure what that looks like in practice, but it sounds like a very cool, and sensible, way of getting around the P5 header dilemma).

#RaspberryPi for Dummies – book review

9781118554210.pdfRaspberry Pi for Dummies was sent to me by Wiley for review. So here goes!

Written by Sean McManus and Mike ‘Grumpy Mike’ Cook, Raspberry Pi for Dummies is a comprehensive look at setting the Pi up, administering it, using it as an office machine, using it for programming and using it for hardware hacking.

It’s written in an easy-going (occasionally anarchic) style which fits in with all the other ‘Dummies’ guides that are out there. This book has personality and it’s easy to like the style.

To start with, the Pi is introduced and the hardware discussed. I particularly liked the section on it’s limitations as this is essential information to grasp if you are to use your Pi to it’s limits. Following that, there is a description of downloading and flashing an operating system to your SD card. This is now out-of-date as the best way of getting the OS onto your SD card is now to use NOOBS, but the information is still accurate if you want to do it manually. After that, the writers take us through the various peripherals you need to plug in to take your Pi from being an attractive circuit board to being a fully usable computer. I was disappointed that there wasn’t mention of how to connect to a VGA monitor (which is a not-uncommon problem) using an adapter. They also do not cover connecting to a wi-fi network, which is a shame, as some homes do not have their router in a suitable location.

The next part covers using Linux both via the desktop and via the command line. The Linux shell section is particularly good here and covers all the commands you’re like to want to use in day-to-day operation. There’s lots of info about file management here, which is good to see.

The next part is about using the Pi for “work and play”. This section covers using a couple of software packages: LibreOffice for basic office work and GIMP for image manipulation. This is useful as these two activities are the most common when using a computer, so it’s worthwhile having them there, if only so people can understand the analogue between something like Microsoft Office and the package you’d use on the Pi. After that, the book takes you through creating a website with the Pi. This is the first time you’re asked to do something creative and seems slightly out-of-keeping with the purpose of the Pi. However, it’s pretty comprehensive and does delve into the HTML to help you understand it. The book then continues into installing and using RaspBMC to play audio and video on the Pi. Again, this feels slightly odd. I would’ve preferred to have seen how to play video and audio through the normal desktop interface that you’d already been introduced to.

Part 4 covers programming in two flavours: Scratch and Python. Programming concepts are introduced and there are fully worked examples for both languages. I particularly like the section in Scratch which deals with fixing a ‘bug’ – a great skill for every programmer to have. The Python section is good and again introduces programming concepts before moving onto the example scripts. Pygame is also covered here and there’s a great Breakout example game to type in and follow.

Part 5 is titled “Exploring Electronics with the Raspberry Pi”. There is some great fundamental electronics information here and you are introduced to concepts such as resistance, current etc. The GPIO pins are introduced and described so that the beginner can understand what those ‘sticky up bits’ are. There is also a very good section on soldering here – very good for the beginner, though more pictures might have helped. However, I would have preferred much more breadboarding electronics here – I think the authors have missed a trick by delving so quickly into soldering. While it’s true that most electronics projects result in needing to solder, it is also true that most projects start out on breadboards and they could have spent much more time on that medium before moving onto more permanent circuits. This part of the book then moves onto creating a fully-fledged project. It seemed a bit quick to me and again, the lack of prototyping shows here. I would like to have seen something like the Pi Cobbler be used with a breadboard showing how most people start out. Whereas the beginning of the book could be understood by young teenagers, I think by this point in the book it would take an adult to get to grips with what they’re talking about. Then next bit deals with using the GPIO pins more extensively and then moves onto capturing analog inputs. This is quite advanced stuff now and I wonder if it isn’t perhaps too complex for a ‘Dummies’ book. I was particularly surprised to see a “surface mount” component in use. Remembering that the reader has probably only started to solder, surface mounting would be way beyond their capabilities.

The final part of the book is “The Part of Tens” which is a standard fixture with Dummies books. In this Dummies book, the writers cover 10 “great software packages” and 10 “inspiring projects”. The inspiring projects bit is particularly good as it leads the reader to blogs where they might find additional projects as well as the 10 featured.

There are two appendices. The first is a troubleshooting guide (in which ‘change the power supply’ is surprisingly near the end of the basic steps list) and the second is a list of the GPIO pins and what functions they perform. As expected, there is also a comprehensive index.

In conclusion

There are a few flaws with the book – my main issue being with how quickly it gets into complex circuitry and soldering concepts. That’s not to say the information is wrong or inappropriate – but the speed of the book in this part accelerates too quickly in my opinion. I wonder if this book might be better off in the hands of parents with Pis rather than children.

Having said that, the other parts of the book more than make up for any ‘scare factor’ that the complex concepts might provoke. The basic maintenance, productivity and programming sections are excellent.

So, a mixed reception for this book, but not an overtly negative one. I must score it a solid 7/10.

Focus on Education @ the Cambridge Raspberry Jam – 10th May

Come along and listen to a variety of talks and presentations centring on the new Computing curriculum and how it affects schools at both Primary and Secondary level. We will explore the challenges of the new curriculum, what resources there are available to teachers and other educators and see how the Raspberry Pi can help to deliver results in the classroom.

You will also be able to to see young people, and older people, use the Pi in practical workshops.

Focus on Education is being run as part of the Cambridge Raspberry Jam and will take place on Saturday 10th May between 12pm and 6pm at The Institute of Astronomy, Madingley Road, Cambridge. Tickets are £3.50 each.

To register, please use our EventBrite page. If you have any questions, please don’t hesitate to ask!

BerryClip+ for the #RaspberryPi review

Matt Hawkins (aka The Raspberry Pi Spy) sent me one of his new GPIO add-on boards for the Pi called the BerryClip+.

The BerryClip+ is a simple, half-sized add-on board for the Raspberry Pi that plugs straight onto the GPIO header. It contains 6 LEDs (2 red, 2 amber, 2 green), 2 momentary push buttons and 1 buzzer. It is an improvement over the original BerryClip in that it has an extra button and also breaks out the majority of the GPIO pins to a separate header. You can watch a review of the original BerryClip on the Raspberry Pi IV Beginners YouTube channel.

The Original BerryClip

The BerryClip+

As with the original BerryClip, the BerryClip+ comes as a kit. The kit contains all the parts you need and a card listing the bill-of-materials and links to some help. I would like to have seen explicit mention of the test scripts that you can download on the card, but if you end up on the instructions page then you’ll find these soon enough.

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As a kit, it means getting your soldering iron out. I found that the BerryClip+ was slightly more difficult to solder together than the original. This is mostly because of the extra male header pins which restrict the space you have to solder on the 26-way header. It’s not a major issue, though, and really it just needs a steady hand and some patience. One thing I should say is that because of the way the rest of the components are placed and spaced, this is an ideal project for the soldering beginner. Here’s a picture of my soldering efforts with all the resistors in place:

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And here’s a couple of photos of the finished board. The whole thing took about 30-40 minutes, but I really take my time and a more experienced solderer could probably do it in 20 minutes.

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And here’s the board plugged into my red Pi:

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The BerryClip+, just like the original, can be tested out using a series of example scripts downloadable from bitbucket. Instructions for doing this can be found here.

There are twelve scripts in all plus an added bonus, of which more later. The twelve scripts are as follows:

  • berryclip_01.py – Test LEDs only
  • berryclip_02.py – Test Buzzer only
  • berryclip_03.py – Test Switches only
  • berryclip_04.py – Test LEDs and Switches
  • berryclip_05.py – Test LEDs, Buzzer and Switches
  • berryclip_06.py – LED sequence
  • berryclip_07.py – Dice Simulator
  • berryclip_08.py – Reaction time game
  • berryclip_09.py – Random LEDs
  • berryclip_10.py – Multiple LED sequences in a loop
  • berryclip_11.py – Traffic light simulator
  • berryclip_12.py – Morse code generator

These scripts are terrific and really add value to the board. They introduce the board’s basic GPIO functionality and also show you how to do multi-threaded event listeners so that, for instance, you can run a sequence on the LEDs but ‘listen’ for a button press at the same time. Basically, anything simple that you’d want to do with the board can be found in these scripts. Also included is a ‘horse racing’ game written by Jim Flewker (which I previously covered here) which is an interesting example of what you can do with the board and a little imagination. I should say that the download instructions provided on Matt’s site worked flawlessly – exactly what is necessary when you’re providing code (and something other people could learn lessons from – make it easy, make it work).

So what is my overall opinion of the board? Well, it’s very good. For £6.99 (compared to £5.99 for the original) you get a decent number of components plus the circuit board plus the scripts. It’s a very good value board and can be compared favourably alongside, say, the Pibrella (which is £10, pre-assembled and has a Python library but has fewer components and is slightly easier to plug things into with the female header). Matt’s board gets points for the extra switch, especially, as you can really make some great interactive activities with two buttons, and breaking out the remaining GPIO pins means that it’s easily extendible if you want to add more LEDs, buttons and buzzers (for instance).

Matt’s done an excellent job making a cheap, accessible board that could easily be used both at home and in classrooms (soldering notwithstanding, but there’s always some enterprising techie in school to do that).

Overall rating: 9/10

You can purchase a BerryClip+ from Dawn Robotics or ModMyPi (plus £2 delivery). The original is also available from those re-sellers.