Accessories, Programming, Reviews, Robotics

4tronix Agobo review – a cheap, hackable robotics kit for the Raspberry Pi

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Gareth from 4tronix was kind enough to send me one of these to review and say what I like about it.

Introduction

The 4tronix Agobo is a robotics kit for the Raspberry Pi model A+. It comes as a kit which requires assembling, but not soldering (although you can do some). You can see the contents in the picture below: the main board (with attached motors), 2 wheels, a battery pack and cable, a castor kit and various fixings. The low-powered model A+ is ideal for robotics and this kit takes advantage of its tiny size – the whole thing when assembled is itself very small and it’s just the sort of kit to get children excited about electronics and programming.

The main board itself (shown below in close-up) has attached infra-red line sensors on the underside, the previously mentioned motors, plus headers for serial, I2C and also a header at the front of the board specifically designed for an ultrasonic distance sensor. There are also two (very bright) white LEDs which are controllable in software, plus a “mode” button. All this connectivity on the board is fantastic as it saves you having wires all over the place. There is also a break-out for the entire GPIO. This comes in useful with the optional prototyping plate that you can buy as it plugs directly into that (with some soldering needed). There are some small prototyping areas in the middle of the board with GND, 3v3 and 5V rails. At the rear is the microUSB power port which means you are delivering 5V directly to the board as well as to the Pi. The circuit board is of very high quality and the silk-screening is superb, which means everything is clearly labelled.

Overall, I really must commend Gareth on his design – he’s clearly taken a lot of time and thought over it.

Assembly

I chose to assemble the kit with the optional prototyping board, the PlusPlate. This board fits over the top of the rest of the kit and allows you to wire on additional components. There are some fiddly moments involved in putting it together. The ball castor assembly requires you to hold it together while you screw it to the board. This can result in ball bearings and screws going all over the place and there’s definitely a knack to doing it. I’ve since spoken to Gareth about it and, until they figure out a better way, they are going to glue the assembly together which should make it a lot easier.

The assembly instructions are excellent – perhaps for the more difficult builds (those including the prototyping plate) there could be some extra photographs to help you work out which screw/fixing goes where, but to be honest that’s half the fun and challenge of putting it together. I only swore a few times 🙂

The soldering that I had to do (which is only necessary when dealing with the PlusPlate) was simple enough – two male 40-pin headers and one female 40-pin header is all that’s needed.

Here is the robot all assembled (without the tubular battery pack) so you can see what you end up with. From this picture you can clearly see the Neopixel attached to the prototyping board, which is there for no other reason than added blinkiness, as far as I can tell! The PlusPlate is, again, of very high quality and is clearly labelled with power and ground rails.

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The nice thing about using the PlusPlate with the kit is that it means the HDMI port is available for use. This isn’t the case when the PlusPlate isn’t used as the battery holder obscures the port. This could be a little annoying if you’re trying to program the A+ and you want to be able to use a screen as it more or less forces you to use a wireless dongle or serial cable to do so, or do as I did and keep swapping the SD card between the A+ and a B+ that is wired to the screen/keyboard. The build does leave the USB port free so it means you can plug in a wifi dongle or keyboard. I would recommend building it with the PlusPlate – you can just about use the HDMI port and still power up the Agobo (the socket is almost obscured by the HDMI cable I was using).

Software

The website for Agobo contains a download link for some demo software that will show you how to program your robot. The demo software package contains the following:
  • The main library (which obfuscates a lot of things to do with turning GPIO pins on and off).
  • A motor testing script that takes input from your cursor keys and makes the robot move in that direction.
  • A script to test the line sensors.
  • A script to test the ultrasonic distance sensor.
  • A script to flash the white LEDs on the main Agobo board.
  • A script to test out the Neopixel on the PlusPlate. (In order to use this script, you’ll need to install a Python library which is available on Adafruit’s website).

Here’s a video of all the scripts being tried out:

I found all the software to be of the highest quality, with plenty of comments to help you get your head around what the code is doing. You shouldn’t have any problem, with a little time, putting it all together into a fully-featured program. Gareth is going to do some more tutorials on things like getting your program to run on boot-up so keep an eye out for those.

Pricing

The best thing I can suggest for pricing is to head on over to 4tronix’s store and take a look. The base model is £24.95 plus VAT and delivery. There are lots of options, though, including buying a Raspberry Pi model A+ in the bundle. If you went for the whole package, including the A+, the acrylic plate cover, the PlusPlate, the console/debug cable, a wifi dongle, an SD card and an ultrasonic sensor, it comes to £75.84 including VAT and delivery. I would strongly recommend going for a package with the PlusPlate as it gives you that much more flexibility and hackability.

Conclusion

The Agobo is simply a terrific product and it’s got a great price attached. The base model is just under £30 including VAT, and you really can’t go wrong with the quality on offer. Assembly is fun, if a little fiddly (but then where’s the fun in making it really easy?) and the enclosed software is top-notch.
So, who would I recommend it for? Well, to be honest it’s an ideal platform for anyone due to the flexibility of the kit, especially if you build it with the PlusPlate. I can imagine it being really popular with schools, due to the low price tag and small size. It’s also an ideal kit for parents to build with their kids. There’s a bit of physical work to do, which is the start of the learning process, plus you get a lot of help with writing the software. The inbuilt line sensors and space for the ultrasonic means that it’s perfect for autonomous use as well as remote-controlled operation.
Really, really well done 4tronix. Highly recommended.
GPIO boards, Programming, Software

New version of ScratchGPIO for the Raspberry Pi released

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Simon Walters has announced the release of version 7 of ScratchGPIO, the brilliant version of Scratch that enables you to use the Pi’s GPIO pins. According to Simon, the new version contains:

  • Background engine room stuff
  • Support for the PiAndBash I/O board and the Agobo robot from 4Tronix
  • Various bug fixes

Find out how to download and install ScratchGPIO by visiting this page.

GPIO boards, Programming, Tutorials

Pi & Bash tutorials released for the Raspberry Pi

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A few days ago, I published a review of the Pi & Bash add-on board for the Raspberry Pi. Rob Boyle, who created the board, has been in touch – he’s started writing coding tutorials for the P&B and I thought I’d share them with you. These tutorials are great – they show you how to do simple things with the board and clearly explain the code that you need to add to get results. So, here is a list of the tutorials so far:

If you’ve got one of these boards, or are thinking about getting one, take a look at the tutorials as they’re well-explained guides that will help you understand what is going on and will help you get started on your own projects.

You can get hold of a Pi and Bash from ModMyPi or RyanTeck.

Crowdfunding, GPIO boards

ProtoCam+ for the Raspberry Pi – final hours on Kickstarter

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This is just a quick blog post in the form of a ‘shout-out’ for Richard Saville’s ProtoCam+ Kickstarter. It’s now entering it’s final 30 hours and is already 173% funded.

The ProtoCam+ is a great prototyping board for the Pi. It’s HAT-sized and plugs directly onto the GPIO pins of model A+ and B+ Pis. It has a large prototyping area which surrounds a mounting for the camera module. This means it is ideal for adding circuitry to your camera project. You could, for example, create a camera with it by adding LEDs for a flash and a button for a trigger. Or you could add sensors to detect changes in light or movement and take a photo when certain conditions are triggered.

I’ve got one of these boards myself (Richard was kind enough to send me an early one) and it’s very high-quality and well laid-out.

The board costs £7 from Kickstarter and you can make your pledge here.

Competitions, Education, Outreach, Science

AstroPi officially launched at BETT – send a Raspberry Pi to space

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astropi

At the BETT education conference in London last week, the Raspberry Pi Foundation officially launched the previously announced Astro Pi competition. Astro Pi will involve the launch of two Raspberry Pis into space with astronaut Tim Peake. Tim will take the Pis and SD cards onto the International Space Station where they will be set-up to carry out experiments submitted by schools. This is truly a unique opportunity for schools and I hope as many as possible submit their ideas and code for consideration. There are Primary and Secondary categories up for consideration – the first deadline for both is 3rd April, so get cracking! You can read more about Astro Pi on their (very nicely done) website here.
Accessories, Games, Geeky Techiness, Programming, Robotics, Tutorials

Raspberry Pi Wifi-Controlled Cat Laser Toy

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PLEASE READ THE NOTES OF CAUTION BELOW

I wasn’t going to feature this and then I thought I would with a note of caution.

Here’s an Adafruit tutorial in which you construct a remotely-operated laser-pointer cat toy. The project provides a web interface which you can use to control the laser pointer which is attached to a couple of servos for positioning.

Here’s the note of caution: They say not to shine this in the eyes of humans or animals – indeed, you should never shine a laser in any eyes – it’s bloody dangerous! While this is relatively easy (not foolproof) to avoid if you’re holding the pointer in your hand, it’s not so easy to guarantee it if you’re relying on a web interface with a streaming camera. So, please do this in the knowledge that it could be a bit dodgy! :-/

Read the Adafruit tutorial here or view the video below.