Update: source is available on GitHub including some basic image processing stuff.

The IOIO  is a small circuit board with a USB socket, a microcontroller and 48 input/output pins.  Plug it into an Android phone and you can use software to write to or read from each of the pins. Roughly speaking, on is 3.3V and off is 0V. Some of the pins can also function as analogue inputs and PWM outputs.

I initially looked at Arduino but in the end IOIO made more sense for a number of reasons:

• Pure Java API – no new languages to learn
• USB built in – Arduino controller would need a USB host shield to communicate with the phone
• Cheaper than Arduino + USB shield
• More IO pins than I could ever need

In theory, the IOIO board works with any Android device. In practice, there are many phones it doesn’t work with. The first phone I bought had to be returned to the shop and the second phone only worked after upgrading it to a non operator branded version of Android. On the other hand it worked straight off when I tested it with someone else’s Nexus One and HTC Desire.

Hardware

The first step was to dismantle the tank and strip out the internal RC circuit. That left only the tracks, drive motors (and gears), battery and on-off switch. Sadly that meant losing the BB gun in the turret. There’s always a next time.

Due to current draw issues, I couldn’t just connect the tank’s motors to the output pins of the IOIO. At best it would not work, at worst it could fry the circuit. I bought a TB6612FNG motor driver circuit which controls two motors using a PWM channel and two digital channels per motor. It connects directly to the battery to provide up to 1A current to each motor. I was initially worried about damage from back-EMF but so far that hasn’t been a problem.

The final pieces of equipment were a set of header pins to solder into the IOIO and TB6612 and a solderless breadboard to make it easy to reconfigure the circuit if necessary.

In the photo above:

• The black and yellow wires, centre right, are 10V and ground from the battery (via on-off switch)
• The black and red wires, top and left, go to the motors
• The blue wires are carrying 10V from the battery
• The yellow and green wire is carrying 3.3V from the IOIO to drive the TB6612 chip
• The brown wires are ground
• The TB6612 and IOIO control pins are connected through the breadboard

Software

I’m still not sure what this robot will ultimately do but an obvious first step seemed to be to make it remote controllable over the internet.

This is my first Android project but thankfully the Android SDK and documentation are outstanding. With the help of a few tutorials I went from Hello World to a simple app that accepted HTTP connections in just a few hours.

I now have a basic HTTP server on the phone which serves up a single web page and then listens for commands sent from that page over AJAX. Sending real time commands over HTTP is tricky because of the overhead in setting up TCP connections and the fact that requests may arrive out of sequence. I got around the first problem by using HTTP 1.1 persistent connections and the second by including a counter variable with each request. Any request with a counter value less than the last one received is ignored.

Using multiple threads on the phone to handle each incoming request, I’ve got response times over wifi down to around 30ms which is good enough. I’ve not yet tried it over 3G but I suspect network latency may be a big problem.

I looked into using UDP instead of TCP to send the commands as that’s what RTP uses. However there’s no way to send UDP packets from JavaScript and I didn’t want to have to use Flash or Java on the client side.

Next

Likely next steps are:

• Stream video from the camera to the browser so I can drive it from another room (or country)
• Improve the input UI to make it easier to drive
• Implement some basic machine vision algorithms such as line following or the classic photovore behaviour (drives towards light)

• Add a laser line to the front to make a budget laser rangefinder
• Let other people control it over the internet
• Use the Android text-to-speech and the phone screen to give it a voice and a face
• Hook it up to a thermal receipt printer and make it physically deliver my emails
• Implement a behaviour-based robotics API with swappable behaviours
• Foster a community of robot builders using the same API to create a pool of behaviours which can be combined to generate highly complex robot personalities
• Skynet

This passage about the equivalence, from a worker’s perspective, between new technology and free trade particularly caught my eye:

Economist David Friedman observes, for instance, that there are two ways for the United States to produce cars: they can build them in Detroit or they can grow them in Iowa. Growing them in Iowa makes use of a special technology that turns wheat into Toyotas: simply put the wheat onto ships and send them out into the Pacific ocean. The ships come back a short while later with Toyotas on them. The technology used to turn wheat into Toyotas is called ‘Japan’, but it could just as easily be a futuristic biofactory floating off the coast of Hawaii.

Jobs may be lost when new technology or cheaper imports make old production methods obsolete. But, since there can be no imports without exports, jobs are also created. On the whole everyone is better off, even if some end up having to retrain.

Dear Meg Hillier, 

I am concerned by the great potential for misuse presented by the anti-terrorism legislation introduced in recent years. It is an issue that has worried me for some time but I have been moved to write to you now after hearing the topic raised in parliament today.

The latest cause for concern is the use of the Counter Terrorism Act 2008 in restricting the public’s freedom to take photographs featuring police constables. The act contains the clause “[photographs] of a kind likely to be useful to a person committing or preparing an act of terrorism” and yet, after barely a month of the law being in force, there are already reports of abuse. One such report involves an elderly man being intimidated into deleting an image in which a police car was visible parked on double-yellow lines.

But the larger issue is the multitude of wide-reaching powers being granted to the police force under the banner of anti-terrorism in what I believe to be a climate of fear and unwarranted hysteria. One such power is the much publicised 28 day detention without charge but there are many others of equally questionable validity. Not only am I vehemently opposed to any extension of the 28 day period but I believe that 28 days is already too long and must be reduced. We are assured that these laws are necessary for our safety and will only be used against extremists, yet time and again we see the same laws being abused and misused.

During the Heathrow Climate Camp in August 2007, for example, it was widely reported in the media that police had been briefed to use laws introduced under the Terrorism Act 2006 against the protesters. The attempts to justify this by claiming that the assembled environmentalists presented a terrorist threat were laughable.

It is not possible to introduce legislation to be “used only against terrorists”. The police, by definition, do not know if a suspect is a terrorist at the time he or she is detained, or else an extended detention period would not be required. So who gets to decide when counter terrorism laws are applicable? It’s only a small leap of the imagination from here to an Orwellian reality in which losing your freedom is just one wrong thought away.

I am sympathetic to the police’s cause and I understand that investigators want more time in order to do their work to the best of their abilities. But I challenge you to show me any professional who does not believe they could do a better job if only they were given more time in which to do it.

While the events of 7th July 2005 were undeniably tragic for the friends & relatives of those who lost their lives, it is worth keeping a sense of perspective. In the UK, more people are killed in traffic accidents every week than have died in terrorist related incidents in the past 10 years. If we, as a society, are not willing to give up the convenience that cars afford us, then how can we justify giving up our human right to freedom?

Yours sincerely,

Tamlyn Rhodes.

This is probably the political issue I feel strongest about right now. These laws scare me far more than the terrorism they are meant to protect me from. And yet i feel pretty powerless to do anything about it.

For now, writing to my MP will have to do.

Dear Ms Rhodes

Thank you for writing to us on 13 November 2008. We realise how important it is to provide a quick response, particularly if you have had a bad experience.

Although we aim to respond in 5 working days, you will definitely receive a full response within 20 working days of us receiving your letter.

Yours sincerely

Carol Payne

I was mentally composing a response along the lines of:

Dear Mr Payne

I am writing to you to confirm that I have received your letter confirming that you have received my letter. Although I aim to respond in 5 working days, your letter appears to be a waste of everyone’s time and, as such, not deserving of a response.

However this morning I received 4 vouchers for £5, £10, £5 and £1 so I probably won’t bother.

National Express, on the other hand, have yet to reply to any of my letters.

It’s essentially a notice of price increases but instead of simply stating the new unit price, Dale Vince (Managing Director of Ecotricity) attempts to explain the global economic forces behind the increase. After mentioning the growing demand for fossil fuels from the developing world and how the rising prices are exacerbated by the futures markets, he explains why a green energy supplier should be affected at all:

I know that it can seem counter intuitive to some of our customers, that we should be affected by rising prices for fossil fuels. But until we generate the majority of our own power from green sources we will remain affected by the ‘market’ and the same is true of the UK as a whole.

The tone of the letter is really honest, and does not shy away from admitting the company’s weakness:

Our policy, indeed our promise, is to match exactly the price of the Big Six in each area, and so we need to raise our own prices. But this is not just a matter of policy and we won’t be adding to our profits from this. It’s a matter of necessity that we raise prices to match our increased costs.

For the last few months we have been absorbing significantly higher costs. Following EDF’s price increase now will allow us to restore our position. Quite honestly, we could not have gone for many more weeks without raising prices, even if EDF had not.

It’s stuff like this that makes me love my electricity supplier – and that’s probably not a phrase you’re likely to hear very often!

• A copy of Grazia from 2007
• An A1 size poster for Prison Break
• A sock
  
• A piece of wood
• One and a half UK road atlases
• An empty bottle of Ribena
• A 33cl bottle of Vittel
• A jar of Sainsbury’s sugocasa best before August 2008
• Three golf clubs (wedge, 9-iron, putter)
• Four golf balls
• Three and a half golf tees
• A tent peg
• A toothbrush
• Two pairs of sun glasses
• An old-style Nokia charger (the cigarette lighter socket was stolen with the CD player)
• Various vacuum cleaner attachments (but no vacuum cleaner)
• A camping stove
• The lock from someone’s front door
• A key (which doesn’t fit the lock)
• A 50 drachma coin
• Some kind of sherbert in a lemon-shaped plastic container
• A scarf
• A blanket
• A picnic blanket
• Duran Duran collectors edition CD (free with the Daily Mail)
• A plastic foot

But, just for fun, lets look at those stats a little closer…

The first thing you’ll notice is that it isn’t to scale. The 10% arrow is much thicker than 5 of the 2% arrows and the 32% one is only a little wider than the 10% arrow.

The numbers from the six categories add up to 100% implying that those six icons represent all greenhouse gas emissions. So the car presumably means all road transport (what about trains & boats?) The factory must represent industry? The trees are deforestation and forest fires and the like (does that include farming?). The plug is power generation. And the cloud is… fuck knows. Miscellaneous? The weather? Bad thoughts? In that context, 2% of global emissions coming from a single industry suddenly seems like quite a lot. Indeed, it is about as much as that generated by all human activity in Africa!

It appears that the 2% figure quoted comes from an Intergovernmental Panel on Climate Change report which is undeniably a reliable source. However that report is from 16 years ago during which time the volume of flights has skyrocketed (no pun intended).

Also very importantly it doesn’t take into account the fact that because the greenhouse gases from flying are released high in the atmosphere, they are 2 to 4 times more damaging than the same gases released at ground level. Nor does it consider that the water vapour produced by aircraft leads to the formation of cirrus clouds that also contribute to global warming. Indeed, carbon dioxide accounts for only a third of aviation’s impact on the atmosphere.

But in the end, even if aviation’s impact on global warming really was that small, why is that a reason not to try and reduce it?

• Festo AirJelly – a flying jellyfish airship thing. Very calming.
• Clock Sculpture – 150 separate hands that rotate to spell out the name of the current hour
• One Day Poem Pavillion – holes drilled in the ‘pavillion’ form patterns on the floor which spell out a different poem every hour
• Do web sites need to look exactly the same in everybrowser? – unambiguously answers one question
• Lip Dub Stars – turn up the volume for this one!