On the hard shoulder, of the wrong side of the road, they argued about whether the map really said that you could exit the Interstate from the left. And whether the entrance to our Holiday Inn would be clearly signposted. Meanwhile, my brother and I thought the baddies from The A-Team were going to machine-gun our car. There was much wailing and gnashing of teeth.

My parents didn't get divorced. But we also never took another driving holiday in a foreign country.

My wife and I are both a bit crap at reading maps. But our driving holidays have been... uneventful. Google maps has calmly told us when and where to turn. When our route has been unexpectedly blocked, it doesn't complain, but serenely re-routes us. From New York to New Zealand, we've been free to drive without arguing.

In truth, I've no idea how many divorces are triggered by someone NOT READING THE BLOODY MAP PROPERLY. But I bet that number has decreased since GPS became ubiquitous and affordable.

Technology has many unintended third-order effects.

The rise of YouTube means that I now know how to rewire a plug socket, reset my boiler, properly hang a shelf, and correctly replace a door handle. No more expensive calls to a handyman! But it also means I'm over-confident, and require people to come out and fix my mistakes.

Similarly, recipe sites and tutorials encourage even the most inept cook to make something fantastic. Perhaps this has led to a surge in takeaways when the Ortolan buntings drowned in Armagnac prove too complex for the amateur chef.

It is said that mandatory motorcycle helmets reduced the number of young male organ donors. While Uber has reduced drunk driving, WhatApp has increased distracted driving.

Every little piece of technology we create goes on to have a far stranger impact than we could ever imagine.

exiftool -c "%.2f" -TagsFromFile @ -GPSLatitude -GPSLongitude photo.jpg

(Thanks to the EXIFtool Forum for their help.)

Why is this useful?

Modern phones automatically attach a GPS location to every photo you take. GPS resolution is around 10 metres. When you share your photos, you're often sharing your precise location.

I wanted to upload some photos to the Wikimedia Commons of an interesting junction box installed in our home. I didn't want my home location stored on the Internet forever - but I thought it would be useful to include a rough location.

The above command takes a location of 51.123456,0.987654 and returns 51.12,0.98. That's good enough to roughly show the location, without revealing it exactly.

Fun fact! Your GPS won't work if you're above 18Km or going faster than 500 metres per second. Just in case you're a Soviet Guided Missile.

But if you're on a regular international flight, you should be just fine! Here are some screenshots I took using the open source GPS Test for Android.

Top tips: make sure you get a GPS lock and update your A-GPS data. It's also worth getting as close to a window as possible in order to see the sky without the metal shell of the aeroplane blocking you.

What a glorious sight! American GPS, Russian ГЛОНАСС, China's 北斗, Japan's 準天頂衛星 and the EU's Galileo. I was asleep when we went over India, so I don't know if my phone would have picked up NavIC.

The sky view is particularly beautiful.

I also found a page on British Airways' inflight WiFi which showed what the plane itself was reporting.

My cheap phone and the multi-million pound plane disagree slightly on speed and height. But not by much!

I was also able to take these geo-tagged photos of Australia from the plane.

Sydney

Desert

So, next time you're on an international flight, take a peek at the sky!

Essentially, OBD (On Board Diagnostics) is a port which is found on every car produced since the late 1990s. It allows garages to see all sorts of diagnostic information about your car, its engine, and all other manner of petrol-headed goodness. It's designed to be easily accessible and conform to a common standard.

So, it's no surprise that a whole cottage-industry has developed around this port. Whereas connecting to OBD used to be something done only by garages, now anyone can buy an adapter. Which is how I got this £20 BlueTooth capable OBD dongle.

After scrabbling around in my new Toyota Yaris Hybrid, I found the OBD port just to the right of the steering wheel.

Fitting it was simply a matter of figuring our which way round it went, and then jamming it in. It fits well and doesn't feel like it will fall out - but a bit of gaffer tape may be in order to secure it when I drive along bumpy roads. As soon as it plugged in, the lights started flashing and I was able to pair it with my Android phone.

Security

The default code for these things is either "0000", "1234", or "6789". I really wish that could be changed. OR, at least, print a unique 8 digit code on each device. Essentially, the unit is on all the time - slowing drawing energy from the battery - which means that it is discoverable all the time.

So, anyone walking around the car park - or stuck in traffic with me - can get a full readout of my car's diagnostics.

True, it's not the biggest security threat in the world. We know that proprietary software is riddled with bugs. Toyota had to recall hundreds of thousands of cars due to software glitches.

Perhaps there's a bug in the car - or the device - which will let an attacker stall the engine, or unlock the doors, or find out my fuel efficiency.

Of course, I could unplug the dongle every time I get out of the car (some units have physical power buttons) but that's a faff I can do without.

The Plan

I'm using the free Android app Torque (Pro Version available for £3).

It's a nifty program which lets you monitor (and export) data from the engine. My phone will quite happily pair with the car's audio system and the OBD dongle - so that shouldn't be a problem. But it does rely on my remembering to pair the device (and take my phone with me!).

What I'm planning to do is use a cheap 2nd hand Android phone to act as a 3G bridge for the dongle. The Yaris has a USB port hidden in the glove compartment - it's usually used for playing music from a USB stick, but I think it should be sufficient to trickle charge a phone.

As the car doesn't have a built in GPS unit, I can use the Android's GPS to keep track of the car. I can use its 3G connection to email or text me whenever the car is moved - useful if it's being stolen or towed. I can plot my journeys, automatically let my wife know when I'm stuck in traffic, and all sorts of other jiggery-pokery.

Let the hacking commence :-)