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Oliver Hamilton
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https://pluspora.com/people/dec8b680adc8013646c5005056268def
https://pluspora.com/people/dec8b680adc8013646c5005056268def

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This weekend's project... IoT Audio Source Switcher!

With 4 stereo inputs and 1 stereo output this will be used to switch the input of an audio amp. Sources are switched using relays to avoid any cross-talk or other components leaking noise into the audio path.
I'm using an ESP8266 to control the unit and provide wifi access. Communication is handled using the MQTT protocol whereby clients can 'subscribe' and 'publish' messages to 'topics'.

The switcher subscribes to a topic e.g. "downstairs/kitchen/av". Other devices can publish to this topic "downstairs/kitchen/av" and include a message, this could be JSON encoded e.g. {"set": "source", "value": "2"}. Any device subscribed to this topic will receive this message and can process it accordingly.
I can publish to this topic from anything, an app, console, or another ESP8266. In one example I show a simple button press on another ESP8266 publishing a message to select the next source.

All the MQTT messages are handled by a local server or 'broker' running on a Raspberry Pi. The local nature of this 'IoT' means it doesn't rely on any external internet connections, third-party services or companies (https://www.telegraph.co.uk/technology/2018/10/12/glitch-yales-smart-security-system-sees-brits-locked-homes/)
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14/10/2018
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Any fans of the YouTube channel, Numberphile, will probably have seen their video from about a month ago called The Dollar Game. It's a graph based game where 'players' at the vertices of the graph have a balance. The objective is to get all the players/nodes out of debt by giving or taking 1 dollar from connected nodes. The original video (https://youtu.be/U33dsEcKgeQ) explains the game very well.

I thought this would make a neat game... so I put one together! It's a free Android app (https://play.google.com/store/apps/details?id=com.OlkhamSoftware.thedolargame).

The difficulty ramps up quite quickly, every level is solvable in at least one way. The levels are generated in a completed state then shuffled.
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Hopefully people will start to realise what a monumentally stupid idea it is to use solar panels as a road... Just take a look at these numbers, they're awful in every aspect.
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Big game hunters are prepared to travel to Africa and pay huge sums to hunt a dangerous animal.

I challenge them to hunt the most dangerous animal, these scum bag poachers. It may be close to the storyline of Hard Target (https://www.imdb.com/title/tt0107076/) but drastic measures are required.
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The award for awful chart/info-graphic this week goes to...

(https://www.bbc.co.uk/news/world-us-canada-45171311)
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Unfortunate timing and article ordering...
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I replaced the springs on the Mazda 2 today after finding one of them was cracked. It's quite straightforward but the part where you need a spring compressor to... well compress the spring so it'll fit in is pretty hairy.

I don't know what the spring constant of this particular coil was but I found values online ranging between 49-131kN/m and I estimate I compressed it by about 0.1m (10cm), as it's a small car I'll use k=50kN/m, that means there was about 250J of energy stored in the spring (E=½ k x²).

Which is only just shy of the muzzle energy from a .38 ACP handgun (https://en.m.wikipedia.org/wiki/Muzzle_energy)
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14/04/2018
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Took the Spark out for its first coastal flight today. I'm pretty happy with the performance so far.
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In a TVR... that was brave!

Plymouth man completes 20,000-mile pub adventure - http://www.bbc.co.uk/news/uk-england-devon-43056769
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