Wednesday, 15 March 2017

How to Teleport Schrödinger's Cat

Support me on Patreon: Previous video on No Cloning: How to teleport Schrödinger’s cat: this video presents the full quantum teleportation procedure, in which an arbitrary qubit (spin, etc) is teleported from Alice to Bob by way of a pair of particles entangled in a bell (EPR) state and the transmission of information via a classical channel. Thanks to everyone who supports MinutePhysics on Patreon! Link to Patreon supporters here: REFERENCES: No Cloning video: The No-Cloning Theorem: MinutePhysics on Schrödinger’s Cat: The History of Schrödinger’s (& Einstein’s) Cat: Original Quantum Teleportation Paper: Wikipedia on Quantum Teleportation: Calcium ion teleportation: Teleporting a 2-qubit state: Multi-level teleportation: Scott Aaronson blog post on Teleportation (& Free Will, etc): Classical Teleportation: Blog post on quantum vs classical teleportation: MinutePhysics is on Google+ - And facebook - And twitter - @minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich Music by Nathaniel Schroeder
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Wednesday, 14 December 2016

[BONUS VIDEO] Chill Out Edit - 1000 Hours in 12 Minutes

Chill Out Edit - 1000 Hours in 12 Minutes, by Clickspring All footage sourced from the long term project "How To make a Clock In The Home Machine Shop": Part 1 - Making The Frames Part 2 - Machining The Pillars Part 3 - The Washers And Screws Part 4 - Cutting The Wheels Part 5 - Cutting The Pinions Part 6 - Crossing Out The Wheels Part 7 - Making The Barrel Part 8 - Making The Barrel Arbor Part 9 - Chapter Ring Part 10 - Bezel Part 11 - Bezel Screws Part 12 - Collets And Other Arbors Part 13 - Planting The Train Part 14 - Barrel Click And Clickspring Part 15 - The Dial Assembly Part 16 - The Motion Work And Hands Part 17 - Regulator & Suspension Post Part 18 - The Pendulum Part 19 - Making The Legs And Base Part 20 - The Crutch Assembly Part 21 - Mainspring And Escapement Part 22 - The Stopwork Mechanism Part 23 - The Key, Polishing & Assembly If you would like to help support the creation of these videos, then head on over to the Clickspring Patreon page: ________________________________________________________ A very special thank you to Patrons Dan Keen, Samuel Irons, Sean Kuyper and Mark Kobey ________________________________________________________ Ask Me A Question: Follow Clickspring: Chill Out Edit - 1000 Hours in 12 Minutes, by Clickspring
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Monday, 14 November 2016

Data & Picard | Pogo

A remix of Star Trek: The Next Generation. Details below! Listen on SoundCloud: Temba, his arms wide! In Tamarian this signifies the giving of a gift, first heard in the excellent episode Darmok. Data & Picard is my tribute to one of the greatest TV series of all time. It is an original track featuring the voices of Captain Picard (Patrick Stewart) and Commander Data (Brent Spiner), accompanied by a music video I shot entirely in my living room with a green screen and lights. The track opens with the Klingon Victory Song, followed by a remix of Data singing Che Gelida Manina in the episode 'In Theory'. This episode was the first ever to be directed by Patrick Stewart and I didn't realize this until after the track was finished. I sourced the Ben Nye makeup that was used to turn Spiner into Data, and a replica of the iconic Star Fleet uniform. Unfortunately I couldn't get the contact lenses in and I could only get the uniform in red, so I spent a huge amount of time changing the colour of my eyes and uniform in post. The video was shot in Slog 4k ProRes HQ using a Sony A7SII and an Atomos Ninja Flame. Lights included 3x Arri 800w Tungstens, 2x Socanland LED banks to light the screen, and one 2000w Blonde to simulate sunlight. BIG thanks to the guys at HD Rentals in Perth for helping me out. Thanks to everybody for their amazing support!
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Tuesday, 11 October 2016

The Art of Making a Nixie Tube

The nixie tube is a vintage display device which had been used until 70s when it was replaced with LED displays. The complex knowledge of manufacture of nixie tubes literally died with tube factory's engineers, glassblowers and machine operators. I discovered nixie tubes in 2011 and since then, I've devoted all my time to studies of nixie tubes and its manufacturing processes. After years of intensive work, with help of many people, I eventually succeeded and have revived the knowledge and equipment for production of nixie tubes. Dalibor Farny Subscribe: Read more on: Our website: Facebook page: Thank you for attention!
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Saturday, 17 September 2016

Modern day explorer?

In a recent podcast, Brady Haran of the fantastic 'Hello Internet', described an 'Explorer' as someone who, "travelled to a place, with no external help, and with little idea about what would be there when they arrived". This reminded me of the scariest thing that ever happened to me.

In the summer of 2001, I found myself in a really flexible job, and a great pal of mine had somehow gained access to a luxury speedboat. We took to taking trips down to Southampton on still and bright days, and spent them: on the water, roaming the streets of Cowes and exploring the coastline. One particularly hot day while anchored just off the Isle of Wight, we decided to take a swim in the sea. There was a buoy on the horizon which seamed to be a good target. After an idle swim for maybe half-an-hour we realise the buoy was not getting any bigger. My buddy was a better swimmer than me, but neither of us could be described as anything other than mediocre. After another ten minuets or more of focused swimming, we realise that it's just not getting any bigger at all, and decide to turn back.
It's at this point, with horror, we discover our great mistake. For the past forty minuets we'd been swimming, what turned out to be, out to sea - with the tide! We could no longer see the boat, but more worryingly than that, we couldn't even see the island or mainland. We were lost, lost at sea!

What could we do but pick a direction and start a swim back? Swimming towards nothing, with no real sense of direction, I can quite honestly say was the scariest moment of my life. It wasn't long, swimming against the tide, before I started to tire and my buddy had to keep hanging back, else we'd get separated. After a frantic swim for what seamed like way more than 3/4 hour, with no sight of land, I'm sure we stopped to discuss options, but don't ask me what we talked about, or even decided for that matter. Pressing on and after who knows how long, we finally caught sight of the island. Shortly after, I was more relieved than you know to find the boat.

Exhausted, freezing cold (for a hot sunny day), and hungry, I remember being so happy to just lay still on the foredeck of the boat. After recovering we drove towards the buoy. It turned out to in fact be an oil rig moored off shore. (The time comes to mind when Father Ted tried to explain the difference between 'small' and 'far away' to Dougal.)

So, does this count as being a true adventurer, or just a tad foolish? Perhaps it's both?

Tuesday, 23 August 2016

First Project On The Waxwing Spartan 6 FPGA Dev Board

This is a story about doing the obvious things first, and in the process defining a 'golden rule' of debugging hardware.

With the tool chain sorted out I'm clear to start designing configurations for my new Waxwing Spartan 6 FPGA development board. I think that it may be a good idea to start with something simple, and possibly useful, before jumping into some of the more complex peripherals. So first up is the on-board LCD. This way, in later projects, we can give ourselves a fighting chance at debugging our designs, when things don't go to plan.

The on-board LCD is a standard 16x2 HD44780 setup, in a 4 bit configuration, which has a pretty simple protocol. The only slight concern of this is the 4 bit interface, where we have to write the high nibble first, followed by the lower nibble. 

With almost zero thought I decide to use one of the off-the-shelf 'cores' that will bit-bang the initialisation and display data for us. I'm a big believer of reusing code, and seriously what's the point in writing this when there is almost zero scope to change what other people have done before. So, a tiny amount of searching leads me to stachelsau's LCD controller core, a nicely isolated routine that will take a simple signal containing the data we want to display, and just do everything for us. 

'Trying is the first step towards failure'
An update of the clock period and the constraints file to direct signals to the on-baord LCD, and everything feels like childs play. Synthesising the design and programming the FPGA and ...... ohhhh ..... nothing,  a blank LCD. 

OK, this is no problem, obviously I've:
  1. Specified the wrong output or clock constraints; no, they look fine.
  2. Is the LCD contrast turned all the way down; no, tweaking it makes no difference.
  3. Does the unit have power; yup, the LCD backlight is working fine.
  4. Is the configuration actually running (did I program correctly); a quick update to also flash a LED on the board works as expected.
So, not so simple after all. My list of 'traps for young-players' exhausted, it's time to break out some more serious assumptions, and test them.
  1. Maybe the LCD is duff
  2. Maybe the FPGA pins or traces (that lead to the LCD) are busted
  3. Maybe the design and/or core is not doing what I expected it to.
So, to discount #1, the on-board LCD is broken, we can re-direct the LCD control pins out to external headers and plug in an off-board LCD module. A few mins later and a nest of wires on the bench I have a similarly non working LCD. checking the possible problems we see that 1 and 2 have been (most likely) discounted. So sigh, its probably something to do with the core or design. 

This really is the fun bit, but is slightly earlier than I was expecting. So, what can we do here? Well, some people like to use simulation (I'd prefer to leave that to the testing, rather than use it as a debugging tool). Some people use a series of flashing LEDs. I find that works well when you have a slow and isolated area that you want feedback on, but not so great for seeing what's happening at a system level. I think what we need hear is a logic analyser. With a growing nest of wires on the bench, things take an awkward turn. The waveforms look exactly how I would expect!

Well, this could mean only one thing - that the LCD on the board is bust and I've not connected power to the off board LCD correctly. I break out the multimeter and check the break-out 5v power pins.... 3.5v! What? A check of the main board 5v rail also shows 3.5v. It's 3.5v everywhere. The board is powered by USB which I'm sure is 5v so, what gives. Tracing things round it looks like the guys at Numato directed both the USB power in, and the 7-15v power jack in, into the same 5v regulator, meaning that if you power the board using USB, the 5v will always be low because of the regulator drop-out. What the ****?

With the 5v line being low, it was enough to power the FPGA and LCD backlight, but not enough for the LCD controller. Switching over to power the board from an external 9v supply and..... presto, everything works as I'd expect.

And, here we have our golden rule : To quote a great man, Dave Jones of the EEVBlog, "When debugging hardware, thou shalt always check voltages".

The astute of you will notice that I had and passed right by the solution very early on. Point 3 of the original checklist "Does the unit have power; yup, the LCD backlight is working fine.". Note to self, a LED on does not mean we have the right voltage. D'oh!

Sunday, 31 July 2016