Monday 29 September 2014

BarCampLondon X

So that was a pretty busy weekend! Thank you to all the organisers and the sponsors for yet another amazing BarCamp London.

If you don’t know what a BarCamp is, go read about how it works, and then come back to read my notes on some of the sessions I attended.

Here’s a picture of all the sessions that the attendees ran over the weekend (that’s a lot!) and it doesn’t list all the random conversations, games and general meeting people that happened outside of the posted schedule.


Dan Hardiker @dhardiker

  • one day workshop
  • aimed at age 8-16
    • 8-9 year olds treated a bit differently — they need a bit more guidance
  • with specific goals
    • make a robot
    • iOS game development
  • want to say “I made that”
  • one child been building iOS apps since age 6:
  • worldwide
  • dominican republic had > 1000 kids over 2 days
  • > 30% people who come are girls/women
  • generally 5 or 6 tracks selected from:
    • minecraft modding
    • scratch
    • python
    • lego mindstorms
    • raspberry pi
    • arduino
    • greenfoot
    • alice
    • kojo
    • iOS
    • mathbreakers
    • NAO robot
  • 4 sessions in a day
  • also go to big conferences and run devoxx4kids for the adults
  • first London event in June
    • got 95% attendance from people who signed up!!
    • 4 x 1hr sessions
    • 40 volunteers
    • had an 11 year-old fly over on his own (met his dad at airport) to run a group of 20 x 11-15 year-olds how to do minecraft modding
    • he also did a closing keynote
  • had the creator of greenfoot teaching how to build a minesweeper game
  • have a load of volunteers available to help children build stuff
  • have a show and tell at the end of the day
  • mindstorms:
    • build the main wheelbase
    • children add grab arms to grab a ball
    • get children to control by hand first
    • program the same steps (5 steps forward etc)
    • add touch & distance sensors
    • program to grab without hard-wiring distance

how to start a hackerspace

Matt Copperwaite @mattcopp

  • start a company - level of protection
    • limited company - need 3 people, can then state not for profit
    • community interest - lots of paperwork
  • business bank account
    • barclays have APIs, £50 cashback at the time…
  • insurance: paid £300/year
    • recommendation from London Hackspace
    • BIS will issue advice on this shortly
  • keep trustees involved
    • raise issues that split them: colour of the logo…!
  • system designed so you can cancel the membership at any point
  • get people signed up with open days
  • people really like laser cutters!

See current UK Hackspaces at:

kinect v2

Mike Taulty @mtaulty

  • v2 is £159 (cheaper than v1 at £199!)
  • HD video
  • infrared
  • depth sensor
  • can track up to 6 bodies (25 skeletal joints)
  • tracks depth from 0.5m to about 8m
  • infrared & depth is much lower res: 512 x 424 pixels
  • body index separates pixels of different bodies
    • lets you do green screen really easily
  • MS’s SDK is Windows only (doesn’t work with Windows VMs since it needs USB 3 & DirectX 11)
  • but libfreenect2 is an alternative open source driver for Mac/Linux

mobile network in a field

Sam Machin @sammachin and Kevin Prince @kevinprince at EMF Camp 2014

  • EMF Camp was c.1200 people
  • runs every two years
  • “a very british burning man” or “glastonbury for nerds”
  • aiming for phone calls but not data
    • mainly because of there was already fast wifi
  • just three base stations, so could simply architecture a fair bit…
  • using OpenBTS, Asterisk + Twilio & Heroku
  • Asterisk server sat in the on-site hosting centre
    • a refrigerated shipping container with servers on pallets
  • recreated phone supply chain by using Amazon & a tent
    • bought some Amazon burner phones on 30 day return…
  • SIMs were the hardest things to sort
    • wanted to play nicely with other networks
    • didn’t want people on real networks to connect to camp network
    • SIMs are pretty expensive: 50p to £1 each
    • hard to order in low quantities
  • bought OpenBTS boxes from RangeNetworks
    • startup in SF
    • mostly selling to small Pacific islands
    • massively cheaper than normal kit (c.$5K)
    • also put one in a search & rescue helicopter in Iceland
    • connects to someone’s phone as it flies over
    • locates to area of a football field
    • allows helicopter to call phone!
  • need spectrum to run in the UK…
    • O2 had some they had forgotten about ;-)
    • concurrent spectrum license: shared by 15 companies
    • better in other countries:
      • Netherlands: just need landowner permission
      • Germany: just need 30 days notice
      • Burning Man: use DARPA military spectrum not in use in the middle of the Nevada desert
  • antennas make a big difference
    • need a proper site survey
  • EMF Camp provide about 40 routers around the site
    • set up in locked portaloos! Datenklos (term from CCC)
  • created everybody’s accounts ahead of time
    • needed to map phone numbers to IMSIs
    • got people to type in last 4 digits of SIM
  • set up voicemail using twilio to record and forward via email
  • SMSs are harder if you need to store & forward
  • dealt with inbound calls by having a single central public number
    • call it and then dial 5 digit account number
  • added outgoing calls as well (via Twilio)
    • limited to c.3 minutes
    • but even so fairly cheap
  • also set up a few group rooms to see if people used them
  • stats:
    • ~200 SIMs handed out
    • ~100 attached users at any time
    • close to 100% coverage
    • about 1800 minutes of twilio
  • ideas for next time:
    • phone boxes
    • POTS to tent: turn up and plug in a BT phone!

managing CSS

Ben Scott @BPScott

  • people keep on writing new CSS
  • not obvious how and where things are used
  • no confidence in what you can change and if it will break anything
  • build smaller isolated things
    • single responsibilities


  • components
    • domain-specific objects
    • text next to image in a particular way
  • macro layout
    • grid system
    • layout of components within a page
  • theming
    • colouring of components

resulting composition

  • this thing, here on the page, in this colour
  • mobile first & extend from core functionality
    • much easier to reason about adding in CSS
    • harder to take things out
  • use additional classes to toggle additional behaviour
  • Brad Frost: atomic design
    • pages are accidents — what happens when you put components in a particular order
  • create a styleguide page
    • component, layout variations
    • automatically generated from HTML partials in application
    • HTML partials are essentially custom tags


  • avoid using IDs in CSS selectors
  • try to keep selectors to max 3 levels
  • naming convention: BEM
    • double underscore = within
    • double hyphen = modifier

problems & breaking up

  • mobile first, but oldIE needs to be desktop first as it doesn’t understand media queries
  • could use respond.js but takes a lot longer to load
  • created Breakup
    • SASS/Compass plugin
    • generates different CSS files from the same SASS input
    • according to directives in top-level
    • lets you avoid wrapping specific elements in media queries

real life brain training


  • split activity into different frequency bands = EEG
  • delta < 4 KHz
    • babies have this all the time
  • theta 4 - 7 KHz
  • alpha 7 - 14 KHz
  • beta 15 - 30 KHz
    • focused
  • gamma 30 - 100 KHz
    • complex active stuff
  • other stuff:
    • Mu (8 - 12 KHz)
    • SMR (13 - 15 KHz)
  • neurofeedback
    • constant feedback, close to realtime (~200ms)
    • useful to use more than one sense to enable different people to relate to it better
  • current system has five measurement points
  • Chief Science Office is Leslie Sherlin


  • focus:
    • augment low beta
    • inhibit theta & alpha
  • can train stress response too
  • sports consistency
  • exam preparation


  • QA engineer was overusing focus training
  • had problems sleeping…

uses (not scientifically proven)

  • worked with Felix Baumgartner
  • tennis players
  • reported to alleviate long term ADHD…
  • improved sleep patterns amongst developers…

available systems

  • medical
    • existing $10K for bare minimum
    • require expensive software, only run on Windows XP
  • kickstarter systems
    • cool, but not much neuroscientist input
    • not so accurate or useful
  • versus
    • looks like headphones
    • rebaseline every time you put it on
    • connects over bluetooth to iPad
    • uses dry spikes sensors that contact scalp
    • first consumer product $750, aiming for $500

toys & gadgets

  • thalmic myo
    • bluetooth armband picking up arm and hand actions
  • oculus rift
  • NFC ring
    • lower range than usual
    • internal and external tags (private & public?)
  • Google Glass
  • estimote beacons
    • use at least three to get indoor location fixes
    • google have set up mountain view…
  • chromecast
    • don’t bother with a digital picture frame — just get a cheap TV and one of these
    • great for broadcasting any media around the house
  • almond+ touchscreen router & home security
  • 3D printer
    • check out 3d printer subreddit
    • solidoodle
    • arduino will be launching one v. soon
  • MIOPS camera trigger
    • plugs in to flash hotshoe
    • light sensor
    • laser sensor

scaling agile

Matt Walton, Head of Product @ FutureLearn @matt_walton


  • have documented a lot of their processes
  • think it, build it, ship it, tweak it
  • now about 2000 people
  • squads consist of engineers, designers & agile coaches
  • autonomous teams with long running missions
  • spotify engineering culture
  • “agile at scale requires trust at scale”


  • lots of information radiators
  • product roadmap split into team “swimlanes”
  • have a scrum of scrums


  • similar teams
  • each team needs:
    • product management
    • design lead
    • tech lead
  • how to organise a roadmap
    • KIPs broken into themes
    • time box themes
    • agree measurements
    • form autonomous team
  • lean analytics (book)
    • ratio or rate, not a total number
  • business focussed aims:
    • if … then … because
    • based on lean analytics experiments
  • two backlogs: separate “hygiene”
    • then add 70% valid features, 30% bugs, tech support to each iteration


  • product strategy themed by vision areas
  • each sprint split by % of work for BAU, products, etc
  • standups and retrospectives still whole team to encourage community
  • though work done in smaller project teams


  • share vision, mission & values
  • give autonomy and create community
  • rhythm & reflection

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