And the NodeBots from London assembled

I attended today’s NodeBots London event. The theme (?) was “NodeBots of London… Assemble!” and so we did. Compared to the last event I went to in July, which was way more informal, this was considerably bigger (within the venue allowances, of course) with more people and more things to look at and talk about!

First Oli made an introduction to NodeBots (essentially a place where people program hardware using JavaScript, but everything is allowed if you want to), what Johnny Five is and its relationship to node-serial, same for Firmata, and then some interesting tips for software people turned amateur hardware people I hadn’t heard of before, such as:

the case of the generous motor, in which you can fry Arduinos connected to motors without diodes, when the motor keeps spinning even after you stop applying input voltage, and so it becomes a dynamo which feeds current back into the circuit and so… bye bye Arduino which didn’t have any protection
the flappy servo, when you sequence value changes too fast and that results in just some feeble erratic movements instead of the dramatic ones you expected

Then Alex made an introduction to electricity, in general, which was a good refresher for people like me who studied some electrical engineering at uni/school but haven’t used it for reals since then. He explained the basics (V = IxR) and also insisted again on the importance of putting the right resistors in the right place to prevent things getting fried. He used this online circuit.js utility to depict circuits and the flow of current, the voltages at each point of the circuit (in the subcircuits perhaps?)–super useful and I so wish I had had this when I was taking these subjects. Makes things way more intuitive!

And with that—we hacked a bit! Jerome Loï (who had travelled all the way from Paris!) tried to resuscitate my pseudo fried Duemilanove with a shield and a thingy to mount the ATMega168 only, but turns out that it’s such an old board/chip combination that the bootloader firmware is not distributed anymore! So I left it aside and focused on my next task for the day: find out what the components in the kits I have are! With Jerome’s and Alex’s help, and some image searching, all the components were identified in a matter of minutes. Yay!

Then I was not sure of what I wanted to do—I didn’t really want to start a new project although I have a practical idea, and I was also hungry and Oli’s marvelous cooking skills didn’t help to stop making my stomach rumble. Whenever I tried to focus on hardware or research for my idea, a new wave of delicious slow-cooked stew would reach my nose. Ahhh!

Fortunately Charles made a lightning talk describing how he goes from thought to execution using a sketchbook and Autocad instead of thinking by executing as it’s advised in many environments (something like “you don’t want to waste time and effort on build something expensive that might not work, it’s better to think on a sketchbook first”).

Also someone (whose name totally escaped me, ahh, sorry) gave a little intro about a somewhat related event about which I heard about aeons ago but which seemed to have faded out, Dorkbot. It’s been revived, but I’m sad it is held in a) a quite remote location b) at a time I can’t go, because it sounds like the kind of thing I’d like to attend. SAD FACE.

And then it was finally time for lunch. As expected by the opening flavour, it was so yummy! It gave the day a sort of lovely family reunion for Sunday lunch, except we didn’t argue about silly things, but just used the time to catch up on what we had been up to since the last time I visited their maker space, or talk about what we were building today.

After lunch, I spoke to various people such as Andrew Nesbitt of manythings-fame, and learnt new cool things. Such as:

  • Platform.io which is an IDE for “things”, built on Electron… which can work with Arduino and also has code completion! so if you don’t like the Arduino IDE you can use this instead
  • The Arduino board clones such as the Funduino are interesting not only because they might be cheaper than the originals, but also because sometimes they offer cool features such as additional pins for +5 or +GND, which sometimes can make it easier to build something by connecting the wires directly to the board instead of using a breadboard to ‘multiply’ the pins. Or has a toggle to switch between 3.3 and 5V, etc. This very interesting tip came from Jerome, who also told me about this French shop called HackSpark which not only have a lot of those Arduino compatible boards on stock, but also might seem convenient for folks in the UK. And also have a physical shop in Paris! Wow!
  • The Espruino is small. Like… really small! It also transpiles JavaScript to Lua (if I understood this correctly). You write JavaScript instead of Arduino C flavour, and you can get really quick feedback. Sounds like a cool idea for prototyping without having to tether as with Johnny Five—most useful for wearables!

But my super favourite thing I learnt about today is that pencil lead is a conductor! Jerome built a quick and fun pencil based resistor which controlled the speed of a 555 timer connected to a speaker. So effectively he was changing the frequency of an oscillator, and changed the pitch of the sound as he moved the pencil tip closer or further away from the banana connector clipped to the paper. The other end of the pencil had a drawing pin inserted on it and a wire too, effectively closing the circuit! You can see all this in action in this little vine:

We also talked about how I should use an accelerometer and not tilt sensors for my idea (to avoid false positives), and ways to use Web Audio with hardware stuff, and ways to make things that made noise, even how to make a leslie / hammond! So many things that we can make! So exciting!

And there were many other things I learnt but I can’t recall now (hopefully my brain will retain them). Do join one of these NodeBots groups if you can—great things to learn and a very welcoming environment!

It was also cool to devirtualize people I apparently had met already but totally didn’t remember (hi Jerome… sorry), and meet new people! Hopefully next time I will remember 😀

Oh and Jerome, who was one of the main instigators of the NodeBots cat mesmerizer workshop at LXJS 2014, happened to still have a workshop kit in his travelling suitcase and gave it to me… which means I have a laser in my possession!

PEW PEW PEW LASERSSSSS!!!!!!

An e-mail from “Larry Page” (or my favourite spam in a while)

I got this spam e-mail, with sender “Google Inc ®”

Dear Google User,

You have been selected as a winner for using Google services. Find attached email with more details.

Congratulations,

Larry Page
CEO of Google

©2016 Google Incorporation ®

How exciting! I win for using Google services! Larry told me so!

Note also the “Incorporation” bit—totally cracked me up!

And there’s an attachment titled “Official Payment Letter by Google.pdf”.

Evidently it all feels very official 😏

A peek at Peer to Peer

It’s incredible how time flies and how changing the weather can be! Today’s a sweet bright slightly chill Monday in London, whereas last week it was VERY COLD and horrible.

I also happened to spend most of Monday in a studio in Islington recording my Peer to Peer session on… guess what… Web Audio!

The host was Drew Neil, from Vimcasts fame. He set a challenge for me that consisted in writing a system that could perform an interpretation of Steve Reich’s “Clapping Music“.

It’s a simple concept, but it also involves a lot of different techniques and APIs so it was quite a lot of fun!

Sadly you’ll have to wait at least a couple of months until the editing and subtitling is done. Until then… maybe you want to check out the existing videos!

UPDATE, about 15 minutes later: it’s grey and raining now. 👌🏼😂

From very annoying thing to slightly less annoying thing (and serial, and temperature sensors, and…)

You might recall the annoying thing I built with the Duemilanove before I left it in an unusable state. It was essentially the usual blinking example but with a buzzer connected instead of an LED.

But that wasn’t very musical. So I investigated a bit further. First I connected this huge chunky potentiometer to the board and learnt how to read its values. My idea was to change the voltage of what we wrote to the pin, depending on what the potentiometer said. A cheap way to experiment with how would different values sound in the buzzer, without having to recompile each time—interactive inputs are always so much better!

Analog reads give values in a 0..1023 range, and analog writes can only be in the 0..255 range. So to scale it I divided it by 4.


Continue reading From very annoying thing to slightly less annoying thing (and serial, and temperature sensors, and…)

No more tap tap tap sounds: yay!

A few days ago the fantastic Fritz from the Netherlands told me that my Hands On Web Audio slides had stopping working and there was no sound coming out from them in Firefox.

Which is pretty disappointing for a slide deck that is built to teach you about Web Audio!

I noticed that the issue was only on the introductory slide which uses a modified version of Stuart Memo’s fantastic THX sound recreation-the rest of slides did play sound.

I built an isolated test case (source) that used a parameter-capable version of the THX sound code, just in case the issue depended on the number of oscillators, and submitted this funnily titled bug to the Web Audio component: Entirely Web Audio generated sound cuts out after a little while, or emits random tap tap tap sounds then silence.

I can happily confirm that the bug has been fixed in Nightly and the fix will hopefully be “uplifted” to DevEdition very soon, as it was due to a regression.

Paul Adenot (who works in Web Audio and is a Web Audio spec editor, amongst a couple tons of other cool things) was really excited about the bug, saying it was very edge-casey! Yay! And he also explained what did actually happen in lay terms: “you’d have to have a frequency that goes down very very slowly so that the FFT code could not keep up”, which is what the THX sound is doing with the filter frequency automation.

I want to thank both Fritz for spotting this out and letting me know and also Stuart for sharing his THX code. It’s amazing what happens when you put stuff on the net and lots of different people use it in different ways and configurations. Together we make everything more robust :-)

Of course also sending thanks to Paul and Ben for identifying and fixing the issue so fast! It’s not been even a week! Woohoo!

Well done everyone! 👏🏼