Gerrit Niezen

Over the years I've built up a collection of random electronic parts, from Arduinos to loose resistors. I've been storing them in various boxes, containers and a locker at the Swansea Hackspace, but I really can't remember what's in there anymore.

A while ago I came across a blog post on how to organise electronic parts using Partsbox.io, and since they have a free account for home users I've decided to give it a try.

I got hold of 100 small (2.25” x 3”) clear resealable bags on eBay[1], to be able to sort and label the smaller components. I wish I could justify buying a label printer[2] as they look super fun to play with, but for now I think I will just use a sharpie and blank address labels.

This is going to take some time, so I hope to give an update on my progress with a future blog post, in terms of how long it took and whether it was actually worth it.

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1. for £1.80 including P&P ↩︎

2. like the Brother QL-700 ↩︎

#Electronics

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A shower thought I had this morning was to see if there's an Arduino shield that could act as a USB host, also known as USB OTG (On-The-Go), that I can plug that into the Espruino Pixl.js.

Why would I want to do that? Well, that would allow me to read data from USB devices, like the insulin pumps and blood glucose meters I develop drivers for in the Tidepool Uploader, display some of the data on the Pixl.js display, and then forward it onto a smart phone or computer via BLE.

Turns out there are at least two Arduino USB host shields, the official Arduino USB host shield and one made by Sparkfun. If I understand correctly, the official one connects through the Arduino's ICSP header, which is not available on the Pixl.js, leaving me with the Sparkfun option.

Both use the MAX3421E USB peripheral/host controller chip, so I'm wondering if I could eventually design a little dongle that consists of the MDBT42Q BLE module inside the Pixl.js and the USB controller chip. The BLE module is £6 in volume, and the USB controller chip between £4.50 and £6.50 depending on quantity. This makes it more expensive than a Raspberry Pi Zero W, even before you add the PCB and discrete component costs, but it should be much less power hungry.

#Electronics

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Bluetooth Low Energy (LE), also known as Bluetooth 4 and formerly known as Bluetooth Smart, is supported by most mobile and desktop operating system and can be found in many wireless devices. It was developed by Nokia in the early 2000s and first marketed as Wibree, a competitor to the Zigbee low-power wireless standard.

While Zigbee is used in many smart home devices, like smart meters and light bulbs, the rebranding of Wibree as Bluetooth LE helped it to take over the smart phone market, with around 90% of new mobile devices now supporting Bluetooth LE.

Bluetooth LE has open specifications (called profiles) for various types of devices, including blood glucose meters (BGMs) and continuous glucose monitors (CGMs). At Tidepool we've had to work very hard to get communication specifications from device manufacturers in order to communicate with their devices over USB. These are all proprietary protocols which have to be developed for and supported separately, and apart from Ascensia (previously Bayer), not a single company have published their protocols in the open. Now with Bluetooth LE, having a common standard specifying how these devices should communicate that is supported by device manufacturers is great!

I downloaded an app from the App Store called nRF Toolbox by one of the Bluetooth LE chip manufacturers, Nordic Semiconductor. It has support for various BLE profiles, including the BGM and CGM profiles. I was able to successfully connect to and read data from a Bluetooth LE-enabled BGM called the True Metrix Air, after entering the device serial number to pair:

#Tidepool

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This morning I got a Pixl.js Espruino board for Father's Day. My son is not even two years old – how did he know that is exactly what I wanted?

The Pixl.js is a SoC (System-on-Chip) with a 64Mhz microcontroller and Bluetooth Low Energy module. It's an Espruino board, so you program it in JavaScript. It has a little LCD screen just like the ones in those old Nokia phones. Pixl.js's form factor is Arduino compatible, so you can plug in Arduino shields like WiFi or GSM. It can run on a coin cell battery or is powered via USB (power-only).

It works over Web Bluetooth, so you connect to it from the Espruino Web IDE. The only thing I had to do to get it working on Ubuntu 18.04 was to enable the “Experimental Web Platform Features” under chrome:flags on Chrome and then go to espruino.com/ide.

I then tried to get it working on my iPad. Unfortunately Web Bluetooth is not yet supported on Safari, but there is a WebBLE browser you can download from the app store (for £2) that does. It's a very basic browser, but all you really need it for is to run the Espruino Web IDE. That I can program a little microcontroller over Bluetooth from my iPad blows my mind!

#Electronics

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This morning I was watching Estefannie Explains it All on YouTube making a Daft Punk helmet using her new 3D printer.

She was 3D printing a mold and using that to vacuum form a visor out of a PETG plastic sheet. What I love about her videos is that she shows everything, including her failures, like completely melting the plastic sheet or gluing the box to her workbench by accident.

I've watched other makers on YouTube and usually feel inadequate when I look at their amazing skill set, even though I have a Masters degree in computer engineering and a PhD in industrial design. With Estefannie, it's refreshing to see how she's learning as she's making and sharing the whole process.

As she was making the vacuum forming box I noticed many things that could be improved, for example how she was clamping things to her workbench. Instead of pointing that out in the comment section (which I'm sure many people will do) it reminded me that I don't have to know how to do everything perfectly before starting, and that even if you make mistakes you can still make something awesome.

I used to think that looking at great maker projects will inspire me to make things. That's not true – looking at the process, including all the failures and mistakes, is what provides true inspiration.

#Making

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I first came across solarpunk on the decentralized social network Scuttlebutt[1]. Like steampunk, and later dieselpunk, solarpunk is a certain narrative and aesthetic about the future. The article “What is Solarpunk?” does a pretty good job at explaining what it is.

On Scuttlebutt I discovered a whole community interested in solarpunk, and someone mentioned that there was a Kickstarter project to translate a Brazilian anthology of solarpunk stories into English. I backed the project, and ended up with two collections of solarpunk short stories in e-book format:

• Solarpunk: Ecological and Fantastical Stories in a Sustainable World
• Glass and Gardens: Solarpunk Summers

I'm actually reading both of them at the same time. I've found “Glass and Gardens” a bit easier to read as it was originally written in English, with “Solarpunk” being quite awkward in places due to the translation from Portuguese. Hey, maybe I'll put a review up here once I finished reading them!

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1. You can access Scuttlebutt with a software client like Patchwork. For more on Scuttlebutt, see “An off-grid social network” ↩︎

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I enjoy listening to podcasts when I'm out on a run or walking to town. Overcast is my podcast player of choice, at least until Apple releases the next version of their Podcasts app that will let me store podcasts on my watch.

In no specific order, here are my favourite three podcasts at the moment:

• Do by Friday: Merlin Mann, Alex Cox and Max Temkin (the last two from Cards Against Humanity) have a weekly show where they discuss tech, politics and pop culture. And there's a weekly challenge.
• The Prepared: Spencer Wright and Zach Dunham created The Public Radio, a single-channel station FM radio in a jar. In this podcast they talk to designers and engineers about manufacturing.
• Thorougly Considered: Dan Provost and Tom Gerhardt are Studio Neat, creators of the Glif tripod mount for smartphones (amongst other things). They talk about product design, crowdfunding and indie manufacturing, with host Myke Hurley of Relay FM.

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There has been a noticeable trend from people reading blogs towards reading e-mail newsletters instead. I use Feedly to subscribe to blogs[1], but if you don't use a blog reader I guess e-mail makes more sense. Here are a few newsletters that make it into my inbox, even if I prefer blogs.

• Offscreen Dispatch is a once-a-week newsletter with an assortment of products and articles on design and the web by Kai Brach, maker of Offscreen magazine. Coincidentally Offscreen is also my favourite magazine at the moment.
• The Prepared is a manufacturing newsletter targeted at engineers and entrepreneurs by Spencer Wright, who also hosts The Prepared podcast.
• Sunday Dispatches is a little bit of everything by Paul Jarvis. He usually writes about freelancing and small businesses.

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1. Hint: You can subscribe to this blog by clicking the Subscribe link at the top of the page. ↩︎

#Reading

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I discovered a customizable design for a door stop on Thingiverse, where you can resize it to fit the door holes in your house. I measured the holes, modified and 3D-printed the design, and it turned out to work much better than expected.

I then needed a way to keep our wardrobe door closed. I couldn't find anything on Amazon or any existing designs on Thingiverse that would work. So I started creating some baby-proofing designs of my own.

I noticed that there is a small gap at the top of the wardrobe door, with a knob just behind it. So I thought “why not make something that clips to that knob that prevents the door from opening”? Ladies and gentlemen, I present to you the wardrobe door holder :

It should work with any IKEA PAX hinged wardrobe doors. I posted the wardrobe door holder on Thingiverse if you just want to download the STL file to print it yourself. Here is the OpenSCAD code to make or modify your own wardrobe door holder:

$fn=50;

difference () {
  cylinder(5, d=16);
  translate([0, 0, -1]) {
      cylinder(7, d=11.9);
  }
}

translate([-4,6,3]) {
  cube([51,10,2]);
  translate([0,0,-3])
      cube([7,10,3]);
  translate([41,0,-10])
      cube([10,10,10]);
}

I also made a simple hook that clips over two IKEA PAX door handles:

And here is the OpenSCAD code, which is easy enough to modify by changing the variables for width, thickness and height:

width = 82;
thickness = 5;
height = 25;

cube([width+thickness,thickness*2,thickness]);
cube([thickness,thickness*2,height]);

translate([width+thickness,0,0]) {
  cube([thickness,thickness*2,height]);
}

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I've been looking for a way to very easily write and publish posts. I've tried static page generators like Hugo and and Jekyll on GitHub Pages in the past, but there are just enough steps to create too much friction.

First you have to write your markdown files in a text editor. Then you have to compile it and publish it using a computer. I was looking for a quick way to write posts, even on my phone or iPad (with a Bluetooth keyboard). SimpleNote came close to what I needed, except that each post exists completely separate to other posts.

Enter Ghost. I spun up a Digital Ocean instance and followed the tutorial for setting up the one-click application. Easy peasy.

Now I am self-hosting my own content and I can type away on any device that can load Ghost's web-based Markdown editor. Adding header images is super easy thanks to built-in Unsplash integration, and then publishing a post is one click away.

In future I hope that decentralized solutions like Beaker browser and the Dat project will make it much easier to publish blogs in a decentralized fashion, but until then running my own Ghost instance seems to make the most sense.

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