Building Beautiful Things, RC2014 Mini II Picasso Ltd Edition

 

As a prelude to this post, I've stopped working, after a long time, for Tindie. No big story and you should definitely still browse and buy there. Other work and other commitments have taken priority and something had to give. I mention this as the kit in this post is an RC2014 product, if you don't know they make a range of retro computing Z80 kits. Not only that they have also spawned a load of add ons by all manner of makers. I know Spencer at RC2014 and so whenever I wrote up either a RC2014 product, or a product linked to RC2014 I had to declare an interest to my Tindie editor! So writing this post will feel unencumbered!

So yep, it's a GORGEOUS kit. These Mini II Picasso are a limited edition run and each individual kit will indeed be individual with no 2 having the same combination of PCB colour, silkscreen, LED colour, header colours etc. The kit is electronically the same as  Mini II but obviously the layout and design is spectacular. It's really nicely designed, oh, and it isn't rectangular! It's kind of shaped like a pint glass but it's hard to photo as it just looks like weird perspective. In case you don't know once built this kit can be run in a few different ways. The easiest is to grab an FTDI USB cable, hook it up and connect to this using a serial monitor, putty/minicom etc. Then, with some judicial placing of headers, you can boot into numerous environments, Microsoft Basic, CPM, CamelForth and more!

Back to the build though. The peculiarity doesn't stop at the weird shaped board and colours. There's some interesting techniques in this fun kit, some I have never done before like the sunken chip which uses a weird underside surface mount approach that is pure Picasso! Everything is a jaunty angle and yes those radial resistor arrays do have a shared hole! It really is fun, and actually no more complex than any other kit. It's supplied with a lovely lasercut set of upper and lower panels and indeed the upper panel has two choices one with access to the header sockets. I think it would be a slight challenge as a first soldering attempt, but as a second or third kit for someone it's very doable, with great instructions and there's a superb community of users online. If you fancy joining in go have a peruse of https://z80kits.com/shop/rc2014-mini-ii-picasso/

Super affordable, £9.60, Meshtastic, Xiao ESP32 s3 with Wio SX1262

 

I'm currently writing a fair bit about Meshtastic the awesome opensource off grid communications mesh networking project. I'm writing some upcoming articles on using the Raspberry Pi Pico to create a solar charged node to use as a repeater etc, but today I've been playing with currently the cheapest way to set up a Meshtastic device. 

The Seeed studio XIAO ESP32S3 & Wio-SX1262 kit contains 2 tiny (like thumbnail sized) PCB. The XAIO ESP32S3 board has USBC and and IPEX connector for connecting and (included) little WiFi and Bluetooth antenna. All of this comes in a pack for £9.60 in the UK. I ordered mine with excellent service from PiHut. There's the usual pins but also there is a tiny surface mount connector. The Wio SX1262 is a LoRa add on board and you can (but don't do it before you flash Meshtastic to the ESP32) simply click it onto the surface mount connector to create a little backpack add on for the XIAO ESP32S3 board. The Wio has another tiny Ipex connector for the included LoRa antenna. Whilst you might want to upgrade this antenna down the line, it's certainly enough to get you up and running, oh and there is battery charging on board to make this a super tiny portable unit. 

The device is supported with the Meshtastic Web Flasher tool and so it's simply a case of connecting the XIAO ESP32S3 whilst holding the (tiny!) boot button to connect it in DFU mode via a USB C cable. Once flashed you can then unplug the device and connect the two boards together. Reconnecting some power via the USBC cable, you should have a Meshtastic node all ready for configuration via either the Web Client via Bluetooth, https or serial connection, or connect up to it using the Meshtastic app on your phone. Oh and for Bluetooth... the default pairing code is 123456!

EDC Bag DIY Sewing Project

I've had this idea floating around for ages. Influenced by a few interesting designs I'd seen I wanted to make a small bag for every day carry (EDC). I mainly carry a wallet, a phone, glasses, a penknife/multitool and commonly a pen drive, yet I can often place these items in a vast variety of forgettable places! A small bag/pouch could accommodate them all. So that's the starting point of the design and quite early on I decided it needed to be small enough so that it can be used as a bag in it's own right, or as a pouch that can be chucked into a larger bag or backpack. 

Whilst I was away in FOSDEM I saw someone walk buy with an unfamiliar small Patagonia branded bag across their chest. What caught my eye was the unusual strap that also has small section of cordage at the ends. On returning I had a search around online and came across the above image. Interestingly I think that this bag is a knock off fake design that is emulating a real Patagonia "stealth" bag from a fly fishing range. It is similar but these offered on various marketplace sites for £11/12 are deffo not legit. That said I liked the general layout and the function of the bag. The other influence was I'd seen in a local outdoor equipment shop, the OMM Trio Map Pouch, which was a more complex folding design, but I loved the idea that a bag/pouch could be attached onto an existing backpack as a chest pod. 

So, to the sewing machine! This was my first attempt at a lined bag where I made the inner and outer in such a way that when finished all the seam were inside of the bag between the layers. I'd previously made some small pouches and used this cut to length style zip, but mounted the zip in the face/front of the design. Using this style of zip for a top zip actually didn't work too well and it would be better next time using a "closed end zip" which is manufactured to a specific length and has a spare couple of cm of cloth at either end of the zip so you don't need to stitch over the zip at all. That said all this means is that this attempt has slightly less neat zip ends but it's still functional.  

Working out the order of operations to assemble what I had in my head was quite a challenge. The front outer panel received some webbing loops (actually it's some nylon tough webbing in black with an overlay of decorative rainbow cotton webbing because why not!) and also received the patch pocket which was stitched on but the bottom seam left un-sewn, to be stitched when the full assembly took place.  

I definitely wanted to have 4 attachment points on the rear of the pouch so that I could attempt to use it as a pouch, as a bag with a traditional strap, and attached using the 4 points to a rucksack as a chest pod. Sewing these welded D rings into position was hard as, despite using a zipper foot on the sewing machine, its hard to stitch the webbing down when the D ring is inserted as it tends to clash with the sewing foot. 

Turing the bag all the right way around and seeing all the seams disappear is a very pleasant moment. There's always stuff I can do better, but for a first attempt at a nylon lined bag I was pretty pleased. 

It's nice to then make some add on's for the bag. Above is a para-cord box knot key ring I tied and use as an easy grab fob for the zip. It's a really nice little add on and also when the zip is closed I can push the fob through the last of the webbing loops pretty securely (see the last/bottom image). This means that it's unlikely that the zip can accidentally undo.

Another small sett of add on's is these tied elastic loops onto which I have tied a "ranger bead" knot using Paracord. The interesting thing about the ranger bead is it acts like one of those plastic cinch toggles and can slide up and down the elastic loop. This means it can be used with the bottom d ring attachment points as a "larks head" style of attaching the pod to a rucksack as a chest rig, as in the photo below. 

Finishing it off with a vinyl cut dog logo I'm really pleased with this item made out of leftover bits and bobs. I may well make a second iteration with a better zip and using some chosen fabric rather than this camo cloth I use for everything as I have loads! I could also see myself designing and 3D printing some smaller attachment components for the handle/strap and perhaps for the chest pod attachments. I know it isn't high fashion, I'm old enough to not care. Making Your Own Gear (#MYOG) feels punk as fuck and I love having items on my that I've made and that work well for my kit and my (hapless) brain! 

Charcoal Making (going to do some metal casting in 2025).

 In a slightly random last post of 2024 I'm going to quickly step through how to make small batches of charcoal! It's pretty well documented online but when I posted over on mastodon I got some questions asking about the process. 

As a random aside, why would you want to make your own charcoal? Well it's quite hard to get decent charcoal these days, most of the BBQ "briquettes" contain a lot of sand and fillers and the lump wood charcoal often commercially available is not to great and potentially not the most sustainably created. So for small batches of charcoal for firing up my small DIY furnace this approach works for me. 

We have some willow in the garden I regularly coppice and this makes excellent charcoal when dried out for a year or so. Begin by finding a tin can, I used a paint can but I've also used large biscuit tins before now, the geometry doesn't matter, just needs to be metal and have a lid that can be sealed on. Whatever your tin cut your wood up into pieces that will pack into the tin. You want to fill the tin as well as possible to reduce the amount of air in the tin and also just to maximise your yield as the volume will shrink as you turn it into charcoal. 

In the lid of your tin you need to make a small hole, or a pair of small holes, don't overthink this, if I had had a large nail I would have made one circa 6mm diameter hole, but I picked up my hand drill and it had a small bit in it and so I drilled 2 smaller holes close together. With your hole in place put the lid on the tin. 

Chuck your tin on a fire and keep the fire burning for a few hours, watching the tin you should see a stream of white gas/smoke coming out from the hole which may or may not catch fire and roar like a quiet jet engine! Once the smoke/gas stops you need to remove your hot tin from the fire and then cover up, or plug the holes to try and stop air from rushing into the tin. I've sometimes stuck the nail I've used to make the hole back in but this time I just used a flat piece of slate to cover it. 

Once cooled, open up your tin and you should be rewarded with nice lumps of charcoal that should be light and brittle. Even with a small paint tin if you repeat this process a few times you can pretty quickly build up a good store of decent quality charcoal. 

Repairing the Mundane, Bike Pedals!

 

If you follow me over on mastodon you might have got wind of one of my current ongoing projects, the restoration of a cheap but excellent recumbent racing bike. I'm collecting video and images of the process so I imagine there'll be a YouTube video and some posts at some point. I do lots of bike tinkering and it's really easy to fall into the trap of just adding better parts rather than restoring parts you have. I'm totally guilty of this but I do try and reuse parts elsewhere if possible. 

The recumbent arrived with a set of flat pedals on it. Painted bright red they were totally serviceable (one needed a little tweak of a nut to take out a tiny bit of play) but the paint was in poor condition. They are absolutely nothing special, they are alloy with cast in pins (the sticky up grippy bits) and as such would have originally been a fairly cheap pair of pedals, not even any branding or name. 

As I kind of progress as a maker type person I start to see more and more how much effort and energy goes into creating these low spec, but not the worst parts in all manner of products and items. If you have ever tried casting metal or machining some kind of curved bearing race cup you'll know too. 

Increasingly I see people repairing and I love it. I also see media starting to promote and push the repair agenda and I love that even more. However I've also noticed that, particularly in the higher end TV/documentary style repair stuff, that increasingly the things that are repaired are either very expensive high quality items (antiques etc) and/or things that people have incredible emotional attachment and investment in. Think Repair Shop and people weeping (quite rightly) over a wartime memento lovingly restored. 

I love it, but it's dangerous, it leads me back to these pedals, they are mundane. We need to repair the mundane too. It's highly likely that I will invest a lot of time into the recumbent bike project, and it might end up warranting technically better pedals than these. I might want different technology, I might want to clip in, but these pedals are serviceable and need to be reused. 

So I stripped them down, I sanded off the remaining paint and oxidisation and then gave them a coat of primer. I then realised that, due to their quick and budget production methods, they still had lots of casting flash from when they were originally made. Not warranting endless effort I ground back the worst bits and re primed them. I then did a poor but functional rattle can respray in a neon yellow. 

As part of the strip down I had to prise out the pedal caps to get to the retaining nuts etc. Of course these plastic items were very snug and to remove them created some damage. A quick measure with the calipers and a little bit of FreeCAD design work and I printed a pair of replacement caps in a pleasing green TPU filament. 

The axles were stripped and then re-greased before reassembly, they aren't pretty, I don't have a shot blasting cabinet or an indoor space for respraying so they are a bit rustic in finish, but, they are once again serviceable and, whilst I say the recumbent might warrant technically better pedals, these will find their way onto a project at some point rather than hitting landfill.

Inkscape Path Effect: Ruler

As a maker I’ve often ended up making rulers and scaled items. If you have access to some kind of laser cutter/CNC router or even just a regular document printer, you can create all manner of measuring and metrology tools! Inkscape can make this process incredibly straightforward with it’s Ruler path effect.

It is a pretty straightforward path effect. In a new project click the Pen tool then hold the control key and left click on the canvas and drag to create a horizontal line. Set the stroke width to something reasonably thin like 0.2mm and set the length of the line to something easily divisible. We opted for 100mm.

With the line selected click “Path – Path Effects” to open the Path Effects dialogue tab on the right hand side. In the path effects drop down menu search for “Ruler” and then select it to open the ruler dialogue. This will apply the ruler effect to our line and you will see some ruler markings appear spread along the line. They probably aren’t spaced correctly so we will edit the ruler dialogue variables to create the effect we want. Let’s aim for a mark every 1mm with a longer major mark every 10 marks so we get a 10cm ruler with mm and cm marked.

First change the “Unit:” drop down selection to mm then set the “Mark distance:” value to 1. You should now see that the ruler markings change to be equally spread at 1mm distances along our original line. Next you can set your “Major length:” and “Minor length:” variable so that you have longer and shorter ruler lines, finally set the “Major steps:” value to 10. You should now see your longer “Major length” lines now appear every 10mm marking every centimetre.

Of course, you aren’t limited to creating rulers that are marked every mm. You can use this versatile path effect to make all manner of scales and rules. In the header image you can see it’s been used to make some “roamer” tools which are used in map reading and navigation. The ruler path effect has been used to make marks where every 4mm represents 100 meters for the 1:25000 scale roamer which is a common hill walkers map scale. Note that the actual ruler marks in the corners of the roamer designs have been edited so they don’t cross over each other. This has been achieved by selecting the entire path effect ruler and clicking “Path – Object to path” this means that then every mark of the ruler can be edited using the “Node Tool” furthering the use of this great path effect!

DIY Opensource Land Navigation Tools.

I’ve been practising my land navigating a little bit recently. With the short days and winter weather it’s useful to practice walking on bearings and other navigation techniques for when visibility suddenly worsens! As part of this I've made some DIY navigation aids. First up is some DIY lasercut perspex roamers. This was partly as I wanted to write an upcoming tutorial on the Inkscape Ruler Path effect (See recent other posts on the offset path effect and the corners path effect) which allows you to create precise graduated ruled scales perfect for all kind of measuring tools.

A “roamer”, or “romer” as some people spell it, is a tool that’s particularly useful when it comes to defining a grid reference on a map. The premise is pretty straight forward you identify the first two numbers of the grid reference directly from the line labels on your map and you then place the zero corner of the roamer on the position you want to create a grid reference for and then read where the roamer scale crosses the map lines to the left of and below the zero point. As an example in the image the grid reference of the Pumping Station marked on the map could be given as SH605641 or even more accurately estimated as SH60556413.

Many compasses have roamers marked on them for common map scales but this project started as my older Silva compass I’ve had for years didn’t have a roamer for 1:40000 scale which is the standard map scale for Harvey maps. After drawing the scales in Inkscape I then added a couple of scaled holes in the roamers which are handy for defining a circular area of a known radius on a map.

I’ve posted the roamer designs as they stand here and they are perfect for laser cutting and engraving, but equally, you could print them on card and they would work just as well!

Secondly I’ve been making some “ranger beads” from Paracord which is an interesting pretty knot with which you can create a sliding bead. A great use for these is they can replace a cinch toggle which is handy but you can also use them to make a great set of pace beads for navigation. There are many tutorials for this knot online like this video on Youtube.

The premise of pace beads is to keep track of the distance travelled on foot and it’s super handy if you suddenly end up walking on a compass bearing with no visibility. I’ve tied 10 ranger beads onto a doubled length of Paracord and then I can slide one bead to the opposite end of the cord when I have travelled 100 meters. To identify the 100 meters you need to somehow mark out 100 meters on a flat surface and then walk the distance counting your paces. It’s common to count 2 steps as a pace so for example you count every time your left foot lands. A good place to find 100 meters marked out is an athletics track on a local sports field, but failing that you can use online maps to drop a pin at a location and then measure out from the pin 100 meters and note exactly where that is. I’m quite tall so my average paces for 100 meters is 58 paces. I loop the pacer beads onto my rucksack strap and then as each 58 paces passes I pull a bead to the bottom, resetting all the beads when I have done this 10 times (Note I could really have just tied 9 beads as the resetting could be the tenth!). 

It’s really accurate, with practice you can even adjust your pace number for when you travel uphill or downhill and I find that I can, checking with the Ordnance Survey map route plotting and other GPS mapping) I can keep to within 50 meters accuracy over 2km, way more than you would travel without checking on a bearing.