Tiny DIY Knife from Hacksaw Blade

A lifetime ago I was really into Locksport and in particular into making manual tools and picks, I'd often use hacksaw blades as a cheap stock of very hard decent steel. I've also always wanted to tinker with knife making and today the synapses all fired at once and I made this.

 

 Starting with a small length of hacksaw blade I made a crude drawing on some card, cut it out and glued it to the stock. Ages ago I bought one of those tiny, cheap, yet surprisingly useful 12V belt grinders. I could do with making some jigs/holding to make my bevels absolutely correct but for half an hour of off hand grinding it's not the worst for a first attempt.

 

I ground out the original hole to accomodate the little piece of brass tubing I'd found and I also ground a hole (this steel is incredibly hard to drill unless you temper it and re harden) and throughout the grinding I kept cooling the blade in water so it didn't lose it's hardness. 

 

Then a super quick little bit of design work in FreeCAD and some 3D printing it was time to assemble. The scales are printed in PETG and I've used some epoxy resin to hold it all together. Despite my grinding it's wicked sharp so I deffo need to come up with a small sheath. Finished off with a small lanyard it's been a good fun little project and it's possibly inspired me to look for a larger piece of steel for further attempts! 

 

SOURCE Issue 1 out now! Computational Fluid Dynamics

 I've been tinkering on two things a lot for the last couple of months. One has been an odyssey into learning Computational Fluid Dynamics using the amazing CfdOF FreeCAD add on workbench. The second is I've been wanting to, for a long time, learn some kind of opensource tool for page layout/design.

 In an effort to create a commitment to this learning I've decided to launch something called "SOURCE". SOURCE is a little home for me to place longer tutorial content that's beyond what my amazing paying clients would want. I'm aiming to bring one out every quarter (the observant will note issue one is marked as June 2025 so I've given myself and extra few weeks for Issue 2)!

 It's opensource, it's made in Scribus and the archive for this issue can be found on Github here under a CC-BY-NC v4.0 license. It's free... or it's pay what you feel! There are donation links in the PDF for Paypal or KoFi, it's a HUGE amount of work even for this first 11 page experimental issue so any donations will help me keep assigning hours to it. I plan to have larger and more varied content in upcoming issues. Finally... do share it! I'd love it to be decentralised and disseminated far and wide... send the PDF in email (compression may help), host it somewhere, seed it, whatever! Download SOURCE Issue 1 here.

Picocalc, Having fun with PicoMite!

 

So I am a sucker for portable tech. In fact as well as a heap of old Palm PDA's I own things like a Pocketchip and indeed every portable so far released by ClockworkPi. So the latest offering from them, Picocalc was always going to be on my desk too!

It's a fun platform and I think I can really see it getting some traction over the next few years as it's already been hacked around on a lot by the community and it's available for $75. AND, wonderfully, it arrived after a few weeks, much better than my pay now wait 18 months for my Uconsole! 

So what is it.. well, It's a Pico compatible handheld that ships with a Pico on board flashed with PicoMite which is essentially a port of MMBasic. Assembly is gorgeous with superb instructions and the build quality is high and typical of ClockworkPi products. It's got a nice screen and you can power it from one or two 18650 cells. 

The keyboard has a click but it's pretty nice to use and feels like a spacious thumb-board. You can do a stack on it and it doesn't get to wearing! Oh and the keyboard is back-lit with two brightness levels so it's pretty lovely to work on in low light. 

Over on the forum there is LOADS going on with this. There's already lots of different bits and bobs ported to it, Micropython, Lua, Lisp and more. And that's just with the onboard Pico. Tantalisingly (and I have one on my desk for when I get to it) it's possible to insert a Luckfox Lyra board which can run full Linux environments, there's a really active thread where this is being developed very quickly, loads of game emulators, people working on getting WiFi adaptors up and running and more. Amazing. 

For me in the week or so since I built mine I've just been tinkering with it in Basic mode, I'm mucking about relearning basic and slowly working on a little suite of calculator scripts for useful things for me (descent rate calculators, parachute design stuff etc). It's such a nice object to tinker on and feels cool to be working with older languages like Basic whilst having modern stuff like a vacuous SD card to save stuff too!

Lovely Friends make Lovely Things, Steam Engineers Spoonbot

I've met some lovely people in my time as a maker/tinkerer. None more so than the mighty Snoof and Chris who form Steam Engineers. They are constantly working on expanding STEAM activities and making inclusive exciting STEAM education available and accessible. So I was delighted when they sent me a new little item they had made, Spoonbot. 

Spoonbot has a few aspects, it can be a reasonably challenging soldering kit, features some microprocessor entinkerment so could be used for beginner and intermediate STEAM activities, which the team will happily talk to you about delivering. However, it can also be bought as a fully built object from their Tindie store and it's that I was gifted. 

The lovely full colour PCB has the robot design on it and it's flashed so that you have a small rotary dial on the side with which you can adjust your Spoonbot LED level. For those that perhaps run out of spoons socially and struggle to sometimes communicate that this is a really valuable tool to tell others in the world whether your social battery is full or somewhat depleted. 

I love it as a concept and if you know someone who'd appreciate it, go buy one, you're supporting lovely people doing brilliant work. Oh... and it's fully opensource and OSHWA certified. 

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!