Raspberry Pi Desktop For UMPC Repair!

I love UMPC, the idea of being able to carry a complete system in a pocket or small bag has always appealed and I've had a raft of machines, from my old  HP Jornada 720 through to a (sadly died) One Mix Yoga. One that I had never owned is a Sony Vaio P Series. When one came up on ebay with no HDD and a wonky network card I couldn't resist. 

This is a P11z and is widely regarded as a bit of an overpriced dud in it's day! The 2GB ram and the 1.3MHz single core processor left a lot to be desired especially when running WinBlow$ Vista (aaargh) off a 4200rpm HDD. However, running a lighter distro and an SSD I wondered if it could be a useful note taker. 

So a 1.8" Zif 40 pin SSD was ordered and fitted and the network card issues where solved by simply re-seating it and re connecting the antenna cables! After my explorations a while back getting Linux to run on  Linx 1010b I was expecting a battle and also having read a lot of people struggling with drivers I was considering my options. Then a brainwave, I wondered how well the Raspberry Pi desktop would work, a quick test with a live USB was stunning, everything works! 

Whilst it's still not the quickest machine in the world its actually super fun to have the RPI OS on a super portable machine, I installed the image with all the optional software and whilst primarily this machine tends to hang around with notes for a project open in Libreoffice Writer, its fun to play with Mu and Wolfram and other stuff included in the RPI Desktop. 

FreeCAD mini series in Hackspace Magazine. Issue 37.

 

I've just updated the blogpost where I keep track of all my articles for Hackspace magazine (Here if you are interested) and whilst I have the cover feature this month on Robots I wanted to just post about the other piece I have in this month. It's the first part of a mini series about learning the wonderful FreeCAD software and is aimed at both beginners in CAD and beginners in FreeCAD. 

I haven't written much about why FreeCAD as opposed to other, perhaps more well known, CAD platforms. For me part of it is that I love the opensource movement and agree with its ideals in all sorts of ways. That aside, FreeCAD also has a few other benefits. Whilst it's complex, that complexity is also astonishing in terms of what it brings. I've played with FreeCAD for a couple of years and I still feel quite like a newb when I see the amazing things people in the FreeCAD community can design. Later in the mini series we'll have little overview of add on workbenches and some of the more esoteric sets of tools FreeCAD has. From designing and analysing hand gliders to simulating boats to FEA/FEM and more. It really is a feature rich piece of software capable of designing anything. 

More practically I like that FreeCAD isn't cloud based, this means that I can carry it with me regardless of connectivity wherever I go. Important in none ubiquitous WiFi N Wales but also important after this week where lots of the internet globally has been hit by outages. Finally, I'm loving how FreeCAD, due to it's opensource status, fits in with other software. There are some really interesting things going on in terms of FreeCAD and KiCAD, and the fact that FreeCAD can handle OpenSCAD scripts directly is a bonus. There are also some nice workflows between Inkscape and FreeCAD. These are things that are hard to find with less free, more proprietary CAD packages. Love it! Check out issue 37 of Hackspace Magazine here. 

TS100 Cable Mod, Super Silicon

This little modification sits firmly in the "I should have done this months ago" file. I love my TS100 soldering iron and have blogged about it before. I normally power it from one of a couple of spare laptop power supplies that are kicking around and it's fine ...ish.. The laptop power supply cables aren't that flexible and this particular one had an angled plug which makes handling the TS100 a bit weird. 

When I bought my TS100 it came with an extra cable which is a really nice soft and flexible silicon cable with a barrel connector at one end and an XT60 connector at the other, this is a great cable that allows you to run the TS100 of a LiPo battery. It was only today that the synapse fired! Cutting off the barrel socket on the power supply and soldering an XT60 connector to it means that I can use the very nice silicon cable as the last bit of cable both at my desk and in the field. 

Pi 400 My Thoughts

I mean I'm already set up to invoice Raspberry pi as a freelancer so I don't know why they don't hire me to model all the new products.. :) Yes, I have a Pi400 and in case you have been under a rock it's the latest raspberry pi offering where they have shoehorned an adapted version of the PI4 4GB into a keyboard and made a complete computer package out of the box. 

I've had mine for a few days and had time to have a little play. I'm late to the game so there are lots of reviews and tear downs out there so this is just my little collection of thoughts and findings. 

First of all, I went for the Pi400 package only, not the option with a mouse and SD card as I have those in abundance, similarly so with a micro HDMI adaptors. For setup I've used the full Rasbian image with the optional software. 

Hardware wise it feels very nice in hand. It's pretty solid feeling and is very compact. Definitely suitable to chuck in a bag and carry about and I wonder if we'll see people incorporating it into cyber deck type builds. The keyboard is a nice size and the travel on the keys is pleasant and its pretty nice to type on. I LOVE that there is a power key on F10! It's great to be able to shutdown and then, whenever you want, press the raspberry key and long press F10 to boot! So pleasant after much plugging and unplugging of pi over the years. 

There's been a lot of discussion about the fact that raspberry pi kept the micro HDMI connectors similar to the ones on the Pi4. There are a fair few people who don't approve and wondered why in this build they didn't opt for full size ones. Essentially rpi design crew reckon that micro HDMI is the most future proof and will have the longest support. I am less concerned about the micro HDMI as I've found them pretty robust in use. The one thing I wish they had done is to space them out from each other. If you use the chunky none cable type micro HDMI to full size adaptor it's impossible to use two of these side by side in the micro HDMI sockets. So a little tip is to go for the cable style adaptors. 

In use, it's pretty capable. The slightly updated processor IC has been overclocked to 1.8 GHz but theres a heap of thermal gubbins inside so its totally cool and stable. It zips along quite readily and runs the usual games and programming stuff bundled in the raspbian image. I've also tinkered with inkscape and KiCAD on it and it handles these really well. Similarly web browsing and video streaming all works fine. For general office, light browsing and stuff there is very little it can't do. 

One other thing I was interested in was that the custom board featured a different WiFi antenna with a PCB routed antenna rather than the PI4 antenna. Whilst I've stopped short of measuring gain etc I definitely have noticed that I get a better connection to my WiFi from my lair! 

Final thoughts are, I think it's great. It's brilliant for me in that often I have to try odd things on a RPI for work/writing and I've wanted a more permanent set up for a while. I like that it can be chucked into a bag for trips. I think that if you have someone curious to get into programming or tinkering with project this is an excellent out of the box accessible setup for not much coin. I'm planning to tinker with getting it up and running as a controller for my CNC router and perhaps my Vinyl Cutter as well as a general tinkering machine, 

Boat building in Hackspace magazine 36!

 

So most months I update this post with a brief line describing what articles I have in the current issue of Hackspace magazine, but occasionally they warrant a post all of their own! In this months issue 36 I am really pleased to have been featured in this article about my adventures building a plywood boat. "Cysgod" the boat has been a brilliant project and as ever I learn't loads and had fun with the bonus great feeling of eventually getting to travel local lakes in a craft I built! 

One photo I submitted didn't quite make the editorial cut, but I love this photo of "Cysgod" having been commandeered by Seren, who has a decent claim on this boat having helped out on the build and also, if I am honest, it probably fits her better! 

Laser Cut Hinges

I've been making this little plinth/stand that's going to have my Super Adept Lathe mounted on it for a while and last week I took the front of the plinth to the Ffiws makerspace and laser cut the two holes. The idea originally was that it would just be a little cubby hole to store odd bits and bobs. However the kerf is so fine with the laser that I couldn't help but think it might be nice to keep the cutouts as doors. So it got me thinking about hinges! I'd seen this method ages ago on something at a maker event but had never tried the principle. 

Above you can see the component parts, all cut from 3.125mm ply the 6mm diameter hole and plug already have a nice clearance due to the laser cut. The idea is that you carefully glue the little circular plug to the solid pieces taking care not to het any glue in the mechanism.

The idea is contingent on making the holed section/arm slightly thinner than the plug, so some nice even sanding (around 12 strokes per side) gives enough clearance for the hinge to be solid enough yet still move. 

Finally gluing the final solid piece to the hinge, and again you have to take care to not get any glue into the rotating section. I think an improvement would be to create some kind of jig so that you  can set these up with longer drying wood glues which would make them stronger, but they seem ok for now with super glue. 

Glued up the cubby door side before affixing them to the main assembly. 

Casting Silicon Tyres.

I'm definitely into developing robot stuff at the moment and after the MTV robot project, where I built everything apart from the chassis, I wanted to build some chassis ideas for a smaller platform. The first attempt is above, a CNC'd folded aluminium chassis with 3d printed wheels on which are riding DIY glow in the dark silicon tyres!

I wanted to share my process, the first thing to know is that I've used some really cheap silicon, the type of silicon used in bathrooms as seen above. The important thing is that it is pure silicon with the acetic acid smell as it cures. If you open the tube and it smells very vinegary you have the right stuff!

I've been using about this much silicon per batch, it's about a golf ball size blob and is plenty for a set of 4 small tyres. To it I am adding a pea size amount of acrylic paint, and I happened in these first batches to use some glow in the dark acrylic paint. It doesn't seem (even with different colours) to matter if you put more in than a pea size amount as the tiniest blob seems to colour the silicon well. I'm also adding a few drops of glycerin, the glycerin seems to thin the silicon slightly but certainly seems to make it flow a little easier.

I simply CAD'd some moulds, they are in 2 parts and the small pip and hole correspond to ensure that the mould and the core are centralised creating an even tyre. In the photo above you can see that I've packed the mould with some of the mixed silicon before squeezing the mould core in. 

Squeezing the two parts together you get a lot of material pushed out of the sides, which you can scrape off and put into the next mould. Make sure that the moulds are fully closed so the walls of the tyre stay nice and vertical. 

Above you can see the filled moulds, I left the first set for around 12 hours before turning them out but later sets have been happily de-moulded after around 3 hours. At 3 hours the tyres are strong enough to be removed and handled but still smelt quite strongly indicating that they aren't fully cured. 

Pulling out the mould core they seperate cleanly and the tyres are nicely formed. Having made about 12 of these now I haven't had any with any air bubbles or defects. They need a little cleaning as they tend to have a little "flash" silicon around the edges but it's easily removed. The tyres are strong yet very soft and grippy. I'm planning to experiment with fitted tyres and also treaded tyres in the future but for now these tyres fix to wheels very well using a thin film of super glue. They glow nicely as well! :) 

Lil' Lights, Adventures in PCB's, FLIR and high power LED's

                        

                        

After designing the MTV robot I've been slowly tinkering with numerous add ons. I wanted to add some high power LED lights and so I bought some 1 watt white LED's in an SMD package. They offered a lot of light and I'd read that the 1 watt LED didn't need heatsinks to keep the running temperature within the datasheet operational temperature range. 

Testing them on the bench they get hot enough to be uncomfortable on the fingers so I decided that a PCB breakout that enabled them to be easily mounted but also acted as a slight heatsink was desirable. I quickly whipped up a design using the fabulous inkscape plugin SVG2Shenzhen and finished the design off in KiCAD . The PCB has a large pad that interfaces with the LED "slug" and in the PCB pad there are some via's connecting that pad to the large copper flood on the back of the PCB. This flood is under the mask so heat doesn't dissipate massively but I wanted it to just slightly reduce the temperature of the LED. When soldering on the LED I've added a small spot of thermal grease between the LED slug and the PCB pad. Finally I made sure that the M3 mount hole (3.2mm diameter for clearance) wasn't copper plated so that hopefully the heat in the LED and PCB wouldn't wick into mounting bolts etc. 

                        

I got some of the PCB made by the fantastic OSHpark  and mounted up some LED. Driving them at 1 watt is made simpler by using one of the cheap constant current capable DC-DC buck driver boards that are readily available now. They certainly are bright! 

                        

                        

I wanted to test how well everything was working and a friend kindly lent me his very nice FLIR camera. You can see a couple of things below comparing images from both mounted and unmounted LED's, firstly the PCB does indeed reduce the overall temperature a little as compared to the unmounted LED. Rather splendidly you can also see that the PCB mount hole doesn't couple and transfer the heat which is nice to know when bolting them into 3d printed parts. 

                

Above left is the front of an unmounted 1 watt LED. Above Right is the front of an LED mounted on the PCB

Above left is the unmounted LED rear and above right is the rear of the PCB with mounted LED.

                                

Above is a FLIR image of an M3 bolt placed through the mount hole of a PCB mounted LED. 

Get in touch if you are interested in getting any of these boards as I might put some on a tindie shop at some point. 

Unboxing and quick review of the Valenta Off Roader robot kit.

Quick video unboxing and assembling a Valenta Off ROader robot I won in a twitter competition!

Budget Eyewear Options for Close Up Work!

I'm comfortably slipping into that age range where eye strain is easily found and when the "ready reader" glasses are not too far away at any given time. Although I have always used lenses and loupes for close up work I am wearing them more often for a an increased variety of tasks. I've been quite happy with my choices until recently when wearing ones with a traditional nose arms and pads have started to annoy my nose and cause a bit of soreness, probably due to wearing them and glasses more often! So in a fit of random old maker blogging I though I'd do a round up of my crop of cheap close up work systems!

First up above (and modelled below) are my oldest pair which are essentially a set of loupes on a wire frame with some LEDS. The LED's on this type are rubbish using none rechargeable little coin cells with fiddly little switches and inside pretty poor quality plastic cases that promise to be move-able into any position but rarely stay where you want them to be! The loupes themselves are pretty good and powerful but only put stuff in a working range/focus about 15mm away from them. Far to close for soldering etc but actually can be very useful for looking at tiny mechanisms or indeed for hunting solder bridges or inspecting small joint on PCB's. The loupes can be rotated away from the eye and so you can flip them on of off without removing the frame. They aren't that heavy so can be worn for long periods. 

Next up, below, is these white plastic frames with interchangeable lenses, mine came with a set of 5 lenses promising a range of magnification from 1.5 x through to 4x. The lenses themselves are in a separate box and snap into place and can be rotated which is nice in that you can adjust their position relative to your eye. I find the 1.5x magnification can still return me a working distance of around 20-25cm which I find quite nice in terms of SMD soldering and other small work. They have 2 white LED's mounted above the lens and you can tilt the LED mount down and up to change the angle of them which works well. These take 3 AAA batteries and they are mounted in the front of the frame. I've found these brilliant for a long time but noticed that the combination of a standard glasses type frame that balances over your ear and the batteries at the front makes them feel front heavy and that they might slip off. They never have to be honest but these are the ones that of late, due to increased usage and reliance on them have started making my nose a bit sore! I've found these available online for between £9 and £15.

As previously it seems only fair to let the resident supermodel show off how hot these make you look. :)

So finally we come to the new kids in town! Pictured below these are similar to the last pair but I wanted to try a set that had a headband arrangement rather than a spectacle type set up. This set have a nice around 40mm wide padded and adjustable headband which can be set up to suit the wearer. They offer lots of support and the whole of the white assembly can be rotated up and down without removing the headband. They have a set of lenses similar to the previous set (in fact they are interchangeable) but the 1.5x lens is permanently attached in the frame and you can add more lenses behind if needed. They also have this pop down loupe which I haven't really found use for as yet but it amuses me in how brilliantly dorkish it looks! This set have 3 LEDS and they are powered by 3 AA batteries. You can tilt and adjust the LED up and down and side to side and you can also remove the LED and batteries out of the headband as a complete unit. If you don't want this extra weight on the front and don't need the lighting this is a nice feature! The LED's in this set also have 2 power settings which I guess offers more flexibility. I've found this set online between £12 and £25 so shopping around is definitely worth it. 

This final set have totally got rid of the nose irritation the previous set started to give and they also feel way more secure on your head and are pretty comfortable for a long close up session... Again.. I leave it to readers discretion to work out how "cool" they might make you look! 

 

A Day off and a Spoon Whittle!

Decided today to take a day off all projects and stuff. It's been a busy couple of weeks and I needed a slow day pottering. The trouble is I am easily cajoled into making stuff! My son Harri (10) is currently a bit obsessed with bushcraft and Ray Mears and he was showing me in the Ray Mears book the section on whittling. He can baton wood and is practicing and its a nice thing for us to do in the garden together. 

So I ended up making a small spoon! I made it from a batoned in half piece of ash from the garden pile and I used the Mora Heavy Duty carbon knife to rough it all out. I don't own a spoon/bowl gouge knife so I used an approach thats in Rays book amongst others, that of placing a small ember from the fire on the spoon to burn out the bowl shape into the blank. I then made one concession to modernity in that I used a stamps worth of sandpaper to clean it up and finish it. It's certainly not great, but is a nice object for a first go and it's nice to sit doing things like this with my kids. 

 

10 Minute Make, a crappy ts100 case!

The fabulous TS100 soldering iron (I posted a review of it here) comes well packed in a cardboard box which would be fine as a case apart from the foam inside is cut to hold the body and the tip/element separately. I've been meaning to make or print or CNC a slick case for it that would hold the iron as a complete unit, but it's one of those jobs I never seem to get around to. 

Randomly this week my father in law gave me an old tool (a small spirit level) that was in this sort of glasses case with a nice rusty patina! I also today had to take the ts100 out with me to a space I am borrowing for the boat building project (more on that soon!) and so I quickly mashed up the old foam shapes from the original packaging into the metal case! I'm filing this in the "I'll replace this with something better made at some point" pile... I bet its still in this case in 5 years :)

Swann Morton Retractaway Review

 

I've loved Swann Morton for years ever since using the old school burnt orange model makers blade holders they made for many years as a kid. I recently came across the "retractaway" blade holder in a makerspace toolbox and was immediately impressed with how it felt in hand and secure the retracting mechanism was. So I ordered one and have had it for a couple of weeks. It's a pleasure to use and after years of scalpel holders in toolboxes that may or may not retain their cap/cover its nice to know this is safe when chucked in a box. 

Not much to say technically apart from its only designed to be used with a small range of blades. 10, 10a and as luck would have it 11 and 15, the latter of which is my favourite and is the fitted blade in the image. It has 3 idents on the retracting mechanism, closed, half open (the working position) and fully open (the position for swapping blades). Retention is great albeit with a slight bit of side play in the blade assembly. In usage though this rarely causes any problems and it's capable of very fine work.  

FreeCAD Laser Cutting Addon Workbench

Just uploaded my latest video tinkering with FreeCAD in which I explore how to install add on workbenches and we install the Laser Cutting Interlocking workbench and take it for a spin using the automated tools for adding interlocking tabs and holes to our models and how to automatically lay out 3d assemblies into 3d parts for export to an SVG.

Inkscape SVG to FreeCAD

On a bit of a roll with videos this week! After I put up the video about the longworth chuck mechanism as a robot gripper, a follower on twitter enquired about how I had approached importing an Inkscape SVG file into FreeCAD (which I had done due to laziness as I didn't want to totally redraw the longworth mechanism)! Seeing as he asked nicely I did this little walk-through. As I mention in the video, its a useful fix but its definitely preferable to only use this when needed as directly working in FreeCAD using sketches is more dependable. Hope it's useful. If it is do feel free to show your support via my ko-fi page here!

Longworth Robot Gripper

Devout long term readers of this blog may remember my longworth chuck design and build which got re-hashed relatively recently into a dividing tool (as seen in Hackspace magazine issue 29 article on dividing which also has links to the project files on thingiverse). I've been interested in its application as a robotic arm gripper for a while and decided to prototype a servo driven one which might be able to be mounted on the opensource Modular Tracked Vehicle (MTV) robot as featured again with all the design files linked in hackspace magazine issue 32.



I'm pretty pleased with this first pass prototype (as usual with heaps of hot glue etc) and I'm going to continue to develop and refine it a little as I think it could be quite a fun gripper type for people interested in robot challenges etc to think about using. Check out the video above to see it in action and feel free to subscribe to the Youtube channel.

3d Print Welding and Fibreglass

New little video I've edited today chatting about some 3d printing techniques, welding parts with a 3d printing pen and also embedding fibreglass into prints to make very stiff components.

FreeCAD video part 2

I've really enjoyed making these videos for the Ffiws project from Arloesi Gwynedd Wledig and its been a welcome opportunity during lockdown! Building on Part 1 we move to the part design workbench and build a part using the "body" concept, mapping sketches to faces and using tools like the pocket tool and hole tool to create a nice model. The model is a part of the larger MTV robot project I built and wrote about in Hackspace Magazine.

Printing Pinion Gears for the mini lathe.

I managed to strip one of the pinion gears on the mini lathe a while ago and I was surprised that I couldn't find a 3D model of them to print, particularly as I'd seen a lot of gear wheel sets for the mini lathe on thingiverse and elsewhere (I think this is an indicator that perhaps other people aren't as idiotic as me and don't strip their pinion gears)!

 Today I set about sorting it with some 3d printed replacements. I used the involute gear tools in the "Part Design" workbench of FreeCAD which I am using more and more as my go to CAD environment. It's a pretty easy tool to use so long as you know the "module" of your gear which can be worked out as it is the pitch circle diameter divided by the number of teeth. Counting up the teeth on the old stripped gears showed they were a 25 tooth and a 20 tooth and the overall diameter was close enough to make me feel that the pitch diameter was going to be the number of teeth in mm giving a module of 1. I'd read online that the mini lathe gears all ran at 20 degree pressure angle. A quick bit of calliper work on the hole diameter and we were ready to CAD!

The results are great, printed in PLA at 35% infill I've been running the gearbox for a couple of hours and all seems well. I've printed up a few spares and chucked them in the box of gears. As I couldn't find this set of gears online anywhere I've put it up on thingiverse as a project so hopefully it's of use to others. You can find the files and the print settings here. 

10 minute make, Filament reel stand!

So whenever I swap to use a big reel of filament (2.3kg ones) I always end up concocting an elaborate balancing of stuff to hold it on! I've been known to have 2 piles of books with a piece of threaded bar balanced across them before now. The other day I was about to scrap some small stands I'd made that could hold a 25mm dowel between them I'd originally made as a jig to help fibreglass onto a tube. I quickly realised with a larger base and a shorter piece of dowel it would fulfill my filament holding needs. I just use a slightly undersize "o" ring on the dowel to stop the reel from drifting along and off the stand. Perfect!

Hackspace Magazine Issue 32, Opensource MTV robot!

Normally when each months Hackspace Magazine comes out I update this "keeping track of my articles" post, do a few tweets and move on. This months magazine has a project I put together that feels worthy of a little blog post all of its own though! I was asked to write a tutorial using a cheap tracked robot chassis kit (just the wheels, chassis, motors and tracks around £20-25 online) on how to build a budget robot. I decided to go a bit further than just cutting a couple of boards to mount stuff to and came up with an entire modular system built up on the cheap chassis from 3d printed parts. Whilst this particular robot is referred to in our house as "red one" the whole modular robot project is called "MTV" short for Modular Tracked Vehicle. All the modules feature M4 holes on 10mm centres so that modules can be mounted in lots of places and it can all be reconfigurable perfect for adding experiments and other doohickies too! I did all the 3d work in FreeCAD so that it is made with opensource and free tools and also all the files are published in a project repo on gitlab. I'm not going to give you the link though, you have to go download the (excellent imho) magazine, read the articles and find the link there! Check out hackspace issue 32 here.  I'd love to see others tinkering on this so do feel free to join in, merge requests are open on the repository and do get in touch if you build one!