Tuesday, 6 April 2021

Repairing the best worst extractor lamp!

Not sure if this is a blogpost or just a cautionary tale, but anyway DON'T BUY THIS SOLDERING EXTRACTOR LAMP! With that said... here is my tale. I wanted a small solder extractor and I saw these extractors built into a angled lamp, running off USB power they peaked my interest and I handed over £40 for one online.  On arrival I unpacked it and put it into use, it was OK, not the strongest extractor by any standards but my solder area is under a Velux window and it has enough of a draw to move the solder fumes away from me and out of the window. On the cable to the USB plug it had a controller with 4 momentary press buttons on it, you could switch between 3 "colours" of LED lamp, all shades of white, one a "cool white" one "warm white" and one that was a combination of both. You could ramp up and down the light level in steps, but I always had them on full power. It also had a fan control to set the "power", this was always on full and you could tell that when the fan was on it was starved of current a little as the light would dim. If you turned the lamp off the fan would speed up! 
Anyway, the control system lasted about 2 weeks! I came to it one day and it had failed, I couldn't turn the lamp on and although I could run the fan I couldn't adjust it and randomly an LED in the controller was stuck on. I did really like it though, I liked being able to clamp it to my workbench and drag the lamp and extractor really close to work so I decided to try and fix it.

Pulling the controller apart and a bit of probing with a multi meter I realised that basically the control system made or broke the negative power rail and when the microcontroller was operational was probably PWM'ing the power to each circuit. I realised that I could quite simply wire in a switch for the fan and for the two LED light rings. I wasn't bothered about having both the LED lamps on at the same time. So a quick bit of soldering and then a small 3D print and I have a simple but working "controller" back on the lamp. I reattached the USB cable as I have lots of USB outlets and also it's nice that it can run off a battery pack if and when we get back to maker events or rocketry in fields! 

Tuesday, 23 March 2021

Ultimate Makers Case? Droneguard CS400

Recently I got around to building a 270mm "Robocat" quadcopter chassis I bought a few years ago that sat on the project pile. It's an interesting time to be building quadcopters that are going to weigh over 250g as now these require registration and insurance, both of which I have. However as a knock on it means that there are a lot of bargains around in terms of accessories for larger quads as people move towards lighter ones. Notably larger slightly older fpv cameras etc can be had for bargain prices. Another area where bargains abound is cases. As I have this up and flying I wanted to be able to store it and also walk it in to nice flying areas. Looking around for a suitable backpack and I came across the Lowe Alpine range of DroneGuard packs. The CS400 is a larger one in the range and a few years ago was a flagship case for them.

It's made from that kind of semi rigid material which wouldn't survive me standing on it but would survive a heavy bag being chucked on it or indeed being dropped a short distance. It has a stack of attachment points on the outside (similar to a molle system) and an outer slim pocket, not much can go in there, a phone maybe. Inside is where it gets interesting, all the internal panels and small bags can be removed and repositioned, the panels and bag have velcro that can adhere to any part of the internal case so it's very reconfigurable to its contents. 

In the lid side is a small thin - I'm going to call it a briefcase - which has an excellent organiser section on the front for holding small parts, tools and cables. This briefcase can be removed which leaves the lid to act as a great area for working in when in the field as it's steep sides mean you aren't going to lose a screw or clip in the grass. 

Whilst we have only walked around a km with this laden, it's pretty comfortable to wear as a rucksack, and the straps have a clever latch system that allow them to be removed. You can connect the straps together to make it more of a shoulder bag type carry. 

Finally, the best bit! Remember I said that these where a flagship product a few years ago? Well it seems the original RRP could be up at £130, I got this one online, brand new and delivered for £28. It should give good service for the quadcopter, but I can also imagine using it a lot for rocketry stuff and other maker events carrying all kinds of kit, well protected, into cool places. 

Thursday, 25 February 2021

New Rocketry CAD tools: FreeCAD Rocket Workbench

In my never ending quest to get more opensource stuff around rocketry going I posted over at the FreeCAD forum about a concept for a Rocketry themed workbench. It seemed like it would be a good fit and that it might be an interesting area for developers to work on. I explained how I'd often used Openrocket to design and simulate a rocket design and then, quite often, I found myself copying dimensions into FreeCAD or sometimes OpenSCAD to create 3D objects of nosecones, centring rings, fins and more. I suggested that automating some of this would be a good starting point, but that also the sky was the limit, ultimately it is *possible* to recreate something like Openrocket or Rocksim in FreeCAD, with the benefit then of any design is auto-magically in a CAD format for other techniques to be applied. FreeCAD already has a wealth of tools that can be leveraged at rocket parts, from 3D printing mesh tools, to CNC toolpath work, through snazzy computational fluid dynamics tools,  FEA and more. Hell, there'ss even a glider workbench for designing gliding parachutes within the community so the end really is limitless!

What happened next was utterly brilliant and testimony to opensource culture! People got interested and one chap, Dave,  (AKA DavesRocketShop ) got stuck in. Within a couple of weeks we now have a rocketry workbench released with some useful tools already up and running. Also there is a tantalising roadmap of exciting features to come. 

The first release when installed as a workbench gives you some parametric tools to create rocket air-frame components. Nosecones in all the common geometries are all there, Haack, VK, Ogive, Parabolic series, Power series etc. Transitions are similar in choices and there are tools to create body tubes, centring rings and bulkheads. It's really straight forward to begin to assemble great parts that can be adorned and edited using the entire suite of tools FreeCAD has to offer. Fins, in the first release, are limited to trapezoidal designs but there are a wealth of parameters to play with and it's trivial to auto generate aerofoil geometries etc.  The rocket workbench is already available via the addon manager which makes installation and updating a breeze and on the forum thread the mighty Dave is occasionally releasing manual install versions for those of us keen to try experimental features. 

Dave is currently working on importing parts from the openrocket databases. This is really interesting as all the common manufacturers parts are in there, so if you want a particular Estes replacement nosecone, or to upscale one for some crazy project this will be but a click away! I'm most excited about that there is a plan to allow the workbench to import Openrocket, Rocksim and RASAero files, whilst that may be some way off it really opens up some astonishing opportunities for rocket designers. Also having got to grips with the technical drawing workbench in FreeCAD I am looking forward to being able to document my designs well, important if one day I go for L3 HPR certification. 

Finally if you are new to FreeCAD but want to try FreeCAD I'm writing a reccurring series for Hackspace Magazine on FreeCAD and it started back in issue 37 here

Sunday, 7 February 2021

Cheap Small FPV Quadcopter Conversion

I've been getting back into a few long stalled projects including building up a Robocat 270 quadcopter kit I've had for ages on the build pile (will post on that soon). the reignited interest in quads has made me want to try and learn to fly First Person View (FPV). The Robocat needs a few line of sight flights before I commit to rigging it with FPV and so I wanted to learn on something smaller and cheaper. My very first quadcopter was this Syma X11 a small brushed drone that is a brilliant little stable flyer to learn on. There was a version sold with a camera (non FPV, 0.3 megapixel and micro SD) but all the Syma X11 bodies are the same and on mine there was a blanked off lens area and a void where the camera would be. I'd picked up a set of cheap Eachine goggles off eBay and so I bought a tiny Eachine TX06 split FPV camera and video transmitter (VTX).  As the X11 is a little airframe I am used to, and , as I felt I could get the TX06 rig in it, it felt a good option for a cheap small learner FPV setup.

Flipping the X11 over you can see the lens cover which was the target area for the camera. Undoing the 4 screws allows the lower body and the battery cage to be removed. 

The battery cage (the white piece) can then be removed with 4 small screws. I realised that the VTX would sit happily underneath the battery cage and that the small antenna could be pushed through the rectangular hole you can see at the back of the body shell on the left. On the white battery cage above I needed to snip of the square moulding seen at the front in the picture above. After removing the small fake lens in the body I snipped some plastic to widen out the hole for the camera. 

You can just make out in the image above that I've places a small piece of double sided pad between the camera and the battery frame and you can see the amount I have trimmed off the battery cage and the body on the right of the image. 

Powering the camera and VTX I simply trimmed the connector off the TX06 and soldered the wires onto the pads where the LiPo connects to to the board. I've managed to fold the wires out of the way and the battery slides into the battery cage as it did before. You can tell there's a little extra weight in flight, but it really isn't an issue as in stock form the X11 had a reasonable flight time. Now to get used to the wibbly wobbly world of FPV! 

Thursday, 28 January 2021

My New Laptop; Starlabs Star Lite MkIII


I've owned heaps of laptops, probably over 20 if I sat down and wrote a list, and almost all of them have been 2nd hand. In fact I've only ever bought a couple of laptops new and, until this one, the Starlabs Mini Lite MkIII, I've never bought bought a new laptop with factory installed Linux. In fact Starlabs offered a list of Linux distributions that could be preinstalled. I've used lots of different distributions over the years but I've become a bit lazy with them and tend to just stick to Ubuntu. I know, it's a bit bloated, but I like the interface and stuff seems to just work for me. 

So any company that's creating Linux laptops gets some attention from me but what really made me want to own one and support Starlabs is that they are pretty great in terms of repair and hacker friendliness. So for a start, opening the Star Lite doesn't void the one year warranty. HELL YEAH. Secondly they have made a point of making their products simple to work on and the only tool you need is a Phillips screwdriver. I love this stuff, it's important in terms of actually owning the things you own and it's important in terms of keeping hardware alive longer. 

So to the Star Lite MKIII. It's great!  It's small and super thin and has an 11" screen. I've always lent towards portables/UMPC and road warriors rather than larger desktop replacements so it's perfect for me. Specs wise, it's interesting, with a Pentium Silver N5000 processor that on paper doesn't look like the faster thing ever but paired with fast RAM and a blazingly fast star drive SSD, so far this machine absolutely zips along!

It's all aluminium chassis wise and super lightweight, yep it's definitely one of those laptops that falls into the "I'm checking my bag twice to see i it's actually in there". The keyboard is good, which I think as my daily driver for years has been an old Thinkpad X220 with arguably one of the best ever keyboards, is fine praise. The keys have a nice stroke length and the keyboard is back lit (with a couple of adjustable brightness levels) which is a feature I've wanted on a daily driver laptop for a while. The matt screen is also worthy of mention, it's a total joy! I find it much less fatiguing on the eyes than other screens. 

So coming from a background of usually installing Linux on machines it's nice that seemingly everything works well on the Star Lite. I know that might sound odd, but I've usually had something on a Linux'd machine I've needed to sort. A small script to stop Bluetooth turning on at boot or perhaps the hardware keys for screen brightness have needed solving etc. So far on the Star Lite, none of these things apply. 

In use I've mainly hammered it with browser tabs, multiple terminals and a fair bit of Libre Office Writer which I do most of my writing in. I've also been playing with the FreeCAD app image on it and it's actually a very good experience and certainly capable of handling most of my CAD needs. I imagine, if you are designing hugely complex geometries and assemblies this may change, but for my needs most of the time it's perfect. Battery life is good, not sure I'm getting the stated 7 hours, but certainly 6 hours which will do me. All power related stuff, hibernation, wake from sleep, are all working as they should as well. 

So rounding out this... yep, they get my vote! At £400 this is a cracking little machine and if you want a laptop that replaces the windows key with a "super key" you should buy one today!

Wednesday, 20 January 2021

Playing with the Raspberry Pi Pico!

I've been incredibly lucky to get to play with the new Raspberry Pi Pico in pre release and, in short, it's rather brilliant! First up, this new board contains custom Raspberry Pi silicon, the RP2040 chip, which will also be sold as a standalone product for people to develop products/systems/boards with.

The Pico is set to retail at  less than a £5er and you'll want to check out this page for the full spec and the pin in/out of the Pico but the highlights are;

  • Dual-core ARM Cortex M0+ processor, with clock running up to 133 MHz
  • 264 KB of SRAM and 2MB of flash onboard
  • 26 multi function GPIO
  • 2x SPI, 2 x I2C, 2 x UART, 3 x 12bit ADC, 16 PWM channels
  • 8 x PIO Programmable state machines

  • It  has USB Host and Device, compatible back to 1.1 and it's programmable via drag and drop using mass storage mode. If that last line didn't make sense, put simply, you create some code, attach the Pico via USB (whilst holding down a button)  it appears as a drive and you drag your script file to the Pico and it is automatically installed! Simple!

    Language wise there is a C/C++ and  a port of Micro Python and I've played a little with both, working through some of the examples in both C/C++ and also Micro Python. All my tinkering has been done using my Raspberry Pi400 and it's worked excellently as a pairing! 

    I started following the Getting Started PDF for C/C++ and installed the SDK/ toolchains. The guide walks you through installing everything you need from the terminal and steps through how to make and build the examples. Many will opt to edit and create code in something like Visual Studio (again bundled into the Rasbian image) but for my simple tinkering I opened some of the examples using nano, tweaked and then rebuilt them in the terminal. You honestly don't need to be a terminal guru to get to this point, simply follow the documentation. The resulting tweaked examples, when built, create a .UF2 file which you can drag and drop to the Pico which flashes incredibly quickly. 

    Perhaps more accessible for some is the Micro Python or "Pico Python"route, the first task here is to drag and drop the Pico Python firmware onto the device, for convenience a pre built binary is available on the Pico Getting Started page. Also in the getting started with Micro Python on Pico documentation there is a guide for you if you are keen and want want to build your own binary. Flashing the micro python firmware to the Pico is another simple drag and drop operation and you can, of course, swap between C/C++ and Micro Python by re-flashing.

    Following the micro python getting started guide it walks you through interacting with the REPL using minicom within the terminal which is fun to tinker with. There's a decent walk through of all the examples in the micro python repository in the documentation. This includes examples that use most of the Pico's features, PWM, UART, SPI, PIO , but there's also examples for things like interrupts, and additional common sensors, Neopixels and LED's. 

    Towards the end of the Micro Python guide there is a section on setting up an IDE, Thonny, to provide a nice environment for working with the Pico. Thonny is a nice simple IDE that's again bundled in the Raspbian OS, it's pretty straightforward to set up and get going and you can work directly with the REPL via a shell window or you can save and deploy scripts temporarily or with persistence to the Pico.

    So! My thoughts, it's great, a low price, really fast and well spec'd micro controller that at launch already has a heap of resources and examples, I'm sure that at the price point it will attract a mass of users and a strong community which will create and share lots of wonderful projects. I can't wait to see it grow!

    Thursday, 14 January 2021

    Repairing for Thriftyness! Zoom H4n tiny repair!

    I'm always repairing stuff and find it a really rewarding thing to do for all kinds of reasons. I've been thinking about how repairs have different things that drive the desire to repair. Many times I repair because I need to use a tool that I've managed to break and can't wait for a replacement, sometimes I'm repairing something I've made, a crashed rocket or ripped parachute. Sometimes repairs are emotional and nostalgic, repairing an item I have an attachment too that is irreplaceable. Sometimes I feel repairs are important in terms of heritage, particularly older tools/ lathe etc. Anyway... today I was thinking, sometimes I repair because I am thrifty!

    I particularly wanted one of these zoom H4n audio recorders as I wanted to explore a particular feature they have that's slightly different to others. They are an older model now that were about £250 originally but now can be picked up in good condition for about £100. However you can often find them cheaper listed with a bit of wear and a few faults. This one was listed with a few cosmetic scrapes, an intermittent fault on a button, and the SD card slot cover missing.... it was therefore much cheaper! 

    On arrival a quick blow through the case with some canned air has cured the button press issue and it's always worth searching ebay for people selling scrap/spares/repair versions of your item. I managed to find an entire right hand side chassis component for £3.20 complete with the SD card slot. A quick swap and it's not quite as good as new, but it's 100% functional and ready to go! For the repairers out there these are pretty easy to work on, no glues and standard screws!