ramblings of an electronic engineer.

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Linkdump: June 2015

Nintendo Surgeon | XKCD

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Small Victories

Upon writing this I’m feeling pretty tired from taking stocktake all week at my work (we have a lot of stock). So while I had grand plans this week to get my act together and take some pictures for blog posts, continue writing said blog posts, working on projects etc… the net sum of what I have achieved is, well, less than satisfying, mostly consisting of sleep! To spite my unproductive week I do count one small victory in the fact that I finally worked out how to install a piece of software called GNU Radio on my Ubuntu (Linux) drive. Previously the process for installing GNU Radio has alluded me (I haven’t really used Linux too much or had to install programs on it) ending up in various error messages.  However tonight I found out what the issue was with my prior attempts and finally it is all working (FYI I was missing the pesky “sudo” command and in hindsight the process is really simple). As I said a small victory, here it is running.

Gnu radio setup

I’ll be using GNU Radio in future posts to interface with my software defined radio and do some interesting things but that’ll have to wait till then.

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3D Printering: Upgrade Time

My 3d printer looks a little different now after a few hours of work tonight.


The reason been is after experiencing some issues with warping of a few prints I decided it was time to upgrade the build platform to a heated bed.


Unfortunately while the new heated bed is all installed, as luck would have it I can’t use it yet because of lack of foresight on my behalf. To power the heated bed the powerpack supplied with the printer is insufficient and a 500W computer ATX power supply is required instead. This wouldn’t have been a big issue a year ago since I used to take computers apart and had a stockpile of spare parts (including power supplies) but unfortunately past me I decided that the spare parts I had collected were not going to be used anytime soon and therefore to save space should be thrown out.

Hence my current situation

So now I’m on a mission to try to find an appropriate PSU before the weekend so I can start printing again, without any warping issues. But realistically I probably won’t get it all sorted until sometime next week. Wish me luck.

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3D Printering: Printrbot Simple Metal

I’ve been fortunate to be able to use my work 3d printer for a while to print some parts for projects however I felt it was about time to get my own so I can print things on a more regular basis not impeding on my work’s schedule. To be honest I’d been thinking about buying a 3d printer for probably a few years and my experiences with been able to print things at my office and see it’s potential first hand probably tipped me over the edge with getting one or at the very list contributed greatly.

Since I’d been following the 3d printing scene for a while I already had a pretty good idea what machines were on the market and which designs were out there that you could build yourself. To spite almost deciding to build an open source reprap machine I ended up going for a commercial pre built option mainly because of the amount of time it would take to set it up and get it running, the price point and the fact it comes with a warranty.

Meet the Printrbot Simple Metal


At a glance the printer’s specifications are as follows:

Build Volume: 15cm³

Print Resolution: 100 micron

Print Speed: 80mm/sec max

Filament1.75mm PLA

but specifications in and of themselves aren’t really interesting but rather what you can do with them…


Judge me by my s̶i̶z̶e̶ lack of appendages, do you?

After finishing calibrating the printer and printing the fan shroud, naturally the first thing to print was a yoda head, the beloved test model to test and compare printers with. I’m pretty happy how it turned out, there were a few dags (yes a technical term, well at least at my work) that required cleaning up with this print but not bad!

The printer however isn’t without it’s faults, below are examples of two of it’s major downfalls. The first is warping of large parts due to the lack of a heated bed. Printing with a brim will help mitigate the issue but not every time. Fortunately there is a heater bed upgrade for the printer which I’m going to order soon so this can turn out to be a non-issue. The second issue I’ve had is trying to print articulating joints on models. Some joints are all good, others not so much. I suspect a contributing factor is the clearance around the joint but I’ll need to continue testing further to nail down the issue.


Warping on bottom of part


Broken articulating joints due to layers fusing together

Moving past these two issues the printer can do some amazing prints. Here is a replica lightsaber I printed in 14 parts over 2 weekends then assembled. Also below a little sneak peak of the next prop I’m working on. And yes you can be expecting some posts covering both of these builds in the future.


A true Jedi always forges his own lightsaber!


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The Martian Trailer Released!

I’ve blogged on previously on the book The Martian (which was my favourite book I read last year) and also mentioned that it was going to be made into a movie to be released this year. Well finally after much waiting a trailer had been released! Go have a look

From watching the trailer I’m optimistic that’ll I’ll enjoy the movie and that it will make a good translation from the book to the screen. Having said that I am optimistic about a lot of things so we shall have to wait to see how this one pans out (:

I should go reread that book now.

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SatNOGS Build: Introduction

With the sound of the z axis retracting on my work’s 3d printer after finishing the last of one on many parts I’ve been printing, I think it’s about time I announce the project I’ve been working on in my spare time over the past month (this project is also unsurprisingly partly the cause of a lack of content here which I hope is going to get better as I get back into the swing of things).

Last year Hackaday ran a competition called the Hackaday Prize which encouraged participants to work on open source hardware (and software) projects competing to win a trip to space. Anyway a project called SatNOGS won the grand prize with their Open Source Networked Ground Station for talking to satellites in Low Earth Orbit (LEO). It’s one of these ground stations (essentially antenna rotators) I plan to build from their open source designs.

So to give a bit more of an introduction to the SatNOGS Project it was created by members of a hackerspace (now the Libre Space Foundation) located in Athens, Greece. The team aimed to create a system of interconnected satellite antenna receivers that can be used to schedule observations of satellites as the fly overhead. With enough ground stations distributed over the world the system should be able to provide (almost) 24/7 coverage to fulfil schedules observations. Hence the overall system concept is as below.

The system can be further broken down into 4 components:

  • SatNOGS Network – a observation, scheduling and discovery server
  • SatNOGS DB – transponder information website
  • SatNOGS Client – imbedded system that communicates with the network to receive an observation, record the data and send the data back to the network
  • SatNOGS Ground station – the hardware and electronics that is used to complete the observation (what I’m building)

The SatNOGS team has created a solution for each of these components however the state! Is also designed to be able to implement existing hardware like commercial antenna rotators.

Getting down to the nuts and bolts of it all below are some pictures of the ground station and antenna they have designed and that I plan to build. Almost all of the parts that are required for the build (rotator only at the moment) I have either purchased or 3d printed using my work’s ultimaker 2 so I’m pretty much ready to start assembly save for a few electronic components which I’m waiting to arrive. I still however need to decide which antenna I’m going to build and what I’m going to do in regards to the tripod (I’m thinking I might be able to design an interconnect between the rotator and my Manfrotto tripod).

There are a few reasons I’ve decided to build this project in particular, the first most obviously been SPACE!. I feel that this project takes a large step to making space accessible for people who aren’t part of a large company like Space X or NASA :). It also has the advantage of making any data observed with the system to be freely available and open. Secondly I’m a huge fan of open source projects with this one been no exception. Creating open source projects allows one to learn a lot about the inner working of things and with experience contribute back to the project. And finally on a more selfish note working on this project means that I don’t have to write any code of software which while I’m capable of doing (at least in C or assembly languages) I don’t really want to have to devote the time to doing so. Having the code taken care of also means I can spend for time trying to improve the hardware side of things and contributing back to the project.

For more information about the SatNOGS project please visit their website or git repo.