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The DSO-138 Oscilloscope Build

So I thought a few months ago that I would give the DSO-138 Oscilloscope kit (approx. £15) a go. I wanted to get some more hands on experience with PCB’s and soldering whilst studying my Electronics Engineering Masters.

The Build

The kit is pretty straightforward with everything marked up and decent instructions. I would certainly recommend, as many others do, testing each component individually prior to soldering.

A few good YouTube videos that are worth a look prior to and during the build are:

https://www.youtube.com/watch?v=OISEu-Bm8_s

https://www.youtube.com/watch?v=4Lsp5YZgsZU  

As you might be able to see from the picture, my soldering is a little ropey but everything felt strong and the board works fine with no issues. I only had some cheap solder with me, which took a while to melt onto the board in places and certainly something I’ll avoid in future. All part of the learning process!

I would also make sure that the ring you solder in for the test signal rises up quite high. A problem I have now is that because I put in a small ring (a cut off from a resistor leg), it doesn’t match very well with the hole in the case for it (vaguely see from the below picture, second hole from left). This is not a big deal but worth mentioning if you are putting it into a case afterwards and may want to use the test signal.

Circuit Troubleshooting

After initial soldering and assembly, I tested the circuit and it didn’t work! I checked the voltages and they looked ok to start with but were -ve and very low in some places. This taught me about PSU polarity, a really basic concept in hindsight, but not one I had come across before on a practical level. I figured this out through the good old use of asking a forum! 

My issue was that the PSU I was using was one I use with my guitar pedals, which are -ve polarity and I needed a +ve polarity PSU for the DSO-138 (I didn’t realise this at the time!). Fortunately for me, there was a protection diode in place (probably why my voltages were so low as I guess that was leaked voltage). 

That was basic lesson 2) of troubleshooting........what protection diodes are and how they work. Again, simple, basic and key and this information will certainly help me in future if I decide to design my own circuits - and save me some components! 

After changing the PSU to a +ve one, all was fine and the board worked with the correct voltages.

Acrylic Case

I bought a case for the scope off EBay (for about £5) to finish off the project. There are no instructions so I used this video to help:

https://www.youtube.com/watch?v=FlniY41j7B0

One thing to watch out for is the Power Inductor. On the version I bought, it is quite big and doesn’t allow the case to go together correctly. To right this, I filed a bit extra out of the case layer that obstructed it and it then fitted fine.

The case available (I don’t think they are strictly official?!) is strange as its kind of like a perspex puzzle but it does the job and saves leaving an exposed circuit board as a finished project.

Firmware

In terms of the Firmware, it does come with working firmware but to update to the latest version I bought a cheap USB to TTL adapter for about £2 (again from EBay). It was a bit of a fudge to do but I used this video to help guide me through:

https://www.youtube.com/watch?v=fDtqO2wDdHk

Project Review & Final Thoughts

I really enjoyed this project. It was the first I had done like this and learnt a huge amount in the process whilst feeling I achieved building something that worked. I was glad that it worked after very little troubleshooting which is great to keep the momentum going for future projects and added verification that my careful, slow approach and testing everything paid off!

I’d certainly recommend the kit for people in my position wanting a bit of hands on experience whilst actually building something useful. I think the range of the oscilloscope is up to 200kHz so it’s not hugely useful on a practical level (nor is it likely to be extremely precise), but it is a cool demo toy and might come in handy for experimentation purposes in the future!

In total (not inc things like solder), the project cost was approximately £28 (£15 for the kit, £5 for the case, £8 for the PSU). 

I realise now (after purchase) that the particular kit I bought, is actually a knock-off from the original. The original is made by JYE Tech (http://www.jyetech.com/Products/LcdScope/e138.php) so please buy from there if you are interested in the kit as they are the original designers!

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Just walked into the bathroom and this has happened! #xmas

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Just spending Saturday moring doing some errr #maths yeah... (at Manchester, United Kingdom)

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The only band ever #alexisonfire are back! #aof #randl15

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St James' Park again! #arsnufc #afc #bpl (at St James' Park)

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I gots a new toy! #arduino #electronics

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Fifa 15 Gameface

A while back i posted up an article showing my results of Fifa 13’s Gameface feature for my custom character/pro built in the game. With the 2015/16 season having just started, i thought i should finally catch up and post what happened when i tried the Gameface feature on Fifa 15 (i didn’t buy Fifa 14). I thought the jump in the technology produced some staggering and impressive results in 2 years and what was a gimmick, slightly funny thing to do, has now become a bit more serious when it comes to ‘getting you in the game’!

Here are the photos i used, along with the resulting interpretation from the game, check out my Fifa 13 Gameface post to see the step forward.

Personally I think that EA should continue to develop and refine the Gameface technology as in my opinion, it multiplies the connection a gamer has with the character/pro they have created in the game as themselves hugely. No longer do I have to scroll through face presets and sliders tweaking eyebrow heights and cheek definition, just to end up with a character that still looks nothing like me! Not a life changer, but I was really impressed with this feature and thought the results were interesting enough to show off!

[lawrenciumbc]

How Dangerous is an Uninformed Vote?

This is a topic i’ve always thought about and wondered, out of all the voters going to place their vote at the general election, how many are voting for a party or candidate with what might be considered a ‘weak’ reason? For example, anything from; the colour of the party is their favourite, the party leader seems the ‘coolest’ or ‘its the party my parents always vote’.

You would like to think that people who don’t care don’t vote, though we are constantly being told ‘if you don’t vote, you can’t moan’. To me, that statement is ridiculous. If you don’t vote, you don’t get what you want, but if you vote with no balanced consideration then you probably risk not getting what you want even greater.

The worrying thing is that I am willing to bet that there is an alarming number of people who vote just ‘because they can’ and with no political motive or knowledge behind their decision. The knock on effect is obviously the potential to have a party in power who a large number of their votes were from people who had no apparent solid reason for voting them or worse, were influenced by the media they expose themselves to (e.g. a newspaper which backs a certain party).

The flip side to this is how much would it actually change the result? probably very little when it comes to the large parties like Labour or the Conservatives due to sheer numbers, but I think the smaller parties with very valid policies would be the ones who lose out. I think a parliament with at least a sprinkling representation from a wide range of parties at least helps get multiple voices heard and means legislations are theoretically subjected to heavier debates before being passed rather than just passed by the majority party as an inconvenient formality.

So how would I define ‘informed’? Of course, to draw a simple line between the ‘informed’ and the uninformed would be very difficult as politics is almost a limitless topic in terms of knowledge and how deep you would want to go. At what point do you say ‘I know enough to make a fair, informed vote?’. Unfortunately, for many I fear it is simply when they hear what they wanted to hear and then it’s case closed. 

Don’t get me wrong, you don’t need to know everything about politics, I don’t, though I think at least enough to know where the major 4 or so stand on the key topics before seriously considering to help change the way the whole country is run. Maybe that is what I would consider being ‘informed’.

I wouldn’t really have a solution to this, the best thing I could think of would be a very basic general test you have to take when you register to vote. Though putting the practicality issues of rolling this out aside, it is bordering the ridiculous in this day and age of democracy and free speech. My opinion is that it wouldn’t limit free speech or be a censoring of opinions, if anything, it would provoke people to take an interest and weed out those who lazily don’t want to educate themselves in such an important matter. 

You could argue that any reason is a good reason and that if you have the right to vote, you have the right for it to be for whatever reason. I obviously don’t agree with that though (the whole point in this post).

For me, I think i’ve made my mind up but I am still digging deeper a little more all the time. When that is a fact, then my mind can be changed right up until I put my mark on the ballot paper.

The bottom line is the decision made by the public through the voting system affects the lives of everyone involved and even if yours isn’t affected for the worse or much at all, someone else’s is likely to be. If your voting without knowing what’s out there or for a comical or trivial reason, you might just be voting a party in that will damage the lifestyles of others unfairly and ultimately, whether you realised the consequence or not, ‘because you could’.

[lawrenciumbc]

Showtime semi-final #mklman come on Phoenix! #eplplayoffs #patp15

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Toon vs Gooners almost ready to go! (at St.James Stadium)

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Awesome stuff tonight in Manchester from 36 Crazyfists!

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Scholes and McManaman doing bt sport at Old Trafford today.

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Yes! In Flames, Ritz, Manchester, awesome time! #inflames @InFlames_SWE (at The Ritz)

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Thought I'd just watch the football tonight #bpl

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Today, i walked a gorge down there #imbros #crete (at Imbros Gorge)

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Cheap Greek night combo! #greece #crete #baklava (at Rethymnon, Kreta)

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So my new toy came today! #sigma #dslr #canon