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Re: Shielding a QL, issues and questions.

Posted: Thu Oct 27, 2011 5:15 pm
by dilwyn
Mr_Navigator wrote:
That's a great story, did it drive ok?
Yes it did, however because of the size of the track, It couldn't go very fast without spinning off, the car was just too fast and also there are only so many laps you can complete on your own without any other competition to maintain the interest :( (I think it was more about building it than playing it which is why I think I went it to engineering when I left school). Eventually I moved on to other engineering things like the cellar with all the electrics for the house coming together on one board and some paint. But that's another story. :)

I just did a quick look around to see if I could find the orange racing car I bought, and here it is worth £45 now apparently.

I go on thinking that this might be an interesting project. A Scalextric circuit where one car was controlled by the QL, to which you race against. Some A/D needed I suppose, or has this already been done I wonder, anyone?
My brother and I had a scalextric set when we were school age, but it always had the problems that the cars never went at the same speed so it was a bit unfair - the orange car was always slower than the blue car. We did acquire a third car from a scrapped set, but it never worked on our system (probably was broken, that's why the set was scrapped!). I remember we got fed of the inequality eventually and took it all to bits to see if we could find out why. Needless to say, it never worked properly after that and we eventually got a set called TCR (Total Control Racing?) the following Christmas to replace it.

The only thing the Scalextric achieved for us was that we both took an interest in electrics and electronics after that and I went on to build some daft projects like a Rain Detector - a piece of Veroboard clipped to a washing line outside and a little circuit testing the continuity which made an awful racket through its little speaker. AFter a while, my little brother realised that if he shot the detector board with a water pistol, it made mum panic thinking it was raining, then after a while she refused to use it as "it was faulty". It was years later that my brother admitted what he'd been doing to it.

AFAIK human vs QL scalextric has never been done, although I'm sure that someone like David Buckley in Quanta with his experience of QL robotics etc would know how best to approach this!

Dilwyn

Re: Shielding a QL, issues and questions.

Posted: Thu Oct 27, 2011 8:52 pm
by Dave
How would I contact this David Buckley?

I am working on a fairly extensive D2A board, plus a home automation "thing" which can take inputs from indoor and outdoor thermostats to smartly control the AC (knowing when to run it, when to instead use outside air, and when to run the AC as a dehumidifier, etc)

Re: Shielding a QL, issues and questions.

Posted: Fri Oct 28, 2011 12:23 pm
by Mr_Navigator
How would I contact this David Buckley?
He is the QUANTA librarian, the contact details are on the website I think

http://www.quanta.org.uk/about-quanta/c ... librarian/

Re: Shielding a QL, issues and questions.

Posted: Fri Oct 28, 2011 8:49 pm
by vanpeebles
Could I use the ground pin from the psu socket or would there be some kind of dimension opening explosion? :shock:

Re: Shielding a QL, issues and questions.

Posted: Sat Nov 05, 2011 10:33 pm
by vanpeebles
A worrying lack of answers! I got a spare bottom (oo-er) to setup with the copper shielding:

Image

Re: Shielding a QL, issues and questions.

Posted: Sat Nov 05, 2011 11:59 pm
by Mr_Navigator
that is very wide copper strip :)

Re: Shielding a QL, issues and questions.

Posted: Sun Nov 06, 2011 3:39 pm
by Dave
I'll just throw in that if the through-wires on the bottom of your PCB touch that strip, it's likely game over for that PCB.

I have always preferred zinc-based paints.

Re: Shielding a QL, issues and questions.

Posted: Sun Nov 06, 2011 4:02 pm
by vanpeebles
Yeah I'll have to watch the clearances and maybe do a clear coat. Although I think there is a big enough gap between the bottom of the case and the supports that the board sits on.

Actually I have some car spray primer that is zinc based, could be worth a try.

Re: Shielding a QL, issues and questions.

Posted: Sun Nov 06, 2011 6:55 pm
by tofro
Hi all,
Just some random thoughts and remembered bits from long-forgotten university lectures:
  • Electro-Magnetic waves have an annoying tendency to leak through shielding like water (Basically, the waves are reflected in the inside of your shielding until they find some way out), so your copper plating should be as "water tight" as possible. I would recommend to add some foil to the side of the case as well.
  • I I think would connect the foil to somewhere at the TV modulator. This is heavily shielded already, so you can't do wrong connecting the foil to the modulator's outer housing. Maybe you can use some sort of spring that connects the copper foil to the modulator housing when the case is closed?
  • In my Samsung QLs, the D-Sub connector ground is also connected with the inside plating (I think there's not much metal to the UK connectors?
  • Don't forget to connect the metal keyboard base plate as well. This should cover anything that wants to leave "upwards"
Cheers,
tofro

Re: Shielding a QL, issues and questions.

Posted: Sun Nov 06, 2011 7:45 pm
by vanpeebles
Cheers for the info! I suppose to protect the underside of the motherboard I could always use that thin plastic you get on things that you have to cut open and it attacks yours hands.