Yet Another Cycling Forum

General Category => On The Road => Topic started by: ABlipInContinuity on 03 September, 2008, 12:39:21 pm

Title: electro magnetic pulse powered by a dynamo?
Post by: ABlipInContinuity on 03 September, 2008, 12:39:21 pm
A quick bit of reading shows that that a dynamo would not generate the kind of energy required but it's a nice thought.

Would be great to cause the spontaneously disable any vehicle driven in a twuntish manner.

Title: Re: electro magnetic pulse powered by a dynamo?
Post by: David Martin on 03 September, 2008, 12:43:12 pm
A quick bit of reading shows that that a dynamo would not generate the kind of energy required but it's a nice thought.

Would be great to cause the spontaneously disable any vehicle driven in a twuntish manner.



Dynamo and a gert big capacitor. Say goodbye to you r PC, mobile phone, MP3 player, bike computer, and camera.

..d
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: Jacomus on 03 September, 2008, 12:44:29 pm
It would be fantastic.

Sensor to detect the speed differential of the passing car, and the distance from the cyclist. Too close and too fast = EM Pulse.
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: Greenbank on 03 September, 2008, 12:45:34 pm
So a dynamo is ruled out, but that doesn't stop you making something that could be charged up at home from the mains.

That aside, what do two wrongs make?
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: ABlipInContinuity on 03 September, 2008, 12:51:02 pm
<snip>

That aside, what do two wrongs make?

Granted, this thread belongs in fantasy land!
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: border-rider on 03 September, 2008, 12:53:29 pm
Hard to do given that most cars are pretty-good Faraday cages.

You might be able to get some temporary interference with engine management, doorlocks, sunroofs etc but I seriously doubt you'd do any damage  - or have any real effect.

Cars tend to be tested against things like radar pulses, for obvious reasons, and only freaky-weird stuff like Fylingdales causes problems these days

Having said that, one of my colleagues had a Fiat Uno in the late 80s - one of the early really common cars to have sophisticated engine management.  That refused point blank to do anything at all on a BBC World Service site - we had to push it 100 m down the drive.  But then, the one we had often did that anyway ;)

Carbon/glass fibre panelled vehicles might well be more susceptible.  But i reckon something like a Taser, that injects pulsed current direct into the structure, could be far more effective at disabling a vehicle.
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: andygates on 03 September, 2008, 12:59:33 pm
I believe Charlotte and I are in agreement about the deployment of the Mark I Vehicle Disabler: take the key out.   :demon:
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: Jacomus on 03 September, 2008, 01:09:40 pm
I believe Charlotte and I are in agreement about the deployment of the Mark I Vehicle Disabler: take the key out.   :demon:

That wouldn't work on a pratmobile as it passes you at 60mph on a B-road, an inch from your handlebars.

Title: Re: electro magnetic pulse powered by a dynamo?
Post by: clarion on 03 September, 2008, 01:10:35 pm
But carrying Fylingdales' array on your pannier rack doesn't work either :(
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: iddu on 03 September, 2008, 01:20:18 pm
I believe Charlotte and I are in agreement about the deployment of the Mark I Vehicle Disabler: take the key out.   :demon:

That wouldn't work on a pratmobile as it passes you at 60mph on a B-road, an inch from your handlebars.


I've a hankering to mount a paintball gun, to wing 'em with a (sticky) dayglo colour first, and then hunt them down... :)
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: andygates on 03 September, 2008, 01:21:15 pm
Pungee spikes.   :thumbsup:
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: tiermat on 03 September, 2008, 01:45:18 pm
Having said that, one of my colleagues had a Fiat Uno in the late 80s - one of the early really common cars to have sophisticated engine management.  That refused point blank to do anything at all on a BBC World Service site - we had to push it 100 m down the drive.  But then, the one we had often did that anyway ;)

As I think has been discussed before herein, Renault Meganes of the late 90's and early 00's had an issue with the immobiliser, if you parked the car too near a police/ambulance transceiver tower you wouldn't be able to get the car going again without pushing it out of range.  We found this out from an AA man one day after a party when we went to recover our car and it wouldn't start.  Said AA man told us about the issue, and that it also affected Subaru Imprezas of that vintage.  Guess which model of car the North Yorks police had just bought 7 of? :)
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: border-rider on 03 September, 2008, 01:54:45 pm
My business partner has a Lexus (in gold, referred to behind her back as The Pimpmobile :)) and she sometimes comes back to it to find the windows down and the sunroof open.  That seems to be emergency services TETRA, as far as we can tell.  The Lexus has a button on the keyfob that does this automatically, and a lot of car remote keys operate at similar radio frequencies to TETRA. 
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: clarion on 03 September, 2008, 01:56:16 pm
I never had such a problem with my last car - but then, it was a Mini, and the sunroof & windows weren't even electric, let alone remote. :D
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: David Martin on 03 September, 2008, 02:04:29 pm
I believe Charlotte and I are in agreement about the deployment of the Mark I Vehicle Disabler: take the key out.   :demon:

That wouldn't work on a pratmobile as it passes you at 60mph on a B-road, an inch from your handlebars.



<spike bike>
It does if you remove the key with an RPG
</spike bike>
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: andygates on 03 September, 2008, 03:00:49 pm
Shoulder-mounted, recoilless.   Perfick.
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: TimO on 03 September, 2008, 05:31:25 pm
Not a chance in hell of powering one with a dynamo, at least for something that would do more than create a slightly annoying noise on a cell phone conversation.

Some of the designs for directed energy weapons which I've seen in the past used a rocket engine firing through a magnetohydrodynamics (MHD) system to generate enough energy.  They also tend to have capacitor banks in the back of trucks and so forth.  They are generally not man portable, although I suspect most of these sort of systems were intended to work over greater range than say a cyclist might want to use against a car engine.

Any system which could be built by an amateur is likely to be too heavy, and too power hungry to be made portable.
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: andygates on 03 September, 2008, 06:25:57 pm
How about one of these?


Northrop in electric blaster cannon milestone | The Register     (http://www.theregister.co.uk/2008/09/03/northrop_jhpssl_two_chain/)
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: Regulator on 03 September, 2008, 06:27:39 pm
How about one of these?


Northrop in electric blaster cannon milestone | The Register     (http://www.theregister.co.uk/2008/09/03/northrop_jhpssl_two_chain/)


I think you might have to borrow Gerald's cargo bike for one of those...  ;D
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: Zoidburg on 03 September, 2008, 06:31:53 pm
They had problems in Longeaton when the police switched over to the new secure radios

They work by using a roving frequency dictated by algorythym

Which also activated all the car imobilisers in the car park at Asda next to the police stations big diapole antenna
Title: Re: electro magnetic pulse powered by a dynamo?
Post by: border-rider on 03 September, 2008, 06:36:58 pm
TETRA again

If you had to design an interference source, that would be it. 

We did some work for the Dept of Health making pretend TETRA radios for human volunteer tests looking for health effects.  Supposed to be double-blind trials but as soon as you fired one up in transmit mode, all the monitors in the room flickered and the computer speakers rumbled.  One group were trying to do ECG measurements, and we had to build a fancy optical fibre gating control system to kill the transmit briefly and grab the ECG.