I am trying to set my Ridgeback road bike up for night riding so that I can enjoy it on the commute during the autumn and winter. The last thing that is stopping me is the interference between my Ixon IQ front light and the wireless computer. I do like to (obsessively) record my mileage but the light and the computer are necessarily much closer on this bike than my flat barred commuting bike. I don't want to spend much money. Anyone know if I can stop the interference by using some form of shielding on the light - e.g. tinfoil?
CityCyclingEdinburgh Forum » Questions/Support/Help
RF interference
(38 posts)- Started 12 years ago by amir
- Latest reply from Instography
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Posted 12 years ago #
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That's a tricky one amir.
Your are on the right track to suggest tackling the source but whether screening will work depends on the frequencies the lamp generates and which frequency your computer needs to be clear.
Assuming the battery is in the lamp housing (so there is no cable to screen) it's well worth experimenting with foil, starting with a complete wrap (worry about getting light out later!).
Do you know what frequency the computer uses? It's often marked on the transmitting end or is in the manual.
The real solution would be to suppress the noise at source, but you'd have to be prepared for surgery to do that....
Posted 12 years ago # -
I think all computers use a 3.2GHz standard wireless frequency?
Posted 12 years ago # -
"The real solution would be to suppress the noise at source, but you'd have to be prepared for surgery to do that.... "
It's not me!!
Thanks alibali - I'll look into the frequencies. The other option would be to move them apart, either by a space saving bar or a crown mount for the light but neiether are as convenient (or cheap) as the current set up.
Posted 12 years ago # -
By the by, I remember stopping at a cash machine on a ride once, then getting back to where we were staying and finding my max speed had been 500mph...
Posted 12 years ago # -
Amir - if you want to investigate use of a space saving bar, I have one that I have never used and no longer need, you'd be welcome to take a long-term loan of it.
Posted 12 years ago # -
Thanks kaputnik, much appreciated. I'll have a go with some foil tonight in Blue Peter fashion and report back. If it doesn't work are you planning to go to PY on Friday?
Posted 12 years ago # -
are you planning to go to PY on Friday
Yep, just let me know and I'll bring it along.
Posted 12 years ago # -
I didn't know LEDs created electromagnetic interference. I know a spark does and a current through a wire etc. but what's causing it in a diode?
Posted 12 years ago # -
I assume it is the part of the circuit that times the pulse, as it has to have some sort of frequency to it.
Posted 12 years ago # -
Whilst some modern lights' improved runtimes are achieved through flickering them on and off quickly, imperceptibly to the non-epileptic eye but easily visible by waving them around quickly in front of a camera doing a long exposure, that would only be in the order of hundreds of Hertz, though it could still be irritating the computer.
Posted 12 years ago # -
My CREE based torch, which I used to supplement the Ixon on dark roads/paths, can trip up the computer from even further away. I think it is the circuit but I am definitely outwith my area of expertise (as always)
Posted 12 years ago # -
I've got a spare computer with wire - Cat Eye 8 I think - if you want it.
Posted 12 years ago # -
As Wingpig says it's the inducer in many of the circuits that causes the problem even running in solid mode it will still be running at many hertz to change the voltage from the battery voltage to the led's voltage.
I'm not sure but a 3aaa battery light should be ok since these are generally "direct drive" and use very simple tech to regulate the power from the battery to the led, though all bets are off if you put it in flashing mode.
Posted 12 years ago # -
Thanks JP. Will let you know.
Posted 12 years ago # -
BTW I don't think that I could have got such intelligent or generous responses on other cycling forum!
Posted 12 years ago # -
"
BTW I don't think that I could have got such intelligent or generous responses on other cycling forum!
"Don't think it's just cycling forums either.
Rules here are simple
RULES No personal insults. No swearing.
Seems to be enough to have attracted a wide range of (intelligent and generous) people who ride bikes for sensible and fun reasons - ie getting around, seeing things and even taking part in some endurance activities!
It started with emails to my contacts and anth's CityCycling mailing list and built with people logging on, seeing how it works - politely, usefully and randomly - and then joining in.
Posted 12 years ago # -
chdot thanks to you and ant, on almost the second anniversary
Posted 12 years ago # -
Good news (in voice of the professor in Futurama - currently being repeated on pick tv). Aluminium foil works! The lamp looks really ugly but the foil does seem to shield the emanations
Posted 12 years ago # -
could you open it and tape the inside of the case?
http://www.ebay.co.uk/sch/i.html?_from=R40&_npmv=3&_trksid=m570.l2736&_nkw=aluminium+tape
Posted 12 years ago # -
I utterly love the fact you've given your bike a tinfoil hat.
Any day now it'll be talking about the flag waving on the Moon landings...
I was talking to the lady that inexplicably still associates with me about how civilised this forum is. I reckon, cynical old trout that I am, that it stems in part from the fact that everyone knows that the person you're considering insulting only lives a handful of minutes away and will, quite legally, be carrying a great big swingable chunk of metal when he/she arrives.
"You call fixed gear a hipster fad again and..."
"Blah blah blah. You'll be telling me you rode fixed before it became cool"
"RIGHT! That's it!"
"What you gonna do, ride over here?"
"Yes. It'll take me about eight minutes."
"Would only take you five and half riding geared."
*cartoon punchup sound effects*
Posted 12 years ago # -
Ha! I take it the "a great big swingable chunk of metal" is the bike. I'm not sure with my puny upper body strength I could wield a bike as a weapon. But Bicycleworks did once try using my bike as a tool by clamping a seized crank in a vice and trying to turn the bike. It didn't work.
Posted 12 years ago # -
Newps, I meant the D lock or chain, although anyone who has take the time to invent and then learn the art of bike-fu has plainly gone brainwrong to the point of danger.
I'd pay money to see someone twirling a Brompton about like a pair of nunchucks, mind.
Posted 12 years ago # -
In Russia Brompton folds you.
Posted 12 years ago # -
"Aluminium foil works!"
That is good news, so the question now is how to make a practical screen that lets the light out and offers access to switches and batteries etc.
I thing aesthetically pleasing might be out of reach..
Probably the simplest route would be sticky aluminium or copper tape, as mentioned by custard. This is available for exactly this application and you can probably get some at Maplin, but the 2" tape on custard's link looks OK.
Alternatively, a metal box to put the light in would work. Maybe a shortbread tin, for example with a hole for the light.
I guess higher output LED lamps probably use some kind of switch-mode regulator to convert the battery voltage to a current suitable for the LED(s) with the switching for battery saving mentioned by wingpig and steveo on top of that. Nowadays these switchers usually operate in the 100kHz (long wave) to 1MHz (medium wave) band (to keep the inductor steveo mentioned small and cheap) but with fast switching (for efficiency) can generate really broad band interference.
Which is a long-winded way of saying you can probably gauge how well your screen works by placing an AM radio close to your lamp and tuning it for maximum noise. Then see if your screen reduces the noise...
Posted 12 years ago # -
would metallic spray paint work?
Posted 12 years ago # -
As Wingpig says it's the inducer in many of the circuits that causes the problem even running in solid mode it will still be running at many hertz to change the voltage from the battery voltage to the led's voltage.
You can see this effect on modern LED traffic lights, and particularly when the red man on the pedestrian control box is illuminated. Flick your gaze quickly left and right and you can see a line of discreet red men as the LEDs flash on and off.
would metallic spray paint work?
Conductive paint with a foil-backed cover plate is often what luthiers use to shield a guitar's control cavity from RF. Others prefer to line the cavity with very thin copper sheet, soldered at all the joins.
Posted 12 years ago # -
would metallic spray paint work?
Worth pointing out a detail here. As Arellcat says, conductive paint will work but metallic paint is not usually conductive.
Conductive paint is usually quite expensive as it has enough metallic (often silver) content for all the bits to touch a neighbour. Metallic paint just has to look nice.
Posted 12 years ago # -
perhaps you could disassemblate the light and get the foil on the inside? although then you have to be careful that the foil doesn't touch any of the internal electronic witchcraftery and cause a short.
Posted 12 years ago # -
The battery hatch is hinged. The serious electronics is well in front of this and cannot easily be accessed. I'd be relunctant to hack the light apart. Besides the silver foil gaffer-taped to the light adds a bit more personality to my ride.
BTW - one layer of aluminium foil doesn't work - you need several.
Posted 12 years ago #
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