jgwilliams

Hi All

I recently bought a Niterider Lumina 750 which, on the whole, I'm quite pleased with. However, I've had to move my CatEye cordless computer as the Lumina is obviously outputting some RF interference which stops the computer working if it's too close. I can now use the Lumina on low, medium or high but not flashing. I have other lights, including a dirt cheap Nestling light bought from Amazon, which don't exhibit this behaviour so I was a little disappointed.

I emailed NiteRider about this and received the following response:

'That behavior is to be expected. It all has to do with how hard the LED itself is being driven. Companies like Nestling don't drive their LEDs nearly as hard as we do which is why our lights produce their true advertised lumen ratings.'

I have a strong suspicion that this is tosh but since my background is with software rather than hardware can someone who is more knowledgeable on these things comment?

Thanks

John

2manybikes

What they say is correct. A corded computer may work. It works with my 2400 lumen light, on many different bikes, that have different kinds of computers on them.

Aubergine 

Yes, I see the same behavior with several of my lights and wireless computers. It happens when they are flashing; evidently the flashing mechanism causes some sort of RF pulse that interferes with the computer’s ability to receive signals from the fork sensor.

I have found that my dynamo-powered lights do not cause problems with wireless computers, and Cateye Padrone computers seem to be immune to flashing lights.

angerdan

It's possible the PWM brightness regulation is cause of the interferences.
A light without PWM, less electronics or a metal housing/case could reduce the interferences to you wireless computer.

CliffordK

It sounds like the company knows of the issues.

They likely need better shielding for their electronics, and eventually will be forced by complaints to update their hardware, but not necessarily recall old hardware.

I thought the FCC regulated radio interference of consumer electronics, but perhaps it is limited to licensed radio bands, and not unlicensed bands. Nonetheless, you could test to see if your device interferes with radio or TV.

Does the packaging include FCC certification... or is it a different certification?

Personally, I can't stand flashing headlights, and use them very infrequently.

Have you tried installing the light elsewhere? Moving it above or below the bars? Helmet?

Shimagnolo

If your LED headlight has variable intensity settings, it is probably flashing even though you don't see it.
I did not know my Dinotte 600L was using pulse width modulation for the lower settings until the first time I rode at night in snow.
On the 25% and 50% settings it generates a really cool strobe effect with the trails of the snowflakes alternately appearing/disappearing.

rifraf

I've read of some computers being affected by dynamo hubs too.

pdlamb

Time for the tinfoil brigade to make an appearance...


Have you considered wrapping the light in aluminum foil? That might provide enough shielding to keep your computer working.

Shimagnolo

Blocking the air flow from a high-power LED light is an invitation for failure due to overheating.

BarryVee

My Planet Bike Blaze two watt LED headlamp & Bontrager Node 2.1 bike computer did not play well together. The computer froze every ride with the light on. Moving them farther apart did not solve anything, different lights did.

I moved on to a Bontrager ION 700 and later obtained a Cateye Volt 1200. Individually or in combination, these plus a Design Shine 500 lumen taillight caused no problems for the Node at all.

This month I added Stages power & replaced the Node with an Elemnt Bolt. So far I've rode 399 miles with these during daylight. All with the ION 700 on hi-intensity strobe & the DS500 on either EMS flash or at a lower intensity for overcast days. My expectations are met. It all works well.

fietsbob

winter sun coming in the window behind this one around noon, is a problem.

steelbikeguy

well, the circuitry is obviously the problem, and it does vary with the amount of current flowing. However, it is very much possible to design the circuitry so that it doesn't emit as much RF noise. I've spent many years at work getting my own circuits to pass the relevant regulations and a few more years helping others fix their problems of this sort.

The regulations in the US are relatively loose for consumer products. The EU, though, tends to be a bit more strict.

Did you have any particular questions about the interference problem?


Steve in Peoria

veganbikes

You certainly wouldn't want to flash a white light in someone's eyes so they cannot see, that doesn't work well. Red lights are fine on the human eyes especially at night and don't ruin our night vision but white light isn't.

As long as the light is working as a solid light I wouldn't worry. Certainly if you are having issues you could get a wired computer which is going to generally be more reliable everywhere anyway. Wireless is great for looks but a wired computer is great for reliability as it is not effected by anything.

jgwilliams

A lot of responses - thank you all for your thoughts.

I used to have a corded computer on this bike but it failed a little while back. It's actually getting quite hard to decent ones here and I didn't really want to get a cordless one as they are less reliable and more expensive. On the other hand I like CatEye computers, having used them for years and didn't really want to get a different make. I have a Sigma computer on my Brompton and it really annoys me. I might have a change around as I have a bike I want to sell that currently has a CatEye corded computer on it.

CliffordK: The light appears to made from metal so I was suprised that this didn't appear to offer enough shielding. I can't see any FCC certification on the packaging. Yes, I tried moving the light around. Currently the light and computer are about as far apart as I can make them without putting the light on my helmet - which I don't really want to do. I like to use a flashing light for daylight riding.

Steelbikeguy: I'm not sure that there's anything much I want to do. If I was a bit more knowledgeable I might ask how I could modify the circuit to reduce RF interference but I don't think I feel quite up to that. I'm just a bit frustrated. I have an old Lupine Tesla that exhibits the same issue. I replaced it because the battery is dying and things have moved on so far in the last few years that it's cheaper to get a new light of the same power than to replace the battery. I was rather hoping that a new light wouldn't interfere and I can't help feeling that if NiteRider designed the light better there wouldn't be a problem.

Incidentally, I have a Garmin Edge that doesn't seem to have any problem picking up the signal from the sender mounted much further away, which I find a bit odd.

2manybikes

It's a common problem most, if not all lights that are powerful will have this problem. It's nothing new.
Corded bike computers are much more reliable than wireless.
Ii think the aluminum foil goes on your head!

steelbikeguy

It's not a simple matter to modify the circuit to reduce the noise emitted. It takes a fair amount of experience, some very good test equipment, and some time.

Adding a metallic shield or a common mode choke is fairly hit or miss, even when you know what you are doing, despite being much easier than circuit modification. The most reliable modification is usually to increase the distance between the light and its cable and the bike computer.

The best (and most obvious) solution is to replace the offending headlight with something else. It would be good to contact the manufacturer of any light under consideration, and ask them about what they do to prevent their lights from interfering with wireless computers. If they mention that they run EMC (electromagnetic compatibility) tests to measure radiated emissions, that is a good sign. If they simply run tests to see if their lights interfere with a variety of wireless computers, that would also be a good sign. If they give the same sort of nonsense answer that you got.. "all lights do this", then stay away!


Steve in Peoria

pdlamb

It's still possible to find good wired computers. I think Cateye makes at least 2-3 models. You might have to order one if your LBS doesn't carry them.


I finally gave up on a 14-15 year old wired computer last fall. I wish I had known to use dielectric grease on the contacts back then, it might still be working. With the dielectric grease, my other bike's Cateye is still working after 11 years. That's pretty reliable, in my book.

jgwilliams

Yes, my Cateye computers have been pretty reliable. This one quite suddenly just failed - no display, nothing. I tried replacing the battery but something terminal had obviously happened inside. Never had anything like that before - in fact the only other failure I've had was when the nut holding my front brake in place fell off. The next time I wanted to stop the front brake shot off ripping the cable in half as it went!

I think the one that failed was an Enduro 8. Anyhow, got another of those on my recumbent which I'm planning to sell this year so I'll probably have a swap around and put the Sigma computer on the recumbent before it goes.