I just got a Night Rider Lumina 700 bar mount LED light for my mountain bike. What an awesome light!! However, when I run it on low and medium settings, it interferes with my Cateye Micro wireless computer that is stem mounted and will not give any speed/distance read out. On high brightness or flash setting, the computer runs normally. I have to move the light about 12 inches away to stop the interference.
I also tried putting my Cygolite MityCross 380 dual beam light next to the Micro wireless computer and it operates normally when the light is on any setting.
Does anyone have a solution besides distance for this behavior? Shielding?

First thing I would do is call Lumina and ask them for help, your issue can't be unique and they may have a solution for you. If they can't help then maybe shielding the cable from the battery to the headlamp will help, also a simple pi filter (inductor/capacitor) on the input to the headlamp can be a solution. If the issue can't be addressed with a power filter you're screwed. In that case, the PWM power converter inside the headlamp is radiating and the PWM needs to be tweeked to make it stop interfering with your computer.

holy crap, I have this exact setup, light and computer models as well as mounting positions. i have experienced issues with my computer during the beginning of my morning (almost always dark) commutes. however, it doesn't happen all the time. I am very interested in following this thread. since I never had an issue with afternoon commutes (light in flash mode), I chalked it up to cooler temp battery issues or moisture in the air connectivity, both having to do with the computer.

(buy a) A wired computer ? Try shielding .. a bit of metal foil tape over the wire grounded to the frame will isolate RFI .

in Music gear a Mic cable shields better than a guitar cable , because the signal is the 2 +- wires inside the braided shield

the other the shield is also the - return wire of the circuit.

the OP says the computer is not wired. the 1st reply mentions shielding the wire for the light, but that light is also wireless. it uses USB charging technology.

Wireless computer being used....The easiest way to fix this is to use a "wired computer". The other option is to move the lights as far away from the computer as possible.

Although it's never been talked about ( as far as I know ) I've wondered if the same thing happens with devices using either Blue tooth or ANT+. For me that's an important question to answer because I've considered the possibility of using a wireless speed sensor ( BT ) to use with a smart phone app.

I've ridden thousands of hours at night using various 18650 powered flashlights, a couple generations of Magicshine headlights, and more recently a Gemini headlight, combined with a couple older generation Cateye wireless computers (when their only wireless computer was simply called Cordless), then a Strada wireless, and most recently the current model of Micro wireless:

CC-MC200W | CATEYE

I've never had a conflict between the lights and computers.

I suspect the OP's headlight is the source of trouble based on my limited experience of light+wireless computer combinations. I cannot offer a novel solution; move it far away (fork leg?) or simply replace it.

The NR Lumina is an all-in-one light. No cable.
How about a flux capacitor, Marty?!

The Wireless will also show you are moving at some stop lights...like 75 mph.

They function properly with 18650 battery lights.

I suppose, since I bought it at Performance, I could exchange it for a wired unit since they'll stand behind all products for whatever reason, but I'd rather not do that. I've got enough wires on this bike and I just thought wireless would be cleaner amongst all the other cables, etc. If I find a solution, I'll post here.

The Cure is to use 18650 powered lights.

https://www.fasttech.com/products/1601/10000911/1591001

https://www.amazon.com/gp/product/B00..._email_1p_0_ti

ANT+ and BT are basically immune to interference from lights. What the OP is seeing is basically standard for LED lights and non-digital wireless computers.

Most LED lights have 2 settings, ON or OFF. High = ON continuously. Flash is usually a long burst (~100 ms) at full power. To achieve settings other than OFF or HIGH, the manufacturers rapidly pulse the light at ~kHz frequencies. If the light isn't well-shielded (most-aren't since shielding is expensive and heavy), the light puts out a bunch of RF noise at the pulse frequency.

The battery type used by the light has absolutely no impact on if it generates interference or not. Some lights do, some don't. It all depends on the internal control circuitry. More powerful lights will be more likely simply due to the higher current draw and therefore larger RF spikes.


The stupid wireless computer basically just looks for a short pulse at a given RF frequency (also frequently ~kHz). The noise from the light can totally swamp the receiver on the computer.

As a general rule, I consider non-digital wireless computers not worth the money. Either get a cheap wired or move up to Garmin (or equivalent).

Thanks for the info on the BT / ANT situation. The rest of what you wrote I couldn't of said better myself.

At the OP; One of the two has to go, either the lamp or the computer. If you're dead set on keeping the Cateye wireless computer than it has to be the light. My advise; go to a store with a good return policy...buy another self-contained lamp. I would suggest something like the Cygolite ExpiliON 680. This lamp has been very well rated and has the added feature of being able to replace the battery when needed. Also consider the Cateye Volt; self-contained two emitter set-up. Since it's made by Cateye who also makes wireless computers perhaps it is better shielded against RF interference. REI sells both of these products and has an excellent return policy. Whatever doesn't work just take back.

This is why a gave away my old wireless computers (had Cateye and Planet Bike). I converted to Garmin because I can use the same computer on all of my bikes. Moving to Garmin was well worth the investment, I can't image going back to the Cateye.

I'm interested to find out if you get a solution, my wife still rides with the wireless Cateye computers (doesn't ride roads as much as I do) and I want to get her the Lumina700 - the NiteRider Lumina700 is a GREAT LIGHT!

I have the same NR Lumina 700 light and HAD a old Cateye Dual wireless computer on the same bike. Had he same interference issue on low and medium, and on flash it was inconsistent with occasional interference. I also had interference from other things on parts of my ride. On thing that seemed to cause interference was the newer electric street cars/trains in SF (whenever one was going by my computer would stop working).

I eventually got sick of it and got a newer ANT+ computer and sensor. No problems with that or with the BT sensors on my other bike. I think if you are going to go wireless its worth either doing BT or ANT+.

How does this solve the problem?

[MENTION=341677]gsa103[/MENTION], excellent explanations!

Thanks for the replies and ideas. Since I don't log many mtn bike miles at night, it's not really a big issue. When I do go out and hammer a night ride and I want to see my performance, I'll just keep the light on hi since it lasts 1:30 and I usually don't stay out that long. Like I said, the NR Lumina 700 is a badass light and I got it for ~$85 at Bike Tires Direct on a special so I'm not about to send it back.