I have a wireless CatEye Vectra computer for my bikes. Since I got it, it sometimes would not work, no matter what I did. Today I finally realized that when I turned on my handlebar light, the computer stopped. I tested it a bit and discovered that if I moved the light away from the computer, it would start working again.

Unfortunately, I don't have quite enough width on my bars to move the light or computer. I suppose I could move the light somewhere else on the bike, but I'd rather leave it where it is. Would it be possible to shield the computer or light somehow to prevent the interference? Or can anyone suggest a different solution?

Thank you!

Not really any good solutions other than: move the light (may not be a good solution), or use a wired computer. It's an issue with anything that creates a magnetic field, so even a dyno light mounted on the handlebar would cause the same issue. FWIW, you could try to fabricate/use an off-the-shelf crown mount for your light. It may help, it may not.

Thank you. I have searched around and learned that this is an endemic issue, with no realistic solution other than distance between the interfering signals. I think I will be moving my computer mount rather than the light, because I use the computer more for recording mileage than anything else.

Ran into a similar incompatibility here. An STS computer that generally froze with LED bike lights, particularly in flash modes. After enough frustration gave up an got a newer Ant+ computer, a Bontrager Node 2.1. That computer works fine with both a Bontrager ION 700 headlight, a Blaze 2 watt headlight & a Cyglolight Hotshot taillight in any mode. (Am using Hr strap + DuoTrap speed/cadence sensors). Computer is mounted on the stem with a headlight on either side mounted to the bar.

If it's a battery light and you're running it in flash mode, don't do that. Run the light in the brightest mode it's got, so you don't have any current switching going on, which would also generate magnetic fields.

If it's a dyno light, you might want to look into replacing the light wire(s) with coax cables, like the SON wires. The coax might provide enough shielding to let the speedo work.

the switching power supply in the light is creating radio noise on the same frequency that the speedometer transmitter uses. Shielding the speedometer receiver is just going to reduce the signal strength from the transmitter, so if you want to add shielding, it needs to be added to the light.

Adding shielding to the light needs to be done in the right way. It should be done at the circuit itself and connected to the battery negative. However, it needs to be done at the circuit board.
The noise can also be radiated from any wires leaving the circuit board, so a similar shield should be added around these wires.

I do this sort of thing for a living, and it's rarely a simple solution. There are no regulations for this sort of problem, so the manufacturers of lights and bike computers have no guidelines to design to. I'd suggest contacting the light manufacturer and see if they know that their light is causing problems and see if they can suggest a fix. Perhaps they can even swap it for a part that doesn't emit so much noise??

The alternatives have already been discussed.. moving the light away from the bike computer or switching to a wired bike computer... or moving the computer's transmitter closer to the receiver.

drop wireless computer for one with a wire of course..

I have the Sigma 16.12 STS CAD computer and the sensors are on the left side of the unit. Long story short, my light (niterider 550 or 750) is now on the right side of the bars and I have no problems with a previously malfunctioning computer.

Thanks everyone. [MENTION=404644]kingsleadhat[/MENTION], I'll definitely give it a try!