Wireless computer and HID light problem

[sly_artichoke]

OK technogeeks, help me out here. Cateye Adventure wireless computer won't work when my Light and Motion, HID, bar-mounted light adjacent is pumping out the lumens. Obviously some sort of electrical interference between the two, but is there a method of shielding the computer from head unit of the lamp? I've tried a few layers of aluminium foil wrapped around the lamp, to no effect. Lead might work I suppose, if I can find any these days. But then there's the possibility of the lamp overheating.

Any takers?

 

[Spanky_Ham]

The pig is not an electricery pig... however, the "ballast" in HID lights produces an "electrical" noise which can drown out other things.... (ie your wireless bike computer)

Alot of the noise can occur in the power leads to the lamp, acting as a HUGE antennae... so maybe try shielding the power cable???

S

 

[crash bandicoot]

I get the same problem at home with the bike on the trainer. Wireless sigma computer won't work when the halogen down lights are on, but will work at night when using led bike light. Maybe the wavelength ??? colour ??? of the light interfering with wireless transmission.

 

[axiomtheory]

What you might find thats its in the halogen down lights. Like the HID's the down lights need a transformer to bring the voltage down to the 12V DC. That will create the electrical noise which will drown out the signal from the bike computer.

 

[{ScarFace}]

Had the same problem from a few customers at work, I was no help. Keenly awaiting an actual solution.

 

[hmcleay]

I think you're on the right track with the alfoil for shielding.
However, for shielding to work, the shield has to be earthed to something, so that it can dissipate the 'captured' charge somewhere.
Given that it's on a bike, which is very well insulated from the ground by rubber tyres, you can't exactly earth it to the ground.
I don't really know, but you can probably earth it to the -ve terminal of the light battery. however, this could also be difficult if it's a sealed unit.

guitarists have a similar problem with electric guitars picking up 'electrical noise' in noisy environment (fluoro lights do this, among many other items). try googling 'shielding guitar pickups' or similar.

You might get a better response asking the question in this forum:
www.austech.info

Cheers,
Hugh.

 

[axiomtheory]

I think you're on the right track with the alfoil for shielding.
However, for shielding to work, the shield has to be earthed to something, so that it can dissipate the 'captured' charge somewhere.
Given that it's on a bike, which is very well insulated from the ground by rubber tyres, you can't exactly earth it to the ground.
I don't really know, but you can probably earth it to the -ve terminal of the light battery. however, this could also be difficult if it's a sealed unit.

Cheers,
Hugh.

Continuing on with what hugh has said. To complete a shield you would essentially have to make what is known as a faradays cage around the piece of equipment that is creating the noise in this case its the ballast for the HID light. In most HID bike lights however the ballast is in the actually light itself, not in the wiring or the battery. To make a successful shield around the light(or to create a complete faradays cages) You would need to completely enclose the light in shielding(foil). Which unfortunately defeats the purpose of the light.

A real world solution without complicated electronics, you have one of three choices, change to a wired computer, change to LED lighting, or only use one at a time.

 

[frensham]

A real world solution without complicated electronics, you have one of three choices, change to a wired computer, change to LED lighting, or only use one at a time.

Not so quick with the move to LED lighting! My Nitelights (900 lumen LEDs) on FULL power have the same negative effect on my Cateye wireless computer. On lower power, no problem. It's not just Halogen and HiD lights that interfere with wirelss computers.

 

[sprocket]

Not so quick with the move to LED lighting! My Nitelights (900 lumen LEDs) on FULL power have the same negative effect on my Cateye wireless computer. On lower power, no problem. It's not just Halogen and HiD lights that interfere with wirelss computers.

I have the same issue with my LEDs, still need to find a solution for it as i would like to have the high power setting on..

 

[auskonrad]

Do GPS units like a Garmin or a Bryton use a different signal to the basic wireless computers that is unaffected by this interference?

I haven't seen it anywhere, but do Ay Ups cause anything like this?

 

[BLKFOZ]

I also get my LED bar light cutting out the signal to my wireless comp. I mainly use my comp for timing laps and getting total distance for a ride. So I'm thinking about making a mount for the fork leg or up near the crown for the display so it still works, just wont be able to view too well while riding. I find it only needs to be about 6-8 inches under the bar for the interference to stop effecting it, so it should be ok mounting down lower.
Would be good to have a solution to the interference though.

 

[sly_artichoke]

A solution

I'm happy to report that I've found a solution. It's not ideal, but it does work. I asked Light and Motion for a solution, but they're yet to get back to me. Other forum searches web-wide suggested some options, and a combination of two has done the trick.

Spanky_Ham was sort of on the right track with shielding the cable but didn't mention HOW to shield it. And just shielding the cable wasn't enough. I still needed space between the light and the computer.

So, as shown in the images, the solution for my problem lies in separation AND shielding. The distance between the light unit and the computer is around 180mm. Reducing this gap by even 10mm resulted in interference again. This is almost as far apart as I can manage on these bars. Bar width overall is around 700mm. I'll move the computer to the stem for day rides (it only takes a minute or two), as it's a bit more vulnerable out there on a limb.

The widget near the battery is known as a ferrite choke or ferrite bead amongst other names, and suppresses high frequency noise in electronic circuits. I bought a pair from Jaycar Electronics for about $9, but if you've any old computer cables lying around, these are often near the end. What surprised me was that it didn't matter where on the battery lead I put the choke, it still worked. But then I haven't a clue about electronics, so maybe that's obvious to someone who does. And yes, the battery is a tight fit, but it works.

So I hope this helps those of you out there who like to record your stats after dark. And the solution should work for LEDs too. Can't help with the halogen downlight problem though. I can only suggest pulling each light out and putting a choke between each light and its transformer, on the 12V cable.

ps. Response from Light and Motion early this morning was "With the HID Light the most accepted form of getting around this problem is to mount the light on top of your helmet." Sure, that's a solution, but just not the solution I was looking for.