Radio and RF

Cateye Micro Wireless Bike Computer interference

LED lights causing RF interference with Cateye Micro Wireless Bike Computer stopping the speed sensor from working

Cateye wireless bike computer

We recently purchased a pair of Specialized Crux E5 cyclocross bikes from Primera Sports in Bournemouth which we plan to use for longer road rides and some off road and keep our full suspension mountain bikes for just off road rides.

We purchased Cateye Micro Wireless bike computers (model CC-MC200W) to use on the bikes as they are a nice and compact computer and have enough functionality for our needs to keep track of speed and the distance of the rides.

The new computers seemed to be working without any problems until we came to switch on our LED Moon NOVA 80 lights and then the signal from the bike computers sender unit stopped reaching the Cateye computer and the display showed that no signal was being received. Turning off the LED lights restored the signal so there was a problem with the LED lights transmitting on a frequency close to or a harmonic of the wireless signal coming from the Cateye wheel sender unit which blocked the bike computer from receiving the senders signal.

When we returned home we experimented with different locations of the LED lights and also the bike computer and the computer would work with the LED lights running but only if the light and the computer was separated by over one meter. As this wasn’t possible on the handlebars we removed the computers and ordered a different brand of wired computer which runs without any problems regardless of the LED lights fitted on the handlebars.

In order to try to resolve these problem and find which frequencies are being used, we wrapped a wire around the sender on the bike computer to act as antenna and connected this to our scope. When passing the magnet past the sender unit a pulse was being generated at 19.16 kHz with a time period of approx. 3.4 microseconds.

The scope screen shot below shows the pulse from the scope.

Click to view large image of 3.3ms pulse on scope

The scope screen shot below shows the pulse showing the frequency and waveform.

Click to view large image of 19 kHz pulse from sender

We then wrapped a length of wire around the Moon Nova 80 LED headlight to capture the RF being emitted by the light and when connected to our spectrum analyser there was a general increase in RF noise between 0Hz and 10Mhz.

Connecting this to the scope showed several different spot frequencies being generated with a strong pulsing signal at 7.8kHz as shown on the screen shot below.

Click to view large image of LED Headlight RF generated

We then tried our more powerful SolarStorm LED headlights with have two CREE led units and found that the power cable was radiating a signal with a large primary pulse and a smaller secondary pulse at 49.3 KHz. This signal was only present when the LED light was on its medium or high setting but not on its lowest power mode. The screen shot below shows the RF being generated by the SolarStorm headlights.

Click to view large image of Solarstorm X2 RF generated

In order to test if it was a spot frequency or wideband noise causing the Cateye computers to fail we used our frequency generator with signals from 1 kHz to 100 kHz into an antenna near the bike computer but this didn’t stop the senders signal from reaching the bike computer. The signals being generated and leaked by the LED lights was not a “clean” signal and had a lot of harmonics and this must be causing the interference problems with the Cateye computers.

After searching for this problem online there are a lot of other posts on cycling forums relating to the Cateye wireless computers and LED lights. We don’t have any other brands of wireless bike computers to test so we don’t know if this a Cateye only problem.



18 November 2018 at 1:08 pm
Could wrapping silver foil around either light or computer have stopped this interference?
19 November 2018 at 10:32 am
Adding foil around the bike computer would have shielded it from its own transmitter sensor so it wouldnt work. The lights did already have shielding but the RF was still getting out.
04 January 2019 at 11:46 am
Have the same no signal issue with my Sigma ROX8.0 or 1606L wireless cycle computers and any of my LED bike light. Nice write-up and testing, long time since I've done anything like that, even for fun. Glad to say no such issues when using my Garmin GPS/cycle computers.
14 June 2019 at 5:26 pm
just replaced 2 Cateye wireless computers because of erratic readings. Turns out handlebar mounted iphone used for music was interfering with Cateye. Removed mobile phone, Cateye now reads correctly
07 July 2019 at 9:26 pm
Greg and anyone else. Have this EXACT problem with CAT EYE PADRONE wireless and Samsung Galaxy Note 8 right next to it on handlebars. When streaming music, cat eye reads erratic and miles at end are off by sometimes 6 miles and speed stops sometimes during ride. Has ANYONE come up with a solution other than 1) remove phone 2) Get a smaller wired computer? thanks
18 July 2019 at 11:10 pm
I have experienced this tonight with a Moon Meteor-X Pro front light and a Giant Axact 9w wireless cycle computer. Am thinking of wrapping the light in kitchen foil...
17 August 2019 at 12:33 pm
I had the same problem with my Android phone and Cateye wireless computer. Putting the phone in Airplane mode seems to have solved the interference problem and has the added benefit that I'm not bothered by calls and texts during the ride.
25 May 2020 at 8:58 pm
I have a Cateye Padrone
Everything worked fine 2018, 2019 - starting this year 2020 - the speed was randomly erratic (55-60mph when standing still or while riding) - Turned off LED lights (Cateye HL-EL135) as per what web and Caateye said was the likely cause.
Did NOT fix issue -
Moved iPhone 7 from handlebar to jersey back pocket and computer functioned fine again.
No clue why this started malfunctioning this year due to iPhone interference (iOS upgrade?)

07 July 2020 at 9:30 pm
Has anyone had a problem with the Cateye Padrone CC-PA100W and using a bluetooth bose speaker? If so, what is your work around? Thanks in advance and it's incredibly frustrating that no-one at the bike shop mentioned that might bluetooth speaker might cause a problem...
03 August 2020 at 9:30 pm
I've also been struggling with this. My Cateye Padrone (non-digital) documentation lists 19Khz as the transmitter frequency, just as indicated above. This is a very low frequency (relatively speaking) so a radio frequency choke will not help. I am using BrightEyes light. I found that moving the battery to the frame of the bike, (about 25 inches away from the computer) stops the interference. I also found that running the light at maximum brightness reduces the interference: modern dimmers operate by interrupting the current thousands of times each second so they radiate maximum noise at low duty cycles. At maximum brightness there is less dimming and less radiation.

The wireless padrone operates on bluetooth, 2.4 GHz so it is less prone to interference from headlamps but more prone to interference from smartphones! You can't win.
Nayme Mi
20 August 2020 at 10:17 am
You can use wires, that's how you win. Look at any serious piece of engineering - wires are used, or the wireless used is beefy as hell. Not like this cheaply-engineered, badly-shielded LED emitting poo... Yes, it's not as cool, but until the idiots running the radio spectrum show can get it together to not cram everything on 2.4GHz and require EMI to be lower or devices to be banned, then here we are.
24 November 2020 at 3:46 am
When replacing my Padrone sensor I ran into the same problem with interference in my workshop... I thought it was a bad sensor but when I moved the bike out of the workshop the Cateye Padrone functioned fine using the "Speed Sensor A" 169-6580 Cateye part.
08 May 2021 at 12:04 pm
I have the similar problem with my Cateye Padrone when streaming LIVE radio with my Samsung S10 on my Stem of my handlebars and my Padrone with the front arm mount. The min I stop the music, the speedometer works, hit play... it stops, etc. I had to put my Padrone up high on my aero bars for the Padrone not get interference from my S10 cell.
19 June 2021 at 6:11 am
FWIW: Just was able to fix a longstanding problem with my wireless Cateye Padrone. Same as everyone above, speed sensor stopped working with my Cateye Volt 1700 on flashing mode. I wrapped the Volt with a few layers of Speed Tape (Aluminum tape, actual aluminum foil with a impressively strong adhesive) used on commercial airliners, you can find cheap versions at most dollar stores. Long story short, it works. Aluminum is pretty good at transferring heat, so I’m not expecting that to be an issue. Been a Cateye fan since the days of their HID Stadium lights, but I’m not impressed just from a business standpoint that they would sell two mainstream products that cannot work together.
25 July 2021 at 6:55 pm
Wireless is great but do I understand that the problem goes away if a wired bike computer is used?
25 July 2021 at 9:31 pm
Doug, You are correct, there isnt any issue with a wired bike computer.
19 September 2021 at 7:32 pm
I there too! My issue is interference between Cateye Padrone and NR Lumina 740 headlight. As soon as I turn on Lumina, Cateye stops functioning. Last time I buy a wireless Cateye product!

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