interesting cateye computer

[bicycletricycle]

This looks nice. anyone seen one in the wild?
https://live.staticflickr.com/65535/50249442197_3ed9a00103_z.jpg (https://flic.kr/p/2jynwv4)Screen Shot 2020-08-20 at 4.37.28 PM (https://flic.kr/p/2jynwv4) by bicycletricycle666 (https://www.flickr.com/photos/24583601@N08/), on Flickr

[9tubes]

Love it. A modern version of the 1980s two-button Avocet.

I like the old-timey style LCD numbers too, like an old clock radio.

[reuben]

the 1980s two-button Avocet.

Loved mine. So easy to operate.

[fa63]

We just ordered one for the shop; it should be here tomorrow! I am curious to see it in person.

[sw3759]

very cool! had not ever seen one of those and a quick search looks like they have been around for over a year.
looks like a more modern approach for people like me that still just use a basic non gps bike computer and gets the head unit off the bar top.
hard to beat 41 grams complete but not sure how much those gps units weigh.
the sensor is bit obtrusive looking though.

may be a stupid question but i have not found a definitive answer

anyone know how those gps units measure speed do they still require a sensor or does the gps track speed :confused:

[ColonelJLloyd]

may be a stupid question but i have not found a definitive answer

anyone know how those gps units measure speed do they still require a sensor or does the gps track speed :confused:

GPS or both.

[sw3759]

GPS or both.

thanks,but curious but why would you need both if the gps picks it up?

[ColonelJLloyd]

thanks,but curious but why would you need both if the gps picks it up?

I typed "or". :)

GPS signals can be lost in heavy tree cover, tunnels, etc.

[sw3759]

ok thank you.i had been interested in one to try mainly if you were able to do away with sensors but it sounds like you still have to have one.
assume they still use the typical magnet pickups like always ?

[ColonelJLloyd]

ok thank you.i had been interested in one to try mainly if you were able to do away with sensors but it sounds like you still have to have one.
assume they still use the typical magnet pickups like always ?

I'm not sure how I've confused you, but you are not required to have a speed sensor in order to display and record speed with a modern GPS head unit. I do on one bike because I purchased a bundle that came with heart rate, cadence, and speed sensors. I do not move the sensor when I ride a different bike. I haven't noticed any hiccups on rides using that bike sans hub-mounted sensor. Anecdotally, I think the majority of people do not use a speed sensor in conjunction with the head unit.

Lastly, the modern speed sensors do not use a magnet. I've read they use some sort of magic.

[sw3759]

the modern speed sensors do not use a magnet. I've read they use some sort of magic.


thanks for the explanation.i had done some research but never found any real explanations on how these units actually measure speed but i couldnt recall seeing a pickup anywhere on gps equipped bikes.
assuming by magic your referring to ANT or bluetooth

[ColonelJLloyd]

thanks for the explanation.i had done some research but never found any real explanations on how these units actually measure speed but i couldnt recall seeing a pickup anywhere on gps equipped bikes.
assuming by magic your referring to ANT or bluetooth

That's how they connect to other devices. I assume they use some sort of accelerometer to calculate speed, but I'm not certain.

[Mark McM]

very cool! had not ever seen one of those and a quick search looks like they have been around for over a year.
looks like a more modern approach for people like me that still just use a basic non gps bike computer and gets the head unit off the bar top.
hard to beat 41 grams complete but not sure how much those gps units weigh.
the sensor is bit obtrusive looking though.

may be a stupid question but i have not found a definitive answer

anyone know how those gps units measure speed do they still require a sensor or does the gps track speed :confused:

Cateye doesn't make any GPS computers. The Quick uses a standard wheel magnet sensor.

Magnet-less sensors use accelerometers. The accelerometer detects gravitational force. As the sensor rotates, the direction of gravity (relative the sensor) also rotates, so these sensors simply measure the rate at which gravity changes direction. The rotation rate of the sensor is then multiplied by wheel circumference.

As far as why GPS computers use speed sensors: As mentioned previously, GPS receivers can occasionally lose signals, as when under trees or underpasses. But more fundamentally, GPS does not provide very accurate speed measurement for slowly moving vehicles (like bicycles). Wheel sensors provide far more accuracy. (Likewise, even though GPS can be used to calculate altitude changes, most GPS computers still use barometric sensors because barometric sensors provide more consistent measurements.)

[m_sasso]

Can be used with this Cateye Slim magnetic wheel/speed sensor, which is much smaller and not much thicker than the CR2032 battery, "O" ring strapped to your inner fork leg. Much cleaner appearance.

https://cdn11.bigcommerce.com/s-ki97g/images/stencil/1280x1280/products/2011/4365/cateye_slim__09838.1473526983.jpg?c=2

[bicycletricycle]

how do you adjust that sensor so that it is close enough to the magnet?


Can be used with this Cateye Slim magnetic wheel/speed sensor, which is much smaller and not much thicker than the CR2032 battery, "O" ring strapped to your inner fork leg. Much cleaner appearance.

https://cdn11.bigcommerce.com/s-ki97g/images/stencil/1280x1280/products/2011/4365/cateye_slim__09838.1473526983.jpg?c=2

[m_sasso]

how do you adjust that sensor so that it is close enough to the magnet?

This sensor seems to work with a much larger air gap, currently set up running at 1.0cm from the magnet, but haven't tested max distance.

Cateye tech manual reads 5mm or less, however mine seems to be working fine at 1.0cm, certainly on a lower fork leg you could position it much closer. On the inside of my Time Stiletto fork I have it set 7.5 cm below the fork crown, hard to see it is even there.

[reuben]

how do you adjust that sensor so that it is close enough to the magnet?

Slide it up or down the fork. Works quite well on my bike.

[sw3759]

Cateye doesn't make any GPS computers. The Quick uses a standard wheel magnet sensor.

Magnet-less sensors use accelerometers. The accelerometer detects gravitational force. As the sensor rotates, the direction of gravity (relative the sensor) also rotates, so these sensors simply measure the rate at which gravity changes direction. The rotation rate of the sensor is then multiplied by wheel circumference.

As far as why GPS computers use speed sensors: As mentioned previously, GPS receivers can occasionally lose signals, as when under trees or underpasses. But more fundamentally, GPS does not provide very accurate speed measurement for slowly moving vehicles (like bicycles). Wheel sensors provide far more accuracy. (Likewise, even though GPS can be used to calculate altitude changes, most GPS computers still use barometric sensors because barometric sensors provide more consistent measurements.)

thanks Mark,yes i understood the cateye quick uses the same type of pickup as my other cateyes,i use the strada slim wireless on several of my bikes it works fine.
yes my confusion was on the gps units as i have never owned one or really ridden with anyone using one that i payed attention to or asked questions about speed sensors,just did some googling and never found any type of explanation probably didnt dig deep enough.i was pretty sure "magic" wasn't it either and i guess i am in the minority regarding bicycle gps knowledge

if anyone was wondering those cateye slim sensors are too wide to use on a fork with steel blades.need wide flat blades for it to fit decently

[Mark McM]

yes my confusion was on the gps units as i have never owned one or really ridden with anyone using one that i payed attention to or asked questions about speed sensors,just did some googling and never found any type of explanation probably didnt dig deep enough.i was pretty sure "magic" wasn't it either and i guess i am in the minority regarding bicycle gps knowledge

Whether it is a magnet type speed sensor, or a magnet-less speed sensor, or GPS, all digital speed sensors essentially use the same method - they take a set of descreet distance measurements, and divide the distance between measurements by the time between measurements to get velocity (speed). In the case of the wheel based sensors, they measure rotational rpm and multiply by circumference to get distance; in the case of GPS, they use distance between two GPS position calculations.

The problem with GPS speed measurement is that the position error can be quite large compared to the distance between measurements. For example, if you are going 15 mph, you going 6.7 meters per second. If you calculate GPS position once per second, but one of the GPS positions is off by 1 meter, that's a significant percent of the distance traveled in a seconds. That 1 meter distance error could result in the measured speed being off by up to 1 m/s, or 2.2 mph. In contrast, speed measurements with wheel sensors are rarely off by more than 0.1 mph.

GPS is great if you want to know the position of any point on the earth by a few meters. But if you want to know the distance between two points that are close to each other, GPS position error can be a significant percent of the distance measurement. In that case, you'll get a more accurate measurement with a tape measure, or by using a measuring wheel of known circumference (i.e., a wheel sensor).