cycle computers

[cyclenic]

How exactly do they work?

 

[Lazy-Commuter]

Most (all?) have a little magnet doofa that goes on the wheel, and a sensor that goes on the fork leg. Sensor counts each time the magnet goes past and uses the circumference of your wheel to work out how fast you're going / how far you've been and all sorts of other clever stuff.

The sensor talks to the cmputer / display, which is usually mounted somewhere on the bars, via the gift of a wire or wireless.

 

[hackbike 6]

Seem to be very accurate as well.It's all done on maths and measuring the wheel circumference out and entering the figure into the cycle computer.At least that's what I did.

 

[yello]

There's this hamster....

 

[HLaB]

Most (all?) have a little magnet doofa that goes on the wheel, and a sensor that goes on the fork leg. Sensor counts each time the magnet goes past and uses the circumference of your wheel to work out how fast you're going / how far you've been and all sorts of other clever stuff.

The sensor talks to the cmputer / display, which is usually mounted somewhere on the bars, via the gift of a wire or wireless.

Just to add to the confusion, there's also GPS systems. Basically a signal travel back and forth from satellites and a gps receiver repeatedly. A computer then determines how far you've traveled, and speed = distance divided by time.

 

[gratts]

Just to add to the confusion, there's also GPS systems. Basically a signal travel back and forth from satellites and a gps receiver repeatedly. A computer then determines how far you've traveled, and speed = distance divided by time.

Humm..Won't this sort of device give a lag between the displayed 'live' speed and the actual speed one's traveling? It does on my brother's speed function on his car GPS..maybe these work differently though

 

[HLaB]

Humm..Won't this sort of device give a lag between the displayed 'live' speed and the actual speed one's traveling? It does on my brother's speed function on his car GPS..maybe these work differently though

It too instantaneous for lag to be a problem. I think it depends on the system as too the accuracy. I've found my Garmin Edge is quite accurate (within 0.1 to 0.2 mph to that clocked on my cateye) but my old Garmin Geko wasn't.

 

[02GF74]

Most (all?) have a little magnet doofa that goes on the wheel, and a sensor that goes on the fork leg. Sensor counts each time the magnet goes past and uses the circumference of your wheel to work out how fast you're going / how far you've been and all sorts of other clever stuff.

The sensor talks to the cmputer / display, which is usually mounted somewhere on the bars, via the gift of a wire or wireless.

no.
the magnet is attached to wheel and it goes past a reed swtich. this switch has contacts that close when the magnet is near to it.

the computer senses the contact by a pair of wires - either open or closed - and counts the number of times this changes in a given amount of time.

As the computer was programmed with the wheel diamter, it is able to calcuatate the speed.

Note that wireless bike computers have same arrangement but inside the sensor is a small battery powered radio transmitter that sends the same information, the computer has a receiver to receive this info.

 

[Lazy-Commuter]

no.
the magnet is attached to wheel and it goes past a reed swtich. this switch has contacts that close when the magnet is near to it.

the computer senses the contact by a pair of wires - either open or closed - and counts the number of times this changes in a given amount of time.

As the computer was programmed with the wheel diamter, it is able to calcuatate the speed.

Note that wireless bike computers have same arrangement but inside the sensor is a small battery powered radio transmitter that sends the same information, the computer has a receiver to receive this info.

er, isn't that more or less what I said?

 

[Mr Pig]

This is all very interesting but I'd like to hear the rest of the hamster story. What about him, what did he do? I hope it's not a sad story or one of those crap romance jobs.

 

[Chappy]

There's this hamster....