|   computer instalation Q --------------- m | 3C
May 21, 2003 7:58 PM | | Does N1 know how to instal the receiver for the computer on the handlebar on Cannondale Scalpel with front LEFTY shock ?
I'm having very hard time to find place where to instal that receiver (got one which is wireless), but it does not meatter if it is with wire or not cuz there is not any space at all on the front LEFTY shock from the boot/brake rotor ........... any ideas as how to custom install it or any hints .... ?
ps: btw can not install it on the rear rim/frame cuz the lenght of the wireless signal is only 60cm. and if I get the one with wire, than the signal precision will not be the same cuz from the cable lenght (just A guess) ....
THX in advance =) |
| Warning! Long-winded engineering geek answer.... | FreeRangeChicken
May 22, 2003 8:11 AM | | btw can not install it on the rear rim/frame cuz the lenght of the wireless signal is only 60cm. and if I get the one with wire, than the signal precision will not be the same cuz from the cable lenght (just A guess) ....
That's totally bogus. The cable length does not make a bit of difference with respect to accuracy. The only thing a long cable will contribute to is latency, and I doubt that your brain can perceive the few picoseconds (trillionths of a second) of latency that a 36" cable will have compared to a 24" cable(typically the human brain can only discern a difference of a few tenths of a second). Latency is the delay between the time the sensor picks up the signal and the time the computer receives that signal.
Cycling computers measure distance by counting pulses, and speed by counting the number of pulses in a given time period. All of the pulses see the same amount of delay(or latency), therefore, the time between pulses is the same and accuracy is not affected. If there is a difference in accuracy between the cabled and wireless version of the computer you want, it is due to some other design factor, not cable length.
Actualy I would argue that the wireless can be less accurate in real life due to possible RF jammers. My girlfriend always complains that her computer stops working when she rides through a certain area. This area has a lot of RF transmitters. The wireless computers are nice because you don't have to deal with cable routing and it makes for a nice, clean install.
If you are really concerned about accuracy, make sure you take the time to calibrate your computer to your wheel size correctly.
Good luck!
FRC
Engineer |
| OT - thoughts on LED/tungsten taillamps... | GirchyGirchy
May 22, 2003 9:24 AM | | Your comment "typically the human brain can only discern a difference of a few tenths of a second" got me to thinking about car taillamps. Specifically, ones that use normal tungsten bulbs for the main brake lights and LEDs for the Center High Mounted Stoplights. The later Lincoln Mark VIII comes to mind too, with its normal outer lamps and neon inner lamp along the trunklid.
If you ever watch a car with these combinations, you can see the LEDs or neon bulbs light up faster than the tungsten lamps, and I was just wondering how long this delay is. Ever read/heard anything about that? Just curious.
Brian |
| More non-relavant babbling.... | FreeRangeChicken
May 22, 2003 12:18 PM | | Nope, never really read or heard anything about that. Though the two technologies work completely differently. An LED emits photons by exciting a semiconductor with electricity..... more accurately, by exciting the junction of two dissimilar semiconductor materials. The excitation of this material happens pretty quickly when voltage is applied.
An incandescent bulb works on a much more crude technology. It emits light by way of heating a material to the point that it gives off blackbody radiation at a frequency and and intensity that is perceptible by the human eye. This is the same principle that causes a piece of metal to glow when it is being welded. Running an electrical current through the filament of an incandescent bulb causes it to get hot, just like the wiring in houses causes fires when the circuit breakers don't work. When the filament reaches a high enough temperature, it begins emitting light. This process is pretty fast compared to human reflexes, but compared to the technology in an LED, it is extremely slow. The filament in an incandescent bulb takes time to heat up enough to emit light.
Side note:
Incandescent bulbs are highly inefficient because most of the energy they use is dissipated as heat, not light. LEDs a are much, much more efficient at converting electrical energy to light.... a much smaller portion of the electrical energy is converted to heat in LEDs.
Courtesy of dictionary.com:
in·can·des·cent
Pronunciation Key (nkn-dsnt)
1. Emitting visible light as a result of being heated.
FRC |
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