Aren't those the same as bicycle speedometer? I was looking at those today at the store, they have to use mounted sensors around the tire, which is an issue when you're talking about longboard wheels.
Quote:
Originally Posted by BenBanned
He talked about it in the post.
How about a helmet mount?
Can anyone think of an aero friendly way without compromising the safety of the helmet to mount?
Mmm... Only thing I could think, would be to mod a helmet so it has a tail on it (kinda like the Charly helmets) with that tail being an addition to the helmet, wherein the gps is somehow mounted inside that space. That leaves the question of direct site to sky, though if it uses some sort of antennae, you could leave that through, pointed skyward.
for a GPS to accurately measure speed it must have a 1/per second continuous refresh/update rate..
Quote:
In the case of navigation and logging GPS products, that sample rate is especially important. A Navigation product needs to take a sample at least every few seconds to accurately locate the receiver and provide correct navigation. However, in tracker (logging) products, they need to take a sample reading every second to accurately measure speed. Location, and travel direction are easy, but accurate speed measurements require more precise sample readings from the GPS satellites. A one second sample can accurately measure speed to +/- 1 MPH/1KPH, but some trackers take a sample only every 6-20 seconds which can induce significant error.
most $100-200 GPS's wont measure speed accurately.
heres a little somethin i found on the navman s300 and r300. The s300 is geared toward inline skaters and the r300 is geared toward runners.
S300 Features
Current speed
Average speed
Maximum speed
Speed target zone (with acoustic signal)
Distance skated
Automatic timer
Time (ultra precise GPS satellite atomic time)
Date
Changeable cover
Ideal for comparing performance with friends
Easy operation with only two buttons
S300 Technical Specifications
Battery life up to approx. 16 hrs
Water resistant
Battery indicator
Temperature range -10°C to +50°C
Dimensions WxHxD: 79 x 78 x 27 mm
Weight approx. 120g (incl. battery and arm strap)
Speed accuracy +/- 0.3 km/h
Distance measurement accuracy +/- 2%
R300 Features
Distance ran
Current speed / pace
Average speed / pace
Maximum speed / pace
Pace / speed target-zone (with acoustic signal)
Automatic timer
Distance run per lap
Lap history (max. 50)
Calories burned
Current altitude (GPS)
Time (ultra precise GPS satellite atomic time)
Date
Changeable cover
Pace control and programmable target zone
Easy operation with only two buttons
R300 Technical Specifications
Battery life up to approx. 16 hrs
Water resistant
Battery indicator
Temperature range -10°C to +50°C
Dimensions WxHxD: 79 x 78 x 27 mm
Weight approx. 120g (incl. battery and arm strap)
Speed accuracy +/- 0.3 km/h
Distance measuring accuracy +/- 2%
i picked up a few of the garmin 530 hcx... these are frs/gmrs two way radio communication devices with built in gps (having only one would be pointless). when you have a dialogue between two or more of these units they basically show up on your map so autolocation is the key purpose. it has a waterproof rating that's pretty low but better than most (it can get wet, just not to deep or wavy). great compass and trip computer, you'll not only know speed, direction, duration of movement and stops, virtical drop and rate of said drop, and way tmi. your radio has multi band communications (technically you should be licensed to use gmrs btw) and multiband weather.
now the best part is the gps with it's map displays. topo is your terrain info, city navigator gives you street and turn by turn directions, bluechart provides soundings and bathymetric charts of underwater features such as reefs and shouls... and there's more. the maps come at a price though and with this product it can get expensive. but like everything else, nothing is safe from a cleaver hack.
so what's the purpose of all this... using your topo you find the steepest roads in the area and check it against citynav for intersections and such... set your spotters who can contact you even if it is a long winding hill and you do not have a visual. take your run and record your track data (ie: speed, direction, gradient, etc) using the trip computer. along comes the man and you have to split... using the radios you know the exact location of the others especially if you have to disperse. another purpose is for finding the surf... weather radio lets you know the small craft advisories, bluechart gives you the underwater terrain to find the features that would offer potential for wave formation given the right weather pattern. using the radio you can do your soundings to catalogue these potential surf spots. get the picture?
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Last edited by shapeshifter; 08-14-2008 at 01:08 AM.
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wheels:abec no schools, abec lemon bigzigs, and 85mm speed vents
TRUCKZ: randals, seismics, bennet vectors, crail, and independents
BearingZ: rockin rons cermics, bones reds, and bones swiss six
Boards: evo, sector 9 38", some homemades, vangaurd, and mini sector 9.
I just scored a navman s300 for $55 shipped! Should be here on thursday, I'm stoked.
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Pray to fu*king god this guy I know of has not sold his, cause if not, I'll be one of the 3 to own one BITCH's!!!! It's to sexual not to own it. If I cant buy it me and my buddy are going to make one, witch will cost almost too much but fu*k it, I NEEED this board for my dh setup.
Evo, Lime BZ's, 50 degree randals (front flipped), Black JimZ bushings, Edger grip, Biltins
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Re: My research on Speedometers and GPS
check out the Venom Speed Meter for r/c cars, it costs about $30, runs on 4 AA and is pretty accurate, as it works by counting revolutions. You just install a magnet in one of the wheels, a sensor, and then set your final drive ratio (1:1 for skating) and wheel diameter. Has the same kind of functions, average speed, distance, top speed, etc.
How about a helmet mount?
Can anyone think of an aero friendly way without comprimising the safety of the helmet to mount?
SportVue MC1
I found this a few years ago.
I'm reading the manual PDF, and it looks like it uses a magnet on the wheel to determine speed and a 2nd computer module that is put somewhere on the bike. There is supposed to be a bicycle model, SportVue BC1, which may be easier to mod though I can't find crap about it.
There is a Skydiving model using GPS being released soon. Looks perfect, and expensive.
They say they do custom development services.
I'll shoot an email at them for some advice.
on the suunto watches the x10 has gps and my dad has one for hunting and marking his routes because you can download all your stuff to Google earth. And when it comes to on watch features its fairly stripped down to way points and just track logging.
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Re: My research on Speedometers and GPS
