Just looking at my options to get a vehicle speed input via gps and a quick search came up with this aem gauge.
http://www.aemelectronics.com/?q=produc ... s/GPSspeed
Looking at the manual it would be simple to wire into the undriven wheel input.
So does anyone know of something that would do a similar job but maybe cheaper and a faster sampling rate, 20hz would be nice as I would like to experiment with the traction control on my 4wd car.
And has anyone had any experience with some kind of IR sensor pointing at the ground?
Many thanks Baz.
GPS vss options
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Re: GPS vss options
I can see the idea in principal but I'm not sure you could ever get traction to work like this well.
I just don't think the GPS could ever be fast enough or accurate enough. I have an RT DL1 data logger and this uses both GPS and a 3 way accelerometer to calculate car speed, even then it doesn't always match my un driven wheel speed.
With the GPS you loose signal if you go under trees also.
Perhaps one of those ground speed reading lasers or how about a 5th bicycle wheel hanging out the back
I just don't think the GPS could ever be fast enough or accurate enough. I have an RT DL1 data logger and this uses both GPS and a 3 way accelerometer to calculate car speed, even then it doesn't always match my un driven wheel speed.
With the GPS you loose signal if you go under trees also.
Perhaps one of those ground speed reading lasers or how about a 5th bicycle wheel hanging out the back
Re: GPS vss options
I watched an interview with Andy forrest about his subaru, I can recall him talking about the traction control on the syvecs and using a 20hz gps signal for the ground speed.
I'm open to suggestions, like a fifth wheel
I'm open to suggestions, like a fifth wheel
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Re: GPS vss options
Get a DL1 data logger, the later ones have PWM outputs so you could send the GPS (they do a 20Hz) + accelerometer to the DTA as a wheel speed, but will set you back probably £750
Or go the 5th wheel route, you would probably have this working in a couple of days not sure if your mate will miss their old bike?
Or go the 5th wheel route, you would probably have this working in a couple of days not sure if your mate will miss their old bike?
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Re: GPS vss options
I'd love to play around with the laser sensors, but that's time I don't have right now. One day.
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Re: GPS vss options
5th wheel only works if they all stay on the floor!
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Re: GPS vss options
If your wheels are in the air, no amount of traction control, GPS, 5th wheel or laser is going to help!
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Re: GPS vss options
As Andy said, there is no reason GPS will not work for a speed signal.
BUT...and it is a huge BUT. It will rely on a good GPS signal.
Both my VBox and Plex dash struggle when there is tree cover etc, and even buildings sometimes.
Oddly on the logs it's not so much droputs, but at some hillclimbs the speed reading has just been lower than actual speed of the car, and it's always tree cover that seems to do it. Roadspeed would have climbed, but the GPS readings whilst climbing are lower than actual, which would clearly play havoc with TCS if this was the undriven wheel speed signal.
This has nothing to do with the refresh rate of the GPS unit itself either.
BUT...and it is a huge BUT. It will rely on a good GPS signal.
Both my VBox and Plex dash struggle when there is tree cover etc, and even buildings sometimes.
Oddly on the logs it's not so much droputs, but at some hillclimbs the speed reading has just been lower than actual speed of the car, and it's always tree cover that seems to do it. Roadspeed would have climbed, but the GPS readings whilst climbing are lower than actual, which would clearly play havoc with TCS if this was the undriven wheel speed signal.
This has nothing to do with the refresh rate of the GPS unit itself either.
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Re: GPS vss options
Nope, but your 5th wheel could be whilst the driving wheels aren'tRob Stevens wrote:If your wheels are in the air, no amount of traction control, GPS, 5th wheel or laser is going to help!
The reason I can't use traction control is because it lifts the front undriven wheels on the power