GPS vss options

Discuss which Sensors work best with these ECUs and share how you are using inputs and outputs
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

GPS vss options

Post by gnutz2 »

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.

Image

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.
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: GPS vss options

Post by Rob Stevens »

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 :)
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

Re: GPS vss options

Post by gnutz2 »

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 :D
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: GPS vss options

Post by Rob Stevens »

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?
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: GPS vss options

Post by Alex DTA »

I'd love to play around with the laser sensors, but that's time I don't have right now. One day.
PhillipM
Posts: 177
Joined: Tue May 13, 2014 5:30 am
ECU Model: S80 Pro
Distributor: DTA UK
Firmware Version: 73

Re: GPS vss options

Post by PhillipM »

5th wheel only works if they all stay on the floor!
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: GPS vss options

Post by Rob Stevens »

If your wheels are in the air, no amount of traction control, GPS, 5th wheel or laser is going to help!
:)
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: GPS vss options

Post by stevieturbo »

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.
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

Re: GPS vss options

Post by gnutz2 »

Haha, found a picture of a car today and instantly thought of this thread!

Best bit about it is it's hardly noticable :lol:



Image
PhillipM
Posts: 177
Joined: Tue May 13, 2014 5:30 am
ECU Model: S80 Pro
Distributor: DTA UK
Firmware Version: 73

Re: GPS vss options

Post by PhillipM »

Rob Stevens wrote:If your wheels are in the air, no amount of traction control, GPS, 5th wheel or laser is going to help!
:)
Nope, but your 5th wheel could be whilst the driving wheels aren't ;)

The reason I can't use traction control is because it lifts the front undriven wheels on the power :(
Post Reply