Help with data acquisition please
11-25-2007, 11:01 AM
#16
Rennlist Member
PCA National does not have any rules prohibiting the pacement of Beacons at the track, nor does it affect the insurance of the club. Some clubs like HVR and CVR encourage the use of data acquisition and do not have an issue with beacon placement during a DE.
Don't forget that a GPS system samples at 10hz or takes a reading of the sensors only 10x per second. There are better systems that do it at 20hz, but that is rare and usually only on the more expensive DAQ systems like MoTeC (as an option). At 120mph, there is considerable distance covered between the samples, so you won't necessarily get precise sampling measurement from GPS. Depending on what you are measuring it might be good enough, but for other things, it likely won't be good enough.
Don't forget that a GPS system samples at 10hz or takes a reading of the sensors only 10x per second. There are better systems that do it at 20hz, but that is rare and usually only on the more expensive DAQ systems like MoTeC (as an option). At 120mph, there is considerable distance covered between the samples, so you won't necessarily get precise sampling measurement from GPS. Depending on what you are measuring it might be good enough, but for other things, it likely won't be good enough.
11-25-2007, 11:13 AM
#17
Lifetime Rennlist Member
MoTec can use GPS as an add on. They also have video integration with any video you capture.
11-25-2007, 11:15 AM
#18
The thing that data naysayers fail to understand is that data is fun, at least to us geeks.
I highly, highly, highly recommend buying a system that is expandable (most are) because you may want to add more sensors as you go along.
Most data acquistion devices on the market can easily give you GPS position, speed, and RPM, as well as lat and long Gs. These are the very basics, and they are sufficient for newbies.
I must say I found data much, much more useful once I installed steering position, throttle position and brake pressure. Why? Because you are not always doing what you think you are doing, and unless you look at your inputs directly, you are trying to extrapolate your inputs by looking at the results. As such, the next time I do this, I will have steering position, throttle position and brake pressure from day one.
I highly, highly, highly recommend buying a system that is expandable (most are) because you may want to add more sensors as you go along.
Most data acquistion devices on the market can easily give you GPS position, speed, and RPM, as well as lat and long Gs. These are the very basics, and they are sufficient for newbies.
I must say I found data much, much more useful once I installed steering position, throttle position and brake pressure. Why? Because you are not always doing what you think you are doing, and unless you look at your inputs directly, you are trying to extrapolate your inputs by looking at the results. As such, the next time I do this, I will have steering position, throttle position and brake pressure from day one.
11-25-2007, 11:15 AM
#19
Nordschleife Master
Charlie, yes, I have a MoTeC ADL2 with most of the options enabled in my car and CAN linked to the other electronics in the car. The basic MoTeC ADL, ADL2, SDL all can use a beacon, or a 10hz or a 20hz GPS input, or both Beacon and GPS. I have not purchased the GPS module for my car because for what I'm doing, it does not buy me anything that I care about.
It depends on who's DAQ system you are talking about, and what sensors you are wanting to read. For instance, my car has linear potentometers on each shock and they are sampled at 1000hz, it also has a yaw sensor, 3 axis g-force sensor, infared tire temp sensor, steering angle, front and rear brake pressure, etc, the list goes on. I'm thinking of adding a second 3 axis g-force sensor, one for the front and one for the rear along with IR ride height sensors.
What does a good system cost?
11-25-2007, 11:20 AM
#20
Lifetime Rennlist Member
Charlie, yes, I have a MoTeC ADL2 with most of the options enabled in my car and CAN linked to the other electronics in the car. The basic MoTeC ADL, ADL2, SDL all can use a beacon, or a 10hz or a 20hz GPS input, or both Beacon and GPS. I have not purchased the GPS module for my car because for what I'm doing, it does not buy me anything that I care about.
It depends on who's DAQ system you are talking about, and what sensors you are wanting to read. For instance, my car has linear potentometers on each shock and they are sampled at 1000hz, it also has a yaw sensor, 3 axis g-force sensor, infared tire temp sensor, steering angle, front and rear brake pressure, etc, the list goes on. I'm thinking of adding a second 3 axis g-force sensor, one for the front and one for the rear along with IR ride height sensors.
It depends on who's DAQ system you are talking about, and what sensors you are wanting to read. For instance, my car has linear potentometers on each shock and they are sampled at 1000hz, it also has a yaw sensor, 3 axis g-force sensor, infared tire temp sensor, steering angle, front and rear brake pressure, etc, the list goes on. I'm thinking of adding a second 3 axis g-force sensor, one for the front and one for the rear along with IR ride height sensors.
I was concerned about the huge increase in spring rates and whether the calculated downforce would still work - well it works fine and I could see the massive increase in downforce this year, with the tunnels.
11-25-2007, 11:24 AM
#21
Nordschleife Master
Hi Mark,
We can chat offline. I'm not sure of what I'm seeing with the maths and the shock position sensors because I am not sure if my car has much downforce (stock body) or if the math needs to be modified (more smoothing) for a GT car rather than a formula car with downforce. This is why I want to install the IR ride height sensors, to get a "second opinion" if you will.
We can chat offline. I'm not sure of what I'm seeing with the maths and the shock position sensors because I am not sure if my car has much downforce (stock body) or if the math needs to be modified (more smoothing) for a GT car rather than a formula car with downforce. This is why I want to install the IR ride height sensors, to get a "second opinion" if you will.
11-25-2007, 12:10 PM
#22
Rennlist Member
11-25-2007, 01:14 PM
#24
Rennlist Member
Thread Starter
Join Date: May 2007
Location: Gig Harbor, WA
Posts: 791
Likes: 0
Received 0 Likes
on
0 Posts
I really appreciate evryone's input. I have looked at many of the vendor's web pages, and will talk with the guy who helps set up my car tomorrow. Right now I am still considering the Traqmate + Chasecam combo vs DaVid. I like the idea of video synced to data, but can see where brake pressure, throttle position, and gas pedal position would be very helpful.
Thanks again guys. Your willingness to share your knowledge is wonderful.
Thanks again guys. Your willingness to share your knowledge is wonderful.
11-25-2007, 01:22 PM
#26
Lifetime Rennlist Member
11-25-2007, 07:06 PM
#28
Moderator
Rennlist Member
Rennlist Member
Three settings on TraqMate -- 10, 20, and 40 Hz. Recording hours on the unit are: 22 hours at 10Hz, 11 hours at 20Hz, and 5.5 hours at 40Hz. If you bring your laptop to the track and are running something like Cups & Saucers (7 hours in 2 days), you can upload / clear after day 1.
11-25-2007, 08:20 PM
#29
Rennlist Member
11-26-2007, 12:15 PM
#30
Instructor
Join Date: Oct 2006
Location: NJ
Posts: 204
Likes: 0
Received 0 Likes
on
0 Posts
I have to agree with others, until you are more experienced, your time and money would be better spent doing more DE's than on a datalogger. That said, I have a TraqMate and really like it. Very easy to install and use. I use TrackVision to overlay the data onto video so I can review my videos with the data to see where I gained speed on certain laps and why. I'll then go into the TraqView software and really analyze the data to see exactly what I did to make that speed.
I record speed, RPM, thottle position, braking, G-Forces, lap times, track location, and track map.
See this video for an example with the data overlay.
Here is an overview of most GPS data loggers.
-Scott
I record speed, RPM, thottle position, braking, G-Forces, lap times, track location, and track map.
See this video for an example with the data overlay.
Here is an overview of most GPS data loggers.
-Scott
Last edited by sbarton; 11-27-2007 at 01:06 PM.