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Stan mentioned using data logging equipment in his air filter thread. I have a number of questions about that, and wanted to avoid a thread-jack. Of course anybody else is more than welcome to chime in.

You mentioned that you have the DL90? How has that been working? I had just done some research into data logging a few days earlier, and the DL1 (newer and more advanced version) was the most interesting option I found. I also just saw that they now have an option to sync video with the data, which looks ultimately cool.

The core functionality looks fairly obvious. My main questions are about the external sensors they offer. Do you have any of those, Stan? How difficult is it to hook them up? I would mainly be interested in steering angle and throttle position for now.

The DL1 also has an OBDII input, but I can't figure out how you would use that. I know that lots of potentially useful values (like throttle position, RPM's, etc) can be read off the OBDII port of a car. Could those be logged directly? Would additional hardware be needed, aside from a cable? They mention something about an "OBDII adapter", but I have no idea what that is.

Where and how would you mount something like this in an Elise? It's fairly compact, so it might fit behind the seat?

Any information would be much appreciated! :bow:
 

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OBD-II is a great way to get a bunch of useful parameters without adding any extra sensors.. RPM, TPS, airflow, coolant temps, O2, spark advance, "engine load", etc. Nicely standardized and easy to parse. Adapter boards to read the values from a laptop are very cheap and easy to build. I used the OBDTool software for years to tune my Eclipse.

Unfortunately, the data rate is so low as to be near useless for track applications, especially if you want to monitor more than one parameter. :( A lot depends on the car and how fast "over spec" it can communicate without trouble. You can't hurt anything trying, so why not..

I have great hopes for CANBus... if Lotus/EFU posts the useful sensors on the bus, we could get much more detailed information than is available on OBD-II.


I do have lust for the AP22. Their software looks incredibly good, especially with the GPS add-on.

On the other end of the spectrum, there's the G-Tech toy. I haven't been impressed with it. It's just a single-axis accelerometer, good only for back-to-back comparison runs with no quantitative units. Very touchy, very "approximate".

The Escort Passport GT-2 looks like a nicer inexpensive unit:
http://www.escortradar.com/gtimer.htm
I haven't tried one.
 

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Actually it appears the GTech "toy" has grown up. It is now a 3 axis device with recording capability. They have recently introduced one designed around road racing. It can record 2 hours of data at 10Hz. While it doesn't have the capability of the AP-22 with GPS, it is a lot cheaper and may meet casual needs. Also it appears some people have taken the output and used it to also produce road course mapping.

I was hoping someone here had bought the new one and had done some testing. I am considering purchasing one, but I don't race so I have no real need.

Greg

http://www.gtechpro.com/rr.html
 

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I have a Gtech Pro Comp...it's a toy. The software is not so hot either. Race Technology is the best stuff out right now, IMO. Play around on their web site and you'll find some good info about the software.

I've been using the AP-22 blutacked to the floor of my car ahead of the passenger seat. It's easy to adjust when needed. You can make a nice mount that secures to the car using the carpet hold downs too.

You can log nearly anything with the DL90 or DL1. On some Porsches the OBD2 port (located on the undersurface of the alloy shelf under the climate controls on our cars) can be used to power a DL90 / DL1 directly along with providing RPM data.

You can make some of your own sensors too...just make sure that you wind up with voltage values that are in a useful range, and you may need to send them a reference signal from a (2 dollar) three wire voltage regulator. Mostly 0-5 volts or 0 to 2.5 volts is useful.

I've had the DL90 since it came out a few years ago. The DL1 is definitely better. Mostly due to two things. The 5 hz instead of 1 Hz GPS. This is better and there is no real reason to do this faster in the future it appears. The 1 Hz rate is not that bad though...acceleromters alone tend to drift a bit after 20-40 seconds of elapsed time and either 1 or 5 Hz can prevent drift from being an issue.

I guess the best thing about the DL1 for me would be the compact flash storage. More convenient for downloads. With the DL90, again it's not that bad, it just entails either plugging into it while it's in the car, or unplugging it and then uploading it's data to your PC. If you wanted to do a lot of stuff a the track and analyze the data right there, the CF method is better since with a few cards you could have someone at the PC crunching numbers at a desk after being handed a card and yet the DL1 could still be gathering data if you load another CF into it. Both DL90 and DL1 can make GREAT track maps and are very interesting driver comparison tools. You can see where the expert drivers are finding their speed. Even by just using the datalogger with no sensors except it's own you can get tons of useful data about car performance and tune and driver factors.

For basic datalogging of the car at a higher level (and the driver) the main sensors would be GPS, Accel/braking g, lateral g, throttle position sensor position (from the car's TPS), brakes on or off (digital input), steering via pot and RPMs. The GPS and two accelerometers automatically get logged. Sometimes folks use a digital channel to "tag" certain parts of the data so a channel can be used for the driver to hit a button at or near a certain time on track they may be concerned about for example. For brakes the on/off from the brake light circuit is often enough unless you are measuring actual pedal pressure in which case you can use a sensor for that. I have not found that necessary since you get the actual braking result from the accelerometers. The most interesting sensor R-T is offering is the steering angle sensor since that shows what is happening with the steering wheel. Where it is and when and for how long and how fast it's moved and so forth. You can make your own sensor for this but the R-T version seems decent and would be convenient to order.

In my case there may be a trade-up deal available to go from DL90 to DL1. But I'm not sure how much it would really help me out. If you don't have such a unit and want one, get the DL1. You need a good laptop to go along with it since neither have a display. They really don't need one. Once you use their software and get used to it you are all set.
 

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Stan,
Do you have the new road racing software for the GTech Pro Competition? Ifso, how is it? I would think it would work OK for the casual user. Especially if you didn't want to spend what it takes to get one of the more sophisticated models on the market.

Greg
 

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Racer X said:
Stan,
Do you have the new road racing software for the GTech Pro Competition? Ifso, how is it? I would think it would work OK for the casual user. Especially if you didn't want to spend what it takes to get one of the more sophisticated models on the market.

Greg
I just downloaded the latest, but haven't given it a run yet in the WRX. It looks like it could have some benificial recording and analysis for you AutoX'rs. Records G's in all directions, leaves a mark for max in each direction. Even the "Drag' mode has been updated to give you 0-any mph-0 times, braking distance, etc. I have to say I am impressed with the updates, I still have to see if theay are accurate. It will be nice to compare the WRX to the Elise as well.

I realize now that I just babbled on and on, but basically I have a GTech Pro with the latest sw, but haven't tried it yet. I'll post some results as soon as I get a chance to test it out.
 

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>>>Do you have the new road racing software for the GTech Pro Competition? Ifso, how is it? I would think it would work OK for the casual user. Especially if you didn't want to spend what it takes to get one of the more sophisticated models on the market. <<<

R-T's software is basically the same for the different products. You can get pretty good results with the simple AP-22 and their software. The GTech software is much less flexible, configurable and capable. It also has been very slow getting out in the first place. Just try out the R-T stuf or look over the site. I told those guys long ago - get the analysis software right, the hardware is not that hard for anyone to do. I haven't checked lately but R-T generally has some sample data you can play around with to get a sense of things. It's really good stuff.
 

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Discussion Starter #8
Greg: I think the GTech-Pro should be a fine choice for what you're looking for. It's quite widely used, and I haven't heard anybody complain about it. So I think it must be good at what it's doing. A guy who autocrosses with me posted some recent data here:

http://www.solo2.org/ubb/ultimatebb.php?/topic/2/1811.html

Something like the DL1 is at least one level above that, in features as well as price. Among others, the main attractions for met are the built in GPS, and the option to use external sensors. I hope that recording data like steering angle could be extremely valuable to analyze your driving in competitive use, especially if you can compare to other drivers. I would also expect it to be more precise, even though that's hard to judge without studying detailed data sheets.

So it really depends on what you want/need. To measure some performance data for recreational use, the GTech-Pro seems perfectly appropriate. For improving car setup and driver in competition, it might be worth stepping up.

I'm still confused about the whole OBDII/CAN thing. Sorry if I'm a little slow on that, I'm a software person, and know just enough about electronics to be dangerous. ;) So my car has an OBDII plug that can be used to retrieve data from the ECU. The DL1 has a serial port that (quote from description) "can be configured to accept data from an external source - possible examples are data from the engine management unit, OBDii or CAN data (with a suitable adapter)." The way I understand this, I couldn't just connect the OBDII plug of the car to this serial port. There would need to be something in between that interprets the data to make it understandable for the logger? What is this "suitable adapter" they're talking about?

Good point though, Ground Loop, the data might be too slow anyway. I have a device (S.E.C.S.) that displays data from the OBDII port in real time (no logging), and it refreshes the values a few times a second.

Thanks everybody for the great answers.
 

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Where and how would you mount something like this in an Elise? It's fairly compact, so it might fit behind the seat?

Any information would be much appreciated! :bow:
I mount my DL1 on some aluminium plate covered with velro bolted down using the seat bolts. It sits just within reach to hit the start-stop logging button.

The GPS antenna was a little tricker - on a 'normal' car you just attach the magnetised base to the body of the car. The body of the elise of course is not magnetic, so I clamped some steel plate to the body near the rollover bar.

The DL1 logs are awesome - you know exactly where you lose/gain time on the track, sector by sector, and you can see where you are holding back by plotting the g-forces.

Cheers

NevB
 

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I'm working on rolling my own. Mainly because I have access to one of these from work. The plan is to integrate the inertial navigation with GPS to build the track map and get accelerations. I figure I can get the tack signal overlayed as well so as to be able to estimate hp. Maybe at some point I'll try reading the OBDII stream, but I think the inertial navigation should keep be busy for a while.

I like these winter car projects that can be done from the comfort of ones own living room, and don't involve any frozen fingers. :) Anyway, if anyone else wants to play with accelerometers, let me know, I'd be happy to share code.
 

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ConeFusion said:
So my car has an OBDII plug that can be used to retrieve data from the ECU. The DL1 has a serial port that (quote from description) "can be configured to accept data from an external source - possible examples are data from the engine management unit, OBDii or CAN data (with a suitable adapter)." The way I understand this, I couldn't just connect the OBDII plug of the car to this serial port. There would need to be something in between that interprets the data to make it understandable for the logger? What is this "suitable adapter" they're talking about?
Here's the deal with the DL1 (&AX22) serial port.. the data record simply stores the RS-232 stream alongside the datalogger stream. The unit itself doesn't parse it at all.. just stashes it away on the card. Bitrate is 115200, so the storage capacity depends on just how much / how often you send RS-232 data.

The decoding happens on the PC software side -- the Race Tech program will take all the RS-232 data, and "play it back" to a library of your choosing, which will then translate the serial data into parameters to give back to Race Tech s/w and plot.

It's a clever solution to a general problem -- how do you let the data record deal with every possible serial stream? Just capture it, timestamp it, and use the PC to translate it later.


So the hardware required in the car would be something to adapt your data port (OBD-II or CANBus) to an RS-232 stream that contains the data you are interested in, preferrably miserly in the reporting of it.

I have a few ideas for what might work great here, but alas, not yet a car to try them on..
 

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I'm working on something that will work with the G-Tech Comp. Pro with RR firmware and PASS 2.0 software. It will be a freebie because I have a day job and love this stuff.

The short history with all the gorey details... will be updated with any news.
http://www.socalspyders.com/modules.php?name=Forums&file=viewtopic&t=473

I'll keep this image updated:

Last night and today I added a resizable video window that you can play/pause/resume/restart an AVI in in perfect synch with the replay of the vehicle symbol on the track. Can you say Chasecam? (Hi, Randy! It was his idea about a year ago when we first discussed the future G-Tech Road Racing upgrade.)

I'm about to add a small floating graphic display that you can stick in one place or have follow the vehicle showing bar graphs similar to the G-Tech display in Road Racing mode. I'm also going to have a "tooltip" type thing show some or all vehicle dynamics (see right side of display) for whatever point on the track the cursor is closest to.

Currently I have problems with a separate program that does the Dead Reckoning. Some problems are easier to solve than others.

By the way, I'm an MR2 Spyder owner, a very jealous one at that. You folks have the ultimate Spyder.
 

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Kevin, that is awesome! Great work, keep it up, keep us posted and welcome to the board. I have a GTech, and can get more data for you if you need it.
 

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If you or anyone else has saved data (RR mode) and an AVI to go with it I could do some testing. It would be appreciated and we would both benefit. It would be nice if the AVI started at the same time as the data logging (for now... later on I'll work out a way to synch up the start). Starting the AVI earlier than data logging and both starting before launch would be great. At some point I'm going to add the capability to overlay all the graphics on top of a satellite image and could maybe start working on that, too, so if you know the lat/long of the start point it would be a bonus.

EDIT: It doesn't matter if AVI starts before or after G-Tech. I added that capability to skip forward in the AVI or track as necessary.

I think I'll have two modes for the program(s), road racing and autocross. I'd like to focus on autocross at first, so data/video for that would be preferred.

Thanks.

Admin/Moderators: If you would rather me do all this discussion/reporting of my software in a separate topic, just give me a shout.
 
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