Datalogging

[djr81]

Been looking for a new logger which which records both GPS based accelerations etc & rpm. This thing appears to do both for a reasonable price. Anyone heard of them or used them?

http://www.starlane.com/en_Athon_GPS_multi...onal_chrono.htm

[dazmo]

Have not heard of or used this product but will be installing a data logger in my R33 race car soon I am useing a ruzic engineering data logger Paul the guy that makes them is in the final stage of finnishing the production model should be a verry good unit with local support and back up as well as future software upgrades. check his stuff out at www.timeattack.com he is also a user on this forum user name mountainrunner and one hell of a nice guy. I think his unit will do everything you require.

[djr81]

Yeah saw that. You will notice some idiot called djr81 posted in it.

Check Pauls thread about his data logger for its specs.

[hrd-hr30]

doubt Paul's data logger has anything to do with GPS or lap timing.

I saw a thread on the same thing over at the IPRA forums earlier in the week - might be helpful:

http://www.techmasters.com.au/forum/viewto...?f=2&t=3802

[hrd-hr30]

  djr81 said:

Yeah saw that. You will notice some idiot called djr81 posted in it.

lol, I probably would now...

[sav man]

what about the v-box mini? it looks identical to the perfomance box, but you can get a modual to put inputs from the car into it.

[djr81]

  sav man said:

what about the v-box mini? it looks identical to the perfomance box, but you can get a modual to put inputs from the car into it.

Not seen that before. Rpm traces tell you alot as do TPS & others. Shame no one makes it easy to tap into the few extra inputs that can add so much useful info.

Anyway the performance box is <$1000 but so is the Starlane gear too. The Starlane stuff appears to have more functionality for the dollars.

[sav man]

on the vbox site they have a heap of input moduals, should be able to get a rpm and tps trace. wouldn't be cheap though (nothing ever is )

[djr81]

Thats what sh!ts me. GTR's have TPS, steering wheel angle, front torque %, RPM, wheel speed all there for the taking. But without spending large amounts of cash you can't log them.

[sav man]

i got my datalogit box to log front torque %, was going to get round to logging brake (unfortually the brake is a 24v switch) and steering angle. If the Datalogit had memory it would almost be perfect, cause i'm not a fan of laptops floating round the car at the track.

[hrd-hr30]

vbox mini is the driftbox. performance box is the cheaper version of that without the yaw sensor. can get the performance box for $850 from Racer Industries. Its a little bit pricey for what it does in lap timing mode - lap time, up to 6 split times and speed at splits.

[MountainRunner]

Yes my Logger does do GPS and Lap Timing. Buts thanks for the usual uniformed commentary hrd-hr30. One day you will get over the AWD Shoot-out incident and stop trying to sledge me. lmao.

On a more serious note, there are a lot of loggers on the market these days and they all have their pro's and cons. Its about finding one that best matches what you are trying to achieve. For driver analysis you probably want to be at least logging; Throttle Pos, Steering angle, LatG, LongG, RPM, Speed, GPS is good for lap times and driver lines easy split times etc.

I've built my logger because I like to build electronics for cars such as my Torque Split Contoller and new Engine Monitor. I spend the extra time to make them marketable because a lot of guys who see what I'm up to want one and it also helps pay the development costs. The other thing is, when I've built the system its easy to modify it and enhance it with feedback from myself and other users. Its always nice to be able to add a feature or function when it can enhance the product.

For comparison I have loaded the current specs into the other Datalogging thread I started a while ago. These are the specs the beta system will have on release. There is a bit of detail there but as an overview:

10 x Analog Inputs (6 at 20Hz and 4 at 25Hz)

2 x Rate Inputs (RPM, Wheel Speed etc)

2 x Digital Inputs (brake pedal, clutch etc)

4 x Outputs settable as less than or greather than on any channel

GPS Input at 1Hz or 5Hz for track mapping and lap timing. This is also output to my Engine Monitor if it is connected.

Logging is done straight onto a USB key. No downloading and no memory constraints.

There is USB connection to the Laptop for configuration. (but not needed in the car as you point out sav_man you dont want to have to drive around with it)

6 of the analog channels can be used to sniff off factory or other system sensors, so no need to double up.

4 of the analog channels have build in 1K drive resistors to run sensors like Oil Pressure / Temperature which are not usually on factory cars (not good ones anyway)

I've included a serial port to connect the RaceLogger to my Engine Monitor so you can expand the logging to included all those channels also (6 more analog, 2 more rate). Plus the Engine Monitor can then display data from the RaceLogger.

Also you can daisy chain my 4WD Controller serial signal into the serial port of the RaceLogger and log the LatG, LongG and 4WD Split.

The data analysis sonftware will be an open development feeding in all ideas etc from the users of the system. I'm looking forward to seeing where we can take it.

[djr81]

From what I have tried I have found that GPS based position information if much better than the accelerometer based data simply because it allows you to plot your speed trace versus distance which is much more usefull than having it versus time. It highlights the small gains you end up looking for.

[MountainRunner]

The accelerometer data is very useful when looking at oversteer/understeer for in/through/out of a corner. It really depends what your looking for, which makes up the best combination of sensors for a given analysis.

[djr81]

  MountainRunner said:

The accelerometer data is very useful when looking at oversteer/understeer for in/through/out of a corner. It really depends what your looking for, which makes up the best combination of sensors for a given analysis.

Sorry I may not have explained myself well enough. You can easilly derive acceleration data (ie lateral & longitudinal) from GPS position data. What I was trying to say was that presented graphically it is more useful when plotted against distance than against time.

It makes it easier to see what was happenning at a certain point on the track rather than a certain time into the lap.

Hope that makes sense.

Straightforward accelerometers don't do distances well because they get messed up by hills & gradients etc.

[hrd-hr30]

  MountainRunner said:

Yes my Logger does do GPS and Lap Timing. Buts thanks for the usual uniformed commentary hrd-hr30. One day you will get over the AWD Shoot-out incident and stop trying to sledge me. lmao.

GPS Input at 1Hz or 5Hz for track mapping and lap timing.

well laughing boy, maybe I should have been clearer. it doesn't have built in GPS fuctionality like the other units being discussed.

but it CAN log GPS and lap times, IF you connect an external GPS unit, and you can even see your lap times on the fly like any other lap timer IF you add the engine monitor.

anyway, lmao right back at ya if you actually mean what you said - lap timing at 1 to 5hz.

1hz = timing to the second

5hz = timing to 0.2 of a second

I think most people would be looking for tenths as a minimum resolution for lap time information to actually be useful/meaningful. So it doesn't really do lap timing either.

[MountainRunner]

You were never going to win the AWD Shoot-out dude. Let it go. Breath in, breath out. Drink a soothing tea. Again LMAO at your persistence at sledging me, its the funniest shyte I read on the forums. Seriously dude let it go. No one cares. Try to contibute positively to the community instead.

By the way, if you think the speed the GPS data arrives is the same as the accuracy it can lap time at, then perhaps you should keep out of the technical discussion.

[hrd-hr30]

  MountainRunner said:

You were never going to win the AWD Shoot-out dude. Let it go. Breath in, breath out. Drink a soothing tea. Again LMAO at your persistence at sledging me, its the funniest shyte I read on the forums. Seriously dude let it go. No one cares. Try to contibute positively to the community instead.

By the way, if you think the speed the GPS data arrives is the same as the accuracy it can lap time at, then perhaps you should keep out of the technical discussion.

if you're using GPS signal to determine where the car is in relation to a start/finish line, and you only know where the car is at best every 0.2 of a second, you have a resolution of 0.2sec with an accuracy of +/-0.4sec as you have to cross that nominated start finish line twice per lap to start and stop the timing. Any times you give to an apparently greater accuracy are just approximations based on interpolation of the data - at best.

[djr81]

According to the nice folk at Starlane their logger works at 5 Hz.

[MountainRunner]

Yea it would do. You can get 5Hz GPS for a reasonable price. You just have to decide on the precision and accuracy as well at purchase.

As I was saying above, the timing accuracy is not just based on the GPS location data. You also use the equations of motion and most also use GPS-INS techniques. Its pretty mature technology and you should look at the specs on the system as a whole and not just a sub-system of the device.