http://www.donour.com/cars/pyxede

There you will find a python datalogging program in it's infancy. It's nowhere near ready for an end-user, but most of you tech-heads should have no problem hacking together something for your needs. Like so many programming tool-builders I'm apt to get 95% of the way there and then stop because I have everything I, personally, need.

On a related note, I have code sitting at home that generates road dyno graphs, like the one dustin did in excel, without using excel. However, I'm a little hesitant to share them since I'm completely unconvinced that the nearest neighbor averaging techique is the best way to smooth the graph.

enjoy

d

WOW great work! Scrablems to find a mac

who cant type BOI.

????

Anyway, over the weekend I've done some thinking about how to do road dyno measurements and I've come up with what I believe is a pretty good way of doing data interpolation on dyno plots (actually the nod should go to some Chicago ERC researchers and the stata manual). I've coded it up to go with the data collection routine I wrote during the week.

For the Mac, I've written this plotting widget which should be able to display, scale, and smooth dyno plots in realtime. While not terribly useful in itself, you should be able (with a really straight long road) to perform multiple acceleration tests in a row and get a interpolated, reliable number very quickly. Oh, and it can generate pdf, postscript, jpeg, gif, or vector graphic version of the plots too (thanks here go to gnuplot).

Anybody interested now?

d

How accurate is the dyno data that you collect considering the road is nice, flat and straight? still interested. this would take the xede in a whole different direction, but won't this all be possible in the new xmap integrated with dataloglab using shiv's road dyno?

Accurate is a funny word. Technically speaking, you get numbers as accurate as any any other road dyno that measures RPM using the xede data logging protocol.

What you're really asking though is how well calibrated the numbers are. That's easy, they aren't calibrated at all They look just the same as those generated in the excel spreadsheet that dustin made:

https://www.evolutionm.net/forums/sh...d.php?t=135904

Very useful for performance analysis, completely useless for bragging or comparison to other vehicles.

Yes except for two very import things.

1) My software is and will remain free (http://www.gnu.org/philosophy/free-sw.html ), dataloglab is not

2) My software is specifically designed to be cross platform. It will run on Macs, windows, linux, and probably handhelds if anybody wants to take the time to work out the details.

EDIT: Oh, and I forgot to mention, I tested data logging speed over the weekend as well. I can easily log one variable (such as rpm) at 100hz. I've yet to try to get more than one I/O point at that speed. Actually I've been able to sample faster than 100hz, but doesn't seem to be useful given the speed of the xede hardware.



d

Here's an example of a torque plot on the same data dustin used for his excel spreadsheet. My own data looks similiar but I include this one so people can compare.

Note plots like these are generated AUTOMATICALLY during data collection. I'm particularly surprised that my interpolation method works as well as it does. Notice how all the important peaks in data can be seen but noise is mostly gone.

EDIT: test2 added (hp+torque)
d

Dustin's has pretty colors and a legend.

EDIT: I wouldn't mind helping you test this I have a couple ideas myself. It would be nice to have this over wireless and getting someone to help tune it across the globe. I know MalibuJack was working on this with the UTEC.

If you have ideas, I'm all ears. Testing really isn't needed unless you want to try it on weird platforms (windows, *bsd, handheld)

I'm not sure what you mean by wireless. It certainly wouldn't be difficult to send the data over the network for somebody else to analyze. You can do that with or without wires.

d

PS: I see you're in new mexico. How are you liking it? I'm moving to albuquerque in august.

If you don't mind sending me what you have. I want to test this on Windows and possibly on PalmOS.

What I ment by wireless is showing someone the data in realtime over a wireless network via wifi or satelite, almost like a live chat room. While the data is being pulled (while your driving the car) they are seeing exactly what is being logged at that time. I guess it could be the same as uploading, I know it would easy to upload the data to a server heck I have all my logs on a web server where I upload them too then I can access them when I'm not at home.

New Mexico has the best of both worlds. You have nice warm summers (not burning hot like phoenix) and you have nice winters, but not enough snow to where you can't see your neighbors house. We have some nice ski hills if your into that type of thing. What part of Albuquerque were you thinking of moving too? I can give you some tips on where the "warzone" is. Albuquerque has one of the highest crime rates in the nation for the size of the city, but your gonna find crime where ever you move. We also have a nice speedway which I have yet to visit. http://www.sandiamotorsports.com/map.htm We have a dragstrip as well, but I would rather take it to the speedway.

EDIT: I can't open the pyXEDE file. Anyway you can put this in .zip format? I don't have access to a unix machine to use gzip and winzip gives me a header error when I try to unzip it.

Yeah I can do that. I need to get things collected. Are you familiar with python?

This isn't very difficult. I'm not sure that getting the data in a realtime
method is that useful. The only real way to do this would across the internet, which
would kill your latency. It'd be good enough to talk about, but not good enough to react to engine conditions -- not even close actually.

While I'm thinking about it. This is nice and all, but how would you maintain a connection while on a track or road? 802.11's (wifi) range is quite short without an elaborate external antenna. Theoretically, you need at least 115kbs to stream an xede datalog. Obviously, there'll be network overhead. I expect twice that.

North East or rio rancho. I'm eager to talk more about it, but i'll take that converation out of this thread

d

Somewhat familar with python. I have used other languages (C, C++, PHP, PERL) haven't really messed with to much python, but it is just syntax. I'll pick it up quite quickly I'm sure.

About the wireless I'm aware of the latency factor, and I know that could slow it down quite a bit. The way I was thinking of maintaining a connection while on the track or road is through verizon's wireless broadband access. All you need is a a cell phone signal and you can have speeds of 400 - 700 kbps^ and they claim you can reach 2mbps speeds. I have a friend who uses this service I think it is $50/mo for unlimited use and I did a broadband test and was hitting around 550kbps with a 2-3bar signal. The card runs off of the PCIMIA slot.

Good area. I know we shouldn't get OT about this, but I would suggest Rio Rancho. Houses are CHEAP and it is a really nice area not to mention closer to the speedway. I'm looking at land in that area and plan to build a house there in the next couple of years. I live in Los Alamos btw. We'll continue this conversation some other time PM me if you want more info on NM.

Telemetry. I should have my Powerbook back this week. What do you recommend for cabling? USB to serial? Anyhow, keep up the good work.

I use this:

http://www.amazon.com/exec/obidos/tg...onics&n=507846

They keyspan adapters are known to provide the correct voltage for RS232 ports. A lot of house brand adapters tend not to. I also use it to connect to an inexpensive scantool that I got here:

http://www.scantool.net/products/index.htm

You can find software for the scantool on my website as well. As a matter of fact, If you bought two adapters, it wouldn't be difficult to data log from OBD and the xede simultaneously. The logging functions are modular by design.


Thanks.

donour

Release 0.2: more code, more stuff works. A screen shot (fancy colours). Link in first post.

Oops, I didn't see this. ZIP files added, although winzip should have no problems with tar.gz.

d