RossJ84

Hi all, I'm thinking of getting an OBD2 device to play around with, and I've seen a variety of ELM327 devices on eBay. Ideally I would use one of the Bluetooth ones (like this), then it can work with my Android phone, but I read in another thread on here that the update rate was pretty poor, i.e. once every few seconds... Can anyone confirm what the update rate is like on the Bluetooth devices?

Today I found some even smaller ones like this - anyone have any experience with them or should I stick to the larger trusty ones?

Thanks

Ross

lovegroova

I've got an Ebay special bluetooth one like you;ve linked to and it works a treat. Update rate is several times a second I think.

There's a video in this post which shows the data from the OBD2 in terms of the rpms

https://www.s2ki.com/s2000/topic/907...t__p__21907369

RossJ84

Hmmm, that is a bit slower than I was hoping (looks about once per sec, makes it a bit stuttery), do you know are all the wireless ones like that, and would I get a smoother update rate with a wired module?

Maybe I'm expecting too much of the bluetooth ones, I forget how slow BT is...



Ross

lovegroova

Not sure where you get "stuttery" from?

Looking at the data, it refreshes around 7 times per second.

The GPS runs at 10Hz and the Phone App is limited to 10Hz as well.

RossJ84

OK, it might just be the way it's overlaid on the video, what I mean is if you look at around 0:30-0:45 in the video, the speed/rpm jumps up in bursts every second or so, rather than a smooth increase. That may just be the way these things work, not used one before.

Just out of interest, is the current gear something that's logged by these or did you add that afterwards?

Thanks


Edit - I just scrolled up and noticed the first video on that page you linked, that's more what I had in mind! Was that using the same device?

lovegroova

All the same device, although in the first video, the phone was cutting off the rpm figure at 7000, so the true figure isn't shown.

I calculate the current gear based on the data in the file. Here's a link to a google docs spreadsheet that'll let you do it https://docs.google....cnE3dVRmeFB3SkE

Also, have a read of this thread from here onwards: https://www.s2ki.com/...st__p__21589307

What are you going to try to do with the data?

RossJ84

It's mostly out of curiosity, but I am hoping to start doing a few track days soon so just investigating my options for logging etc.

Also, as a computer programmer, originally my intention was to write some software to log data and show fancy displays, but since found out that there's such a huge amount of software available already that there's probably not much point!

Thanks for all the info,


Ross

Benjamico

Has anybody used a bluetooth adapter with an iPhone4? If so what app / software has worked well?

Cheers

Ben

lovegroova

AFAIK, bluetooth doesn't work properly/is crippled on the iPhone, so you need to use a (more expensive) USB adapter.

See my previously linked thread here for details. https://www.s2ki.com/s2000/topic/913...t__p__21587380

Benjamico

Thanks for the info Simon, I had a sneaking suspicion that would be the case!