Dave Wheeler wrote:
> I am starting development of a hobby project which will read a vehicle
> speed and do some stuff (Alarms for example) the project will eventually
> be
> PIC based but to get an understanding of 'real' things going on I am
> trying to find a Scantool to help. There are lots of ELM327 clones
> available from China but
> my research has helped me in deciding to keep clear of them. Other tools
> available in the UK vary in price (dramatically) and although my time
> for this application is free, I still don't want to waste a lot of time
> with inferior hardware.

Good idea. The problem with Chinese clones is not in that they don't ever
work; the problem is that you never know what you're going to get. Some
units work perfectly, some work marginally, some work on one protocol but
not the others, some don't bother powering up and some power up and catch
fire. I'm not exaggerating:

http://forums.fluxmedia.net/obd-ii-auto-diagnostics/6982-dealexteme-obd-usb-thoughts.html#post51292


> The ELM327 (V1.3a) based tools seem to be entry level and only
> upgradable by chip change, there
> seems to be some 'compatible' tools that are flash based and easy to
> upgrade (generally free).

The only devices with a bootloader that I'm aware of, are OBDPros and 
OBDLink (www.obdlink.com).

In my recent post, I alluded to the fact that ScanTool.net LLC is 
considering bringing a claim against OBDPros' founder, Jay Shroff. While the 
outcome of such situations is never certain, I would definitely consider 
this fact when choosing a vendor.


> The Elmscan5 seems like a good contender but the UK prices from
> distributors is high compared to direct, obviously the direct route may
> attract some import duty and the
> dreaded VAT.

My opinion is necessarily subjective, but I would get the OBDLink instead of
the ElmScan 5. One reason is upgradeability, and the fact that any real
problems you encounter will be fixed much quicker than with an ELM327-based
option. We've been selling ELM327 products for over seven years, and I'm
sorry to say that Elm Electronics has been very slow in implementing
customer requested changes, and fixing bugs.

The other reason is cost: Elm Electronics is not at all flexible when it
comes to pricing.


> Any suggestions, recommendation's or 'keep well clear of's'   will be
> greatly received

Take a look at the microOBD module:

http://www.scantool.net/scantool/downloads/44/microOBD-ProductBrief.pdf

It's based on the same firmware as OBDLink, and includes all necessary
drivers. We also have a nice development board that it plugs into, we plan
to post photos and descriptions of both on our website sometime next week.

Another option is to incorporate the STN100x chip into your device. The
downside is that it can sometimes take a while to work out the bugs in the
(deceivingly simple) driver circuitry.

Vitaliy

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