[Ovmsdev] OVMS Hardware v2.0

Tom Saxton tom at idleloop.com
Fri Jun 8 23:42:24 HKT 2012

This is great stuff, Mark. I'm glad to see OVMS moving forward.

As a Leaf owner, the number one thing I want in an OBD gizmo is a visible
SOC meter in the cabin. The stock SOC instrumentation on the Leaf is worse
than useless and being able to see an actual SOC estimate easily adds 10% to
the usable range of Leaf. We have the Gary Giddings SOC meter in our Leaf
and it makes us feel empowered to really drive the Leaf to its full

In order for OVMS to go mainstream for Leaf owners, it will need to support
some sort of display. This could be an external display driven from the DIAG
DB9. Having power on that connector would be a big bonus.

The Leaf OBD port has two power lines, one that's always on and one that's
on only when the car is on. It would be great to pass the car-on power
through the DIAG DB9. (Unfortunately, that power line is off when the car is
charging unless you turn the car on, so it probably doesn't make sense to
power the OVMS board from there. Gary's box has a switch so you can manually
select the power source, which is handy when we want to monitor a charge.)

On a somewhat related note, when I display the Roadster at a car show, I
print out a sheet of paper that says "25,536 Oil-Free Miles Driven" with an
estimate of what my odometer will say when I arrive at the show. I have this
fantasy of putting an LED reader board in the rear window that shows that
message with the live odometer reading.

Is there enough room in the V1 board flash to push reader board command
strings out of the DIAG DB9?


on 6/7/12 5:33 PM, Mark Webb-Johnson wrote:

> Apologies for the length of this eMail, but lots to go through...
> We've come to the end of our initial batch of boards, and there are
> significant minimum-order-quantities for things like circuit boards, so we are
> taking the opportunity to switch to hardware v2.0.
> The roadster owners who wanted something like this presumably already have it,
> or are waiting for Tesla's solution. So, we're trying to think mostly of the
> _other_ cars out there. Things like the Volt/Ampera, Leaf and my wife's ICE
> Nissan children ferry.
> The problems we've had with the current hardware include:
> Production reliability issues with the factory
> Quality issues (particularly soldering) with the factory
> Too fiddly to produce and too many components
> Too hard to diagnose problems
> QC and Logistics is just a hassle for Sonny and myself - not fun ;-)
> Once we add in using this in other cars, we also get:
> Concerns over 12V battery load
> Lack of GPS in some cars
> Things got better as the existing hardware went from 1.0 (initial prototype
> with RJ11s) to 1.1 (kludgy developer prototypes with glued-on adaptor cables)
> to the current 1.2 (little white 4pin and 2pin connectors), but still just too
> much work to get these made.
> Accordingly, what we are trying to do is come up with a v2.0 hardware design.
> As what we have works so well, there seems little point in making any dramatic
> shifts - we've considered switching to a 32bit processor, built-in
> touch-screen display, etc - as that would be something completely different.
> We just want to incrementally improve the points that are 'hurting' now. Keep
> it a very low cost module that does what it does well.
> Here are the changes we have come up with:
> Change to a single-board approach, made by a single factory. The board will
> contain the controller and SIMCOM GSM/GPRS system in one.
> The board external connectors will be exposed through the box. We'll use a
> standard DB9 (male), then adaptor cables from that to each car's requirements.
> Pins are #2 CAN-L, #3 GND, #7 CAN-H and #9 +12V.
> The existing diag DB9 (female) is unchanged, but should be externally
> accessible.
> IPC pins to also be externally accessible, so firmware can be updated without
> opening the case.
> Upgrade the processor from 2680 to 2685. Gives us more flash (useful for cars
> other than roadster), but otherwise completely compatible.
> Connection of 12V line to microprocessor ADC. This will allow us to measure
> supply voltage and take appropriate actions.
> Upgrade SIM900 to SIM908, to give us optional GPS for cars that don't have it
> - this can be powered up/down by AT commands.
> LEDs go to the bottom of the board, to be closer to the holes and hence more
> visible.
> QC and logistics done in china - a partnership with a website there to handle
> order processing and logistics from stock.
> I really want to make something very very clear - this is not intended as an
> 'upgrade' for existing v1.x modules for roadster owners. The Tesla Roadster is
> covered, and work really well with v1.x hardware. New roadster owners will be
> able to use v2.x hardware as well, but there is no point in 'upgrading' from
> v1.x to v2.x hardware, for Roadster owners. The new v2.x hardware is primarily
> intended to make it easier so support other types of cars.
> As I mentioned at the top of this email, we're down to the last few v1.x
> modules - there was a recent unexpected rush of orders. So, today, we've taken
> down the hardware offering at www.openvehicles.com, until the v2.x hardware
> arrives. If someone _really_ needs a v1.x module, we still have some and can
> let you have it, but we really want to keep as many of the modules we have
> left as repair spares for existing owners.
> For those working with us on OVMS in other cars (Michael on Volt/Ampera, etc)
> don't worry - we'll look after you and swap you v2.x hardware if necessary.
> We're just now entering prototype stage with the factory, so if anyone has any
> comments/suggestions please send them in. I'm working hard on this. So long as
> the prototypes are ok, we should have production ready in 4-to-6 weeks.
> Regards, Mark.
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