[Ovmsdev] Add +12V ignition detection in OVMS HW v3.3? (was: VW e-Up: CANopen & CAN-ID scan results)

Mark Webb-Johnson mark at webb-johnson.net
Mon Aug 3 10:21:37 HKT 2020

It is hard to modify the main board, without voiding the certifications we have (and going through the expense of re-certifying).

Simplest would be to implement this on an expansion board. Perhaps extend the K-line board we have to do other functions (12v switched status, relay control, etc)?

The DB9 is full (all 9 pins assigned), so this would have to be via DA26.

We have been using the EGPIO lines for system use, starting at #0 and working upwards:

#0 MDM_EN (modem enable)
#1 SW_CTL (external 12v control)
#2 CAN1_EN (can#1 enable)
#3 MDM_DTR (modem DTR)

Then expansion boards should start at #9 and work downwards:

#9 K-line enable (on k-line expansion board)

I guess we need just a simple voltage divider, and pull down, to determine on/off state of switched 12v?

Regards, Mark.

P.S. I have been hoping that Espressif would release a successor to the ESP32 with more RAM and GPIO pins, but it looks like the prefer to go lower performance/spec, rather than up.

> On 2 Aug 2020, at 5:47 PM, Michael Balzer <dexter at expeedo.de> wrote:
> Mark,
> I remember the current Leaf also has the issue of the OBD port being
> filtered by a gateway to only support polling.
> I think we should generally add a +12V ignition signal detection to the
> next OVMS hardware revision, i.e. without the need to add extra hardware.
> There is no standard for the ignition / switched +12V being available at
> the OBD port, but I think most cars will have that. If a car doesn't, it
> should still be easy to get from around the OBD port (e.g. fuses).
> Regards,
> Michael
> Am 02.08.20 um 11:03 schrieb Soko:
>> Meaning: We need a special VW-cable (like for the NIssan or Kia Soul)
>> with OBD Pin1 gets into a pin on the DB9 connector and into a
>> Digital-In-Pin on the OVMS. A voltage divider is needed as well as
>> +12V on OBD-Pin1 signals "ignition on".
> -- 
> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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