[Ovmsdev] Add +12V ignition detection in OVMS HW v3.3?

Mon Aug 10 02:46:49 HKT 2020

Mark already suggested you maybe can simply check the supply voltage.

If the car system always turns on the DC/DC converter when awake /
switched on / charging, and keeps the converter running exactly as long
as it is switched on / charging, that's totally sufficient.

The additional hardware solution may come to help if that is not the
case, or the voltage doesn't change far enough to be sure about the
source. For example if a car doesn't have a 12V battery and runs 12V
equipment from a stabilized DC converter, or if the DC converter
switches off when the 12V battery is full. Also be aware the 12V
measurement may need user calibration.

But as no other car developer joined this discussion it seems there
isn't actually any need for a switched 12V detection.

Regards,
Michael

Am 09.08.20 um 14:17 schrieb Soko:
>
> One more thought from a newbie to this issue which just came to my mind...
>
> Where is the added value of this expensive solution compared to just
> reading the 12V voltage. My eUp measures 12.6V when its shut down and
> 14.4V when its ready-to-drive/driving or charging.
>
> Soko
>
> On 03.08.2020 08:31, Mark Webb-Johnson wrote:
>> DB9 pin #1 is used for k-line. I guess it could be re-used for two
>> purposes (on an expansion card).
>>
>> That said, it would make the cabling a little tricky. The DB9 12V is
>> permanent. Having a 12v switched supply as well would presumably mean
>> a loose wire coming out of the cable? Seems easier to just make a
>> simple DA26 cable with just 1 pin connected to a loose wire (or other
>> wire outputs for relay, and general inputs, etc) - kind of why I was
>> thinking of making this a more sophisticated board.
>>
>> Regards, Mark.
>>
>>> On 3 Aug 2020, at 1:26 PM, Michael Balzer <dexter at expeedo.de
>>> <mailto:dexter at expeedo.de>> wrote:
>>>
>>> The re-certification requirement is a PITA for hardware evolution.
>>> But I'm ok with extending the K-line board, many OBD vehicles will
>>> still have K-line devices (even the Twizy's UCH and airbag modules
>>> are on K-line / KWP2000).
>>>
>>> Regarding the DB9, can't we use pin 1 (GEP_7) for this?
>>>
>>> Regards,
>>> Michael
>>>
>>>
>>> Am 03.08.20 um 04:21 schrieb Mark Webb-Johnson:
>>>> 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
>>>>> <mailto: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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>>>>
>>>>
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>>>
>>> -- 
>>> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
>>> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
>>> _______________________________________________
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>>
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-- 
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26

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