What kind of cable/connector/hardware would be needed
to play with these things... Currently I only have the DUE and
the LEAF...
Somehow I envision that I something CHademo-connector like
to actually get readings from the car?
There are 3 groups of things to access, monitor, or log.
1. The handshake pins (3 or 4)
2. The CAN pins (CH and CL)
3. The two HV Power pins (PP and PM), Mucho Quidado, CAUTION
4. The Ground pin.
Not recommended, but possible...
Access is possible by very carefully making "connections"
to the wires or pins on the back side of the QC connector, or a bit
further down the wiring harness. In any case, please consider
that you would be modifying an expensive "toy".
We MUCH prefer making a Logging Adapter for the
QC Plug-Socket interface, so that neither the vehicle
nor the Charger needs to be modified.
The biggest help would be to locate really compatible
female HV pins for such an adapter, which we could
then 3D print.
We could install and connect the pins, tap the wires
and design a good tap circuit. Then, one could attach
a logging box, which would log both the measurements
and the CAN traffic via a USB virtual Comm Port to a PC,
or even log to an SD card.
We have all these pieces working now, on the Mbed,
Due, and AVR-CAN. However, no one uP's code
includes them all, at the moment. One needs the
low and high voltage interface circuitry, the CAN
"listening" transceiver, the USB / Comm Port, a
suitably high-speed SD card interface, and just
a bit of a user interface.
I have the Very small Mbed with USB logging,
CAN transceivers, a 2x6 LCD display, a couple of
buttons for user interaction, and a SD card on
a host-USB port. It is the most compact, but lacks
the interface circuitry. It was intended to provide
stand-alone logging of two CAN buses, and even
black-box type operation.
We have two versions of AVR-CAN code, one used
in the GID-Meter, which includes a CAN interface
and a Serial logging port that uses a Serial-to-USB-Adapter
cable to get the logging data to the PC. No SD card.
The other version includes a hand-wired interface board
to make the measurements, and is now used as
the controller for our experimental non-isolated
mini-QC device, which we are in the process of
documenting. Of course, we STRONGLY advise
against experimenting with non-isolated charging
of the QC type vehices.
With the Due, which is much larger physically, the
User Interface (UI) has gotten a lot more attention,
using a color TFT touch screen display, which is now
being programmed to speak Val-Serial Commands
to a Val-capable charger, and handle the Responses.
Logging via the Due's Native USB Port seems to work well,
and adding logging to the SD card slot that is on the
display board (or to the one on the display shield board)
is not expected to be too difficult.
If you have a Due, and one of the CTE TFT touch screen
(with font chip) displays that I "support" with my Sketch,
you are welcome to try my current Sketch, which presently
has about 6000 lines of code in approximately 8 files,
and requires at least 3 modified libraries, and several
other libraries that are not included in the Arduino IDE
package. It was working with the IDE "beta" version
1.5.4r2, but I just recently changed to using the just-
released version 1.5.5, where I have not seen any differences.
With the Due, others have wired up CAN transceivers
and other external circuitry, I expect, but I have not
yet tried my just-started prototype sheld, which presently
just contains on Transceiver chip and some resistors.
I intend that it will become the control interface from the
mini-QC charger, and control, if not actually interface to,
the vehicle's QC Port, to actually facilitate the mini-QC
charging process.
Since the input pins of the Due are only capable of
handling 3.3 volts, something like a 5:1 divider is usually
sufficient for the 4 handshake pins, and the CAN pins
would go directly to a suitable 3.3v CAN transceiver chip.
The HV pins might need like a 100:1 ratio, since the PP
pin would typically go at least 205 volts above ground.
However, the HV might not be perfectly balanced,
and the experimental mini-QC candidate might
put out over 600 volts, so a 200:1 ratio is probably wiser.
Keep in mind that the HV-plus is normally above ground,
and the HV-minus is usually below ground, but that is not
always true. In some circumstances, they might both
be positive, or both negative.
Using some sort of opto-isolation between these signals
and the Due is likewise also wise. Quite high value resistors,
perhaps 20 megohms, might be suitable for tapping
into the HV lines without upsetting the vehicle's
HV leakage tests. Also, if you touch anything exposed,
you want the experience to be safe, not "shocking".
More details on the interface circuitry later.
Cherrs, Gary