E81/E87 Hands Free Arduino/KCANBus/BT solution

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VPCAPTAIN
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by VPCAPTAIN »

Hi DaIceMan just a progress update. Got it all assembled (used my 3D printer and a couple of designs off Thingiverse.com, to make up a couple of plastic enclosures and although a tight squeeze they look good and should protect the finished components when encased in hot glue to minimise the solder joints vibrating apart.
Have added an OBD2 connection as well to allow me to test the can bus steering inputs work without hard wiring the rear of the radio for the testing phase. I discovered my chosen Bluetooth board was drawing too much current along with the can bus board from the 5v output on the arduino pro mini so I’ve added a separate dc to dc buck converter ( only £2 at Amazon ) and this safely converts 12v to a steady 5v 3a output so more than enough current for the 3 boards and it’s protected from spikes etc when the alternator outputs 14v or more. The hardest part so far is once I soldered all the connections when I bent and manoeuvred the wires to fit into the enclosure more than one or two wires broke at the solder joint hence deciding to use hot glue to give the solder Joints some mechanical strength. That seems to have solved that issue but will need to fully test in case of any broken joints once in car. Thanks again for all the brilliant pictures / write up / you tube videos showing your idea.

Last edited by VPCAPTAIN on Tue Apr 20, 2021 4:25 pm, edited 1 time in total.
DaIceMan
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by DaIceMan »

Hi, glad to hear you sorted everything out. You can upload pics on imgur.com any size and link them here, the account creation is free. Else if you'd like to attach pics here in this forum you can use a free image editor called IRFANVIEW (https://www.irfanview.com/) which can resize your pics as you wish.

The buck converter option is fine - alternatively even a typical 7805 with a couple of decoupling caps would do (1Amp TO-220 version) as the current drawn by everything is really minimal, but the switching buck converter is certainly more efficient. I didn't quite get where you tapped into the K-CAN bus if you didn't get it from behind the radio.

Cheers

Luke
VPCAPTAIN
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by VPCAPTAIN »

Hi Luke thanks for the quick reply and I’ll certainly look up imgur.com and IRFANVIEW to get some pics uploaded. to save time I quickly wired up a spare OBD2 connector ( the same as where you plug in a code scanner ) which in theory allows me to connect the CANBUS MCP2515 into the car and then using a usb serial converter I can check all the steering push button commands are received. This was just to test and once I’m happy they work ( no broken solder joints ) I’ll connect into the rear of the radio wiring. I measured the current draw on each pcb board and although they were all less than 100mA the Bluetooth board wouldn’t boot correctly hence opting for the buck converter, but appreciate the help. The buck is tiny at 11mm x 10mm and at the price was so cheap. Will keep this post updated with pics etc when I get to install Thanks Rob
DaIceMan
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by DaIceMan »

Aha got it - yeah once you sort everything out you can piggy back the K-can from the radio. Boxes are a nice touch and they should fit under the radio area; I have everything double taped on one single board (the BT module). I also have that white BT you have somewhere (I got a few), without the infrared receiver - it's the same chip just with another board layout (it has an aux input jack).
VPCAPTAIN
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by VPCAPTAIN »

Just wish there was a way of removing that annoying voice that comes through the speakers when connecting Bluetooth 🤣 👍
VPCAPTAIN
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by VPCAPTAIN »

Just an update couldn’t get the steering button commands to work with my first board - ive rechecked all connections and they are intact, it’s possibly the white Bluetooth board uses a different button detection technique or a possibly faulty canbus MCP2515 board, ( ive got 5 to try ), waiting on a different Bluetooth board to try again. May just tape the boards as you did as it allows easier access to the FTDI serial interface. Will keep you posted.
DaIceMan
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by DaIceMan »

Did you use a laptop connected to the arduino and monitor the serial monitor output? This way you can debug and check what happens when you press the buttons.
VPCAPTAIN
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Re: E81/E87 Hands Free Arduino/KCANBus/BT solution

Post by VPCAPTAIN »

Thanks for the advice I couldn’t get a reliable connection between the ftdi serial interface and the arduino due to the cables in the way - I’ll strip the boards from the boxes and test again and report back - it certainly displayed a canbus output once a second on the bench. 👍
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