Feeler - Touchscreen OBC with Megasquirt CAN interface, extra sensors, outputs, etc.

[bsun260]

Thank you both for the speedy and helpful info. To clarify I did mean to refer to the OBC to the right of the radio.

I agree a test dash would be the best way to test fit and fab the internal support for servos and cables.

I do not have programming experience in the languages or protocols you mentioned above but I do have experience in VB, macros, HTML, etc. basic coding scripts. Would you think with some online learning this is something I could pick up quickly or better off hiring something like that out? I enjoy that type of stuff so I’d be down to learn. I’ll start researching arduino.

Would you guys be interested in updates here or should I start a new thread?

Thanks again!

[Panici]

Thank you both for the speedy and helpful info. To clarify I did mean to refer to the OBC to the right of the radio.

I agree a test dash would be the best way to test fit and fab the internal support for servos and cables.

I do not have programming experience in the languages or protocols you mentioned above but I do have experience in VB, macros, HTML, etc. basic coding scripts. Would you think with some online learning this is something I could pick up quickly or better off hiring something like that out? I enjoy that type of stuff so I’d be down to learn. I’ll start researching arduino.

Would you guys be interested in updates here or should I start a new thread?

Thanks again!

You'll be better off working at a microcontroller level like an arduino. A higher level PC based control will just add complexity.

Please start a new thread, I'm interested in following along!

[mikey.antonakakis]

Thank you both for the speedy and helpful info. To clarify I did mean to refer to the OBC to the right of the radio.

I agree a test dash would be the best way to test fit and fab the internal support for servos and cables.

I do not have programming experience in the languages or protocols you mentioned above but I do have experience in VB, macros, HTML, etc. basic coding scripts. Would you think with some online learning this is something I could pick up quickly or better off hiring something like that out? I enjoy that type of stuff so I’d be down to learn. I’ll start researching arduino.

Would you guys be interested in updates here or should I start a new thread?

Thanks again!

You can learn embedded programming relatively quickly - it's more low-level than you're used to, but you've already got a big head start, and there's a much more direct relationship between what you write and what actually happens on the hardware.

And yes, I'd like to keep this thread focused on this project, but I will keep an eye out for your new thread!

As for updates: I am trying to get a kit together for bbushree - things have been a little slow having moved this year (still haven't gotten my electronics workbench set up fully) and having a toddler, and now it's winter/snowy so my e30 is staying indoors... but my 3d printer is back up and running as of this week, I've got basically all the parts needed including the new PCB design. New PCB design means I need to do a little rewiring in my car if I want to use/test it in a real-world situation, and with aforementioned cold weather and now a non-heated garage the motivate to freeze my fingers has been low. Either way I'll be putting together a "v3.0" kit ASAP

[mikey.antonakakis]

Dropping in to say that I’m going to be doing some redesign on the touchscreen enclosure (the piece that fits in the OBC spot). Goal is to slim it down and improve the assembly with the touchscreen. The 2.8” screen that I use is a tight fit in the stock OBC opening, so there really isn’t much room to get a screw in the holes in the touchscreen PCB - the redesign will probably be a 2-piece deal where the two pieces clamp the screen in place or something. It’s finally not stupidly cold here for the first time in weeks so hopefully I can get it disassembled and redesigned this week.

Another update will also happen quite soon…

[mikey.antonakakis]

Okay, minor milestone reached! First (nearly) complete kit is ready to go. As mentioned in the previous post, I will be redesigning the enclosure for the touchscreen display to fit into the stock OBC location, but otherwise the kit is complete and includes:

• Main PCB with sealed DTM 2x12-pin connector
• Deutsch/TE Connectivity sealed enclosure for main PCB
• Teensy 4.0
• Nextion 2.8” Enhanced touchscreen display with short 4-pin harness
• 8ft, 24-pin harness (2x12-pin) with 20AWG TXL wire, and Deutsch DTM connectors (basically OEM-level wire and connectors)
• Solid-core wire for making jumper connections on PCB
• Micro-USB bulkhead cable, intended for mounting in the side of the Deutsch enclosure for more convenient reflashing of the Teensy and Nextion

The redesigned Nextion OBC enclosure will make the wiring a little more tidy and improve the retention of the display within the enclosure (as compared to the initial prototype installed in my own car).

[amarino]

Very cool!

[Panici]

Looking good Mikey!

[bradnic]

been lurking here for a while now.. cool project!! any updates?

[mikey.antonakakis]

been lurking here for a while now.. cool project!! any updates?

Not too many updates since last post, we’ve had a ton of snow this winter so e30 has been a little on the back burner. But PM me if you are interested in getting a kit, include some details on what you’re working on.

[mikey.antonakakis]

Mildly exciting updates coming soon... assuming it all works out after some brief testing.

[mikey.antonakakis]

Here's the main update: managed to at least physically fit a much larger touchscreen display in the stock OBC location - higher resolution, too: now 480x320 vs. 320x240. Also managed to match the stock plastic texture pretty well - the sheen is a little too glossy, but a light coat of flat back paint will get it close to perfect.,

Still need to test out the new PCBs and new display in my own car, will happen soon.

[amarino]

Looks awesome!

[mikey.antonakakis]

Installed and running! Here are a couple sample screens, there are 12+ visualizations. The OBC "buttons" are soft buttons that take you to the relevant gauge when pressed, and there are some tuning pages as well, such as wastegate control PID parameters, boost control modes, etc. I'll do a more detailed writeup and probably a video in the future.









Actual display subassembly, drop-in replacement for stock OBC (other than wiring). Yes, it clears the fan speed switch and AC/recirc switch (barely - the 3.5" screen's control PCB is larger than the "pocket" that the stock OBC fits into so it was very tricky getting this to go together).







Custom PCB running Teensy 4.0, for interfacing between CANbus, any desired sensor inputs, switchable outputs, touchscreen display, etc.
In my case I've configured the board via jumper wires to:

• run the display (power it, send data, receive user inputs)
• read 4 pressure sensors (two of which I've wired up low-pass filters in the built-in prototyping/breadboard area, cleans up noisy signals)
• run the stock econometer (low-side MOSFET switch built into board with 12V pullup circuit prototyped on the board)
• control two boost control solenoids (low-side MOSFET switches built into the board)
• trigger a relay that powers my VGT turbo's actuator (low-side MOSFET switch built into the board)
• read real time data from MS2 via CAN (built-in CAN transceiver, CAN controller is built into Teensy 4.0)
• send real time data to MS2 via CAN
• control VGT turbo via CAN
• read real time data from VGT turbo via CAN
• read turbo shaft speed sensor (VR sensor signal conditioner is built into the board)
• read EGT probe (amplifier built into the PCB so probe wires directly to it)

So, obviously this thing is doing a whole lot, so I need a lot of jumper wires. Looks more complicated than it is, though, my use-case is pretty far to the "complicated" end of the spectrum. That said, I still have 4 pins available on the bulkhead connectors for additional sensor inputs or control outputs if I need them - I might utilize them for additional pressure sensors, such as measuring pressure drop across my intercooler, pressure drop across air filter, and exhaust back pressure in downpipe.

I'm also considering designing an "add-on" board that would be dedicated to analog inputs, running a separate Teensy 4.0 and communicating to this one via CAN. Expanding like this would allow a whole lot more analog inputs, and I would include pressure transducers directly on the board so you "wire" in vacuum/pressure lines rather than locating pressure sensors throughout the engine bay and needing to run wires everywhere. This would also possibly include optional digitally-configurable low-pass/antialiasing filters in the signal paths to ensure clean signals for any use case. For example, I read my wastegate's dome pressure into a inner and outer PID control loop to get close-loop dome pressure boost control using onboard compressed air - due to the operating frequency of the solenoids that feed/vent the wastegate dome, there's a lot of oscillation in the signal sometimes - low-pass filtering this signal gives much better performance. Likewise with pre-turbo exhaust manifold pressure, it can be a pretty noisy signal due to the extremely transient nature of the pressure in the manifold, low-pass filter cleans up the signal so it's easier to understand what's going on.

[amarino]

That 13 button OBC screen is awesome retro look! An add-on board that can sit in the engine bay and communicate back over CAN would be cool as well.

Any options for stock ECUs and adding additional sensors to display on the screen (wideband O2, additional coolant temp, oil temp/pressure).

[mikey.antonakakis]

For now, PM me if you're interested. Things are still in a bit of a testing phase but I can get a kit out to you relatively quickly if you're interested. As such, I'd like to discuss your desired implementation to make sure it's a good fit for this stage of the project (the hardware you have, your project scope, and your programming skill level).

At some point there may be totally plug-and-play versions for common vehicle setups, but this is really intended as a moderately DIY, highly modular system that can be adapted to work for more than just e30+Megasquirt (like my use case). Think e30 + swapped engine with CAN (e.g. S52/S54, etc.), non-e30/BMW, and different locations and sizes of touchscreen (or no touchscreen at all). In exchange for that modularity and high level of adaptability comes some DIY. The closer you are to e30+Megasquirt the more I can help you with a nearly turnkey solution, and the simpler your project scope (e.g. just displaying gauges and not controlling anything) the easier it will be.