Megasquirt 2 Sensor Monitoring

[taaron]

So I'm starting to plan on my dash and getting everything in order. I'd like to run a purely tablet driven dash. Most of the sensors I need are accessible via Raspberry Pi running Tuner Studio hooked up to my Megasquirt 2 (v 3.57). Is there anyway to also get readings like, oil pressure, fuel level, gps speed, through to tuner studio? 

[softopz]

You can get GPS speed via the tablet sensor, Oil pressure would need a sensor to MS2 which is doable.

[taaron]

I've got the original oil pressure sending unit. Any chance that would work? I"m also just looking at the wiring diagram and cannot figure out where it'd even go

[Gollum]

You're fairly limited on extra inputs with MS2. I'm running MS3X and still finding myself wishing for more ADC inputs. That said, there's two spare ADC on the MS2 3.0/3.57 setup on JS4/5. These would work for extra inputs like oil pressure and fuel level, but a typical resistance value like the OEM fuel sender or oil pressure will require a pull up resistor from TPSRev 5V, and the resistance curve. You only get one custom sensor curve, otherwise your fuel level/oil pressure would have to use the same curve of another sensor, like MAP, CLT, MAT, EGO. Since the nissan oil pressure likely doesn't use the same temp/resistance curve, I'm opting for a linear pressure sensor which allows trivial calibration, and you can run a custom linear calibration on each custom input.

 

That said, mine are in the mail. Should have them installed this weekend hopefully. These are the units I went with.

 

https://www.ebay.com/itm/202353428547

 

Keep in mind for oil pressure you'll need a 1/8 BSPT to NPT adapter.

 

What I ordered:

https://www.amazon.com/gp/product/B00NWZ3TUI

 

 

As an aside, this seems to be a common topic and the answer people wish existed was "use CAN bus for extra IO". Except I can't find a single working example of MS2 getting extra INPUTS from CAN bus. I can find lots of gauge products with extra IO that operate on canbus that claim megasquirt compatibility, but when you read their user docs they say the extra inputs are for MS3+ only.

 

Now, if you were running a pure CAN Bus based display (haven't looked into viable CAN->Android dash solutions yet, honestly hadn't crossed my mind until just now) then a separate GPIO->CAN controller could broadcast data long with MS2 and you could get all that data available to the dash. A simple adruino would fit that bill nicely, and give you piles of extra IO to work with. You just wouldn't be able to do anything with it inside the MS2 ECU, which also means you need logging at the dash side, or separately on the arduino itself.

[Gollum]

Seems there's at least a couple people who went for an android based CAN bus dash solution, which I find interesting considering all the dedicated race dash devices appear to be MCU based, not MPU based (think arduino not raspberry, no real OS just compiled code that direct acts upon the hardware).

 

http://www.valvers.com/open-hardware/projects/android-dash/

(pretty stale)

 

https://blog.arduino.cc/2016/05/31/maker-installs-an-android-tablet-in-his-cars-dashboard/

(less stale)

 

And I think I knew this in the back of my mind somewhere, but RealDash is likely the smoothest bet to adding an extra IO box and using with with MS2 data for a dash:

 

http://realdash.net/manuals/realdash_can.php

 

But of course, you're running an Pi already, and want to use it's ADC built in. Sadly, I haven't found any way to grab non-Megasquirt data into tunerstudio dashboards. I'm sure it's a potential feature Phil could write in considering the work already done to grab other sensor data in shadowdash, but again, I haven't see success of what you're looking for.

 

This is also why I've been so on the fence about what to do about dash hardware/app. I've decided for my own project for that now I'll be using shadowdash on my main phone and deal with the limitations of MS3X inputs.