DIY Mini-Dash LCD Gauges Update
 

Just wanted to give an update on the Bluetooth and CAN bus gauges...We now have a much smaller working "mule" development module.

This version shows real time engine coolant temperature, engine oil temperature, engine oil pressure and air/fuel ratio of bank 1.

The next version will have multiple screens to show more data. Items like differential oil temp*, real time tire pressures, automatic transmission fluid temperature, and current gear.

* The differential oil temp uses na engine coolant temperature sensor from a Nissan Sentra, with a custom adapter that we developed.

Sub'd!

Wait, so CAN bus has oil pressure?

That would be nice, but it doesn't.

I have a 150 psi pressure sensor in the place of the pressure switch and that is connected to our "bluetooth sensor server". The oil pressure is received by the mini-dash and displayed.

The bluetooth sensor server can support up to 8 sensors, so there is lots of room for expansion if needed.

The main reason we decided to use bluetooth was so that wires don't have to be run wires from the engine bay, through the firewall to the interior.

The only wiring that needs to be done is ignition and ground... and those are VERY easy to find under the hood :)

Ok thanks. Just checking I didn’t miss something.

Understood... I may not of been clear as a few people have asked about that.

What about boost? :tup:

Boost should be possible.

Off the top of my head I see a few different ways this could be done. Stand alone MAP sensor connecting to the bluetooth server sensor, tap into factory MAP sensor, or if you are tuned, there might be a way to get that off the CAN bus.

Tuned on Ecutek by Seb at Specialty Z. Any way to get the AF to read off an aftermarket O2 sensor instead of the factory sensors?

It depends on the AFR gauge/controller being used.
For example, AEM's X-Series controllers have a 0-5 volt output that is proportional to AFR and they also have a CAN bus output of AFR.
(https://www.aemelectronics.com/produ...ntroller-gauge)

Tell me what gauge/controller do you have and I will look into it.

Also, I have verified that boost levels can also be read using OBD Service $01 (live data)


Thanks for the excellent questions and keep them comng :)

I use the AEM 30-0310 X Series controller with a Speedhut gauge. Good to hear about boost readings

Hey Frank, since I'm on a roll here, what about ethanol content? I'm currently using the Zeitronix ECA-2

Yes, the ECA-2 has a 5 volt output that can be used as an input (Ethanol % = 20 * Voltage)

Also, I could get the ethanol content and fuel temp from a typical GM flex-fuel sensor. They have an output of 50 Hz (0% ethanol) to 150Hz, 100% ethanol.
That is easy for a microcontroller to measure and calculate.

With that said, I haven't done this, so I would need to do some testing.

Next Question :)

One last question, when are you going to have this available so I can get rid of all my other gauges and the big wad of wiring buried behind my cubby panel? :rofl2:

Your setup looks nice!

As for when, the only answer I have is sometime in the spring.
COVID supply chain issues forced me to do a complete hardware redesign and since there were no car meets, it was difficult to get the raw CAN bus data.

But it is all coming together :)

Thank you Frank, it was a fun project.
It sure would be nice to consolidate everything into one small panel though. Keep the updates coming

Looking forward to the finished product. I have something similar, yet not as extensive, in my Jeep that has saved me big-$$$ repairs in the past.

I really hope you never get rid of that digital clock "gauge"! :tiphat:

So there are apps out there like torque app. That can show gauges based on Bluetooth data from Bluetooth odbii devices like the odblink Mx+

I have the brainiac kit and mx+ and was planning to do this eventually. Also apps like Harry’s lap timer can read this data as well as part of your lap logs iirc.

Do you have any plans to make your Bluetooth server compatible with these apps?
Not sure if there’s some kind of standard format for these things or if every app has been programmed to translate the data properly. But being able to add any custom sensor to an android app via your server would be pretty amazing.

Excellent question!
Apps like Torque Pro or OBDFusion get their data from the ECU by asking for it using OBD Mode $01 (aka live data) via the ELM327 OBD device.

As fas as I know, those apps can only be connected to 1 bluetooth device at a time, so it can only get bluetooth data from the OBD port or the bluetooth sensor server.

The original design goal is plug and play gauges that start up in less than 1 second without user intervention. (don't have to start an app)
For now, I don't have any plans to create an OBD type device that will work with OBD type apps. I think there are many excellent apps available now.
However, there is this VERY nice Android/iOS App called "Real Dash". (RealDash)

In a nutshell, it uses data from multiple sources to drive/animate some great looking gauges.
Over the next few days, I will look into what would be required to send the bluetooth sensor server's data and data from the CAN bus to it.
That could be a good option for someone who wants hi-resolution gauges on any Android device.

Thanks for the question!

Ah yeah, definitely looks like they (realdash) are more open to different data sources than torque app. It would be neat if your bluetooth server sent data over BT via the AIM 5-byte they mention in the FAQ. Then you could use your gauge client with any AIM 5-byte server. (like DashBox - SP Leinonen) or use your client with any compatible display (could it integrate with AIM dashes maybe? or would that be wired not BT)

Either way really awesome project.

^^^
Well... I went down another rabbit hole and spent the morning reading up on Real Dash and looking at example code. It looks to be very flexible as everything can be defined by XML files. Nice!

To get the 350/370 OBD live data options (about 40+ depending on year) is very easy, to add the CAN bus data into the Real Dash app doesn't look too difficult.

However, I have more research to do to understand how I can add in the analog sensors (pressure & temp) from the bluetooth sensor server. There are a few options that I will look into, but it isn't a high priority for right now.

I was about to suggest that for you Real Dash with your MX+ would give you just about everything you may want (except for oil pressure) BUT all the Real Dash layouts are horizontal and your tablet is vertical. Too bad :(

I'm letting my imagination run away with me. Like what would a low cost easy to integrate sensor server look like that runs on bluetooth. You have all the parts already built for it just need a generic data transport that lots of "clients" support.

The other ones out that that do similar things are very expensive and usually part of a larger ecosystem like Motec. And don't have bluetooth. I think you could get them to a tablet via the MX+ and custom PID settings in the apps tho. But honestly I haven't looked at it.

Is your project going to be open source? I would be interested in poking around the code if so.

Just to be clear, the bluetooth sensor server is just for the analog sensors (temperature and pressure) that are in the engine bay, eliminating the need to bring wires through the firewall.

The bluetooth data is then merged with the CAN bus and OBD live data, which is displayed on the LCD display.
The only generic (or well documented) client I am aware of is RealDash and maybe RaceChrono. (overlays gauges on track video)

Down the road I will spend some time to see how I can all the data into those above items. The good news is, that anything can be changed to fit another format.


With the OBD system, it can only have 1 master (MX+) and one slave (ECU) as the same CAN bus addressing IDs are used for the scantool and ECU. I can't think of a way to add data to the MX+.

For right now, it isn't open source. I have a few thousands hours in development over the past 2 years and I need to get some kind of return.
Down the road I would love to let people more talented than me to see what they can do. -OR- I may just give up and get a real job :)