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Discussion Starter · #1 · (Edited)
This thread is for discussing any and all features for LiBCM's touch screen. No idea is too crazy!

For my R&D testing, I've purchased the $50 'enhanced' display, but my goal is to design the firmware to work on any 480x320 Nextion display (basic, discovery, or enhanced series). This display's viewable area is about the size of a credit card:

Once the Nextion firmware gets underway, I'll provide a Nextion 10' cable to anyone who wants one.

Timeline:
I don't expect to develop ANY Nextion features for several months. However, @Natalya expressed interest in possibly designing the Nextion firmware, hence I've started this thread as a public discussion for what we want the display to display.

Why Nextion?
I'm not committed to it... if you have other ideas, convince me why I should use them. Note that any display that will work with LiBCM must support all commands and graphics sent from a standard UART.
 

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Let me plug into the OBD2 so I can watch engine peramiters too 馃ぃ 馃ぃ 馃ぃ 馃ぃ 馃ぃ.
 

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The Nextion is cool but pricey and there is a lot of code to write.
It also does not come cased IIRC although you can buy/3d print enclosures.

A lot of people already have RCA component video capable head units.
E-Bay Reversing camera screens/mirrors are also very cheap.

Basic B&W video text/graphics can be generated by a $2 processor using serial data input.
The processor for that could even be incorporated onto the LiBCM main board with an RCA phono socket on board.

The we could just use a simplebutton/joystick serial encoder to send data to LIBCM or even a light pen LOL.. If LiBCM monitors the HLine then you could send simple serial commands via the OBDII port.

This all open source with docs/firmware. (I use it a lot)

 

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I think one of the selling points on this one was the touch-screen aspect, so you can update config parameters.
 
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Linsight Designer
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Discussion Starter · #5 ·
Thanks for all the feedback so far. Here's the part where I say 'no' to everything ;).

Let me plug into the OBD2 so I can watch engine peramiters too 馃ぃ 馃ぃ 馃ぃ 馃ぃ 馃ぃ.
It's beyond the scope of this project.

The Nextion is cool but pricey and there is a lot of code to write.
Considering our low volume, the $50 per-unit price is much less than the engineering effort to design something else. Assuming QTY100 LiBCM Displays are ever installed, that's just $5000 in Nextion COGs.

There isn't much code to write... the Nextion editor handles it pretty well on the screen side. On the LiBCM side, it's just a standard UART.

It also does not come cased IIRC although you can buy/3d print enclosures.
True. The $5 acrylic case I purchased along with the screen is good enough for now.

A lot of people already have RCA component video capable head units.
E-Bay Reversing camera screens/mirrors are also very cheap.

Basic B&W video text/graphics can be generated by a $2 processor using serial data input.
RCA component video isn't an ideal solution. It's an outdated technology and doesn't include the return channel for touch input.

The processor for that could even be incorporated onto the LiBCM main board with an RCA phono socket on board.
Nothing else is going to be incorporated onto the LiBCM PCB... it's full and finished and I don't want to rev it again. There's certainly not enough room for a gigantic RCA plug.

The we could just use a simplebutton/joystick serial encoder to send data to LIBCM or even a light pen LOL..
I've never liked joysticks. I much prefer touch screens.

If LiBCM monitors the HLine then you could send simple serial commands via the OBDII port.
LiBCM can either talk on the H-line or talk to LiDisplay (but not both). It's a shared UART.

This all open source with docs/firmware. (I use it a lot)

This doesn't allow the user interface I've envisioned for LiDisplay. I want full color support with graphics... not just text.
 

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I know this is herecy, but I like the 4x20 display, I just wish I could get it in red.

As for the touch display
-Being able to watch the voltage in a graph form in real time.
-A setting to force the pack fan to full tilt.
 
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Discussion Starter · #7 ·
I know this is herecy, but I like the 4x20 display, I just wish I could get it in red.
LiBCM will support the 4x20 display for the foreseeable future... possibly for years. It won't be difficult to drive both screens simultaneously.

As for the touch display
-Being able to watch the voltage in a graph form in real time.
-A setting to force the pack fan to full tilt.
You're talking about the entire pack voltage (not the cells), right? If so, that's an easy screen to add. Possibly display both IMA power and pack voltage at the same time?

Setting the fan speed to a higher value will be supported... LiBCM won't let you turn the fan off when it wants to be on. For maximum airflow, you'll even be able to run all four fans at full speed at the same time.
 

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Everybody has a phone. I would just do Bluetooth or Wifi to a phone. If you do Bluetooth Low Energy, your phone app can run on Android and IOS. You can also have opt-in data collection to Mudder Central for all kinds of stuff. Write the app in React Native or any number of other cross-platform environments.
 

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You could even distribute updates with a phone app. You could even sign them to ensure authenticity. However, for true authenticity you will need some means of secure boot for LiBCM.

On the other hand, a network connection back to the device would provide a path for the system to be attacked. So actually scratch the idea of any kind of network connection - bluetooth, wifi, whatever - because that's going to open up a whole 'nother can of worms.
 

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LiBCM will support the 4x20 display for the foreseeable future... possibly for years. It won't be difficult to drive both screens simultaneously.


You're talking about the entire pack voltage (not the cells), right? If so, that's an easy screen to add. Possibly display both IMA power and pack voltage at the same time?

Setting the fan speed to a higher value will be supported... LiBCM won't let you turn the fan off when it wants to be on. For maximum airflow, you'll even be able to run all four fans at full speed at the same time.
A. Sweet!
B. I was more talking about monitoring the highest and lowest voltage cells(at time of key on). But even just monitoring pack voltage and power would be cool to see on a graph.
C. Yea no, I definitely would never turn the pack fans off. I am always listening to music, so I have never heard the fans come on while driving. I'd rather run them full speed all the time so the pack is always(or at least most of the time) equal to cabin temp.
 

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I second Sean's phone idea. Certainly from a user perspective it would be nice. No wires and a nice color touch screen that you're already familiar with. But there may be technical reasons that I don't know about that make it unfeasible or too difficult.
 

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A phone/bluetooth/wifi/4g app would be good but that needs a tx/rx hardware (module) at the LIBCM end for a start.

Comms would have to have some sort of basic security or at the next Insight fest someone wandering around could do some tweaking of all the LiBCM systems in range!
 

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A phone/bluetooth/wifi/4g app would be good but that needs a tx/rx hardware (module) at the LIBCM end for a start.

Comms would have to have some sort of basic security or at the next Insight fest someone wandering around could do some tweaking of all the LiBCM systems in range!
-maliciously applies full assist to everyone that parks their car in gear-
 

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We already have a usb cable coming out of LiBCM. Couldn't we use a custom phone app with something like this:

No security concerns to worry about, from a BT perspective.
 
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I know this is herecy, but I like the 4x20 display, I just wish I could get it in red.
 

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Okay, regarding the phone app approach... what if it was display only? (Like the current 20x4 display.) Would that make it easier? It would certainly prevent evildoers from messing with your battery parameters. Do we really need to futz with parameters from a touch screen? The people that want to do that can still do it by editing config.h. I'd rather have a wireless display-only device than a wired touch screen display, if I had a choice. I like being able to see the voltage and stuff, but messing with parameters doesn't seem important.

Just throwing it out there.
 

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(edited for brevity)

An Arduino could be configured as an I2C client and parse the LCD data to obtain key variables without touching LiBCM code.
On another interface the Arduino presents a simulated OBD2 ECM and presents the data as custom PIDs.
This interface employs an OBD connector into which a common Bluetooth or Wifi OBD2 reader from Amazon is inserted.
A phone running Torque pairs with the Bluetooth/Wifi OBD2 reader, allowing customized display of data with zero custom Android or IOS code written.

This is something anyone can do, today. It would not be difficult to prototype, maybe an evening or weekend day to get it basically working, since code examples for both the Arduino I2C client and OBD2 ECU simulator can be found on Github, the Bluetooth OBD2 adapter can be found for < $20 on Amazon, and Torque Pro is $5 IIRC.
 

Linsight Designer
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Discussion Starter · #20 ·
From a hardware perspective, adding a bluetooth radio is trivially easy, and doesn't require any changes to the LiBCM PCB... I'd just use any of the various extant UART<->BLE converters, which are around $20. However, as @*sean* mentioned, adding that radio would require the entire LiBCM product to undergo FCC testing... that's an easy $15k I don't want to spend. That reason alone prevents me from jumping onboard the bluetooth train.

Another issue with wireless support is that now I have to support Android and iOS apps... for years and years. Given how often Apple and Android purge "low volume, low update" apps, I don't want to have to deal with that. The Torque app @*sean* mentioned doesn't have the flexibility I'm looking for... it's basically an OBDII scanner... I'm thinking bigger than standard query->response data presentation.

Also, there's the extensive work required to write and maintain two separate apps.

There's also the security aspect of adding a wireless connection to the battery management system. Certainly LiBCM's firmware could be written such that the wireless comms didn't allow users to change critical safety elements, but I don't want an IoT element to LiBCM... I actively avoid any and all IoT devices. I don't want to collect your data, and I don't want you to be ok with that.

For these reasons, I don't want to use a wireless phone for the display.

...

We already have a usb cable coming out of LiBCM. Couldn't we use a custom phone app with something like this:

No security concerns to worry about, from a BT perspective.
This could be made to work, but it would require users (that wish to use LiDisplay) to purchase a device that supports USB OTG... iPhones don't support this feature.

Honestly if we go this route, then a (possibly) simpler solution would be to use a raspberry pi (or equivalent), with a touch screen display. At that point, we'd basically have a complete linux box plugged into LiBCM... so the sky is the limit as far as what to do with the serial data coming from LiBCM.

We're going to need some kind of parameter editing lockout if the car is driving.
Which parameters are you thinking need lockout while driving?
I'm wanting the user to be able to switch modes on the fly (e.g. disable regen, disable assist, turn fans on, etc).

I was more talking about monitoring the highest and lowest voltage cells(at time of key on).
I showed a rough sketch of a couple cell level voltage displays in the video in post #1. Are you looking for some other way to display cell voltage data? If so, draw it on some paper and post a picture. I'm certainly interested in the actual content to display on whichever device we end up using with LiBCM.

Okay, regarding the phone app approach... what if it was display only? (Like the current 20x4 display.) Would that make it easier? It would certainly prevent evildoers from messing with your battery parameters. Do we really need to futz with parameters from a touch screen? The people that want to do that can still do it by editing config.h. I'd rather have a wireless display-only device than a wired touch screen display, if I had a choice. I like being able to see the voltage and stuff, but messing with parameters doesn't seem important.
One of the key features I want to add with LiDisplay is two way communication... so that the user can change settings on the fly. For example, when storing the car with the grid charger plugged in, you could plug in the grid charger, and then push the "long term storage" button (LiBCM would then maintain SoC at 50%). There are tons of features I want to add focused around user control.

@LowCarbon's one-way comm idea is neat; however it will need to be galvanically isolated and implemented so that there is no possible way of screwing up the installation or its use so that the user / installer / mechanic never sees 200VDC.
LiBCM's low voltage system is already 100% galvanically isolated from the HVDC bus. There is essentially zero risk that a properly installed LiBCM can pose any electrocution hazard to customers. Hold the LiBCM PCB up to a bright light and you'll see that all the low voltage signals are at least 3 mm** from any HVDC signal, and all HVDC signals are (at least) double-insulated from LVDC, using either photodiodes or transformer+capacitor galvanic isolation. LiBCM is designed to safely isolate HVDC overvoltages up to 2250 V, as defined in IEC-60950-1, using CTI class IIIA. To be clear, LiBCM is not UL certified, but I have designed the hardware to modern safety standards.

**250 Vrms working voltage in a class 2 pollution environment with a type IIIb (FR4) substrate requires at least 2.5 mm creepage; LiBCM has at least 3 mm minimum creepage from all HVDC circuitry. Note that LiBCM's conformal coating layer provides additional protection.

The problem with adding the extra display code to LiBCM functionality is that it really requires developing a unit test suite to make sure it doesn't do something to burn down a car.
We can make a sandbox for LiDisplay to play in. Only those features that we choose to expose to LiDisplay will be accessible by the UART. For example, we could only present "safe" options to the customer (e.g. "grid charge to 50%/75%/85%" (but not "110%").
 
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