# Leaf Instrument Displays



## Kevin Sharpe (Jul 4, 2011)

I'm investigating the possibility of reusing the Leaf instrument displays in my builds. I'm looking at options for repackaging the existing designs and emulating the functionality with new hardware 

The first step is a teardown of the 'combination meter'


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## Kevin Sharpe (Jul 4, 2011)

The 'Combination Meter' has a single, double-sided PCB, with four individual displays. The component density is low (i'll photograph the back side of the PCB at some point). Warning lights are individual LED's. Light pipes are used for the blue panel illumination.


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## Kevin Sharpe (Jul 4, 2011)

Like everything on the Leaf the tabs are brittle


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## Kevin Sharpe (Jul 4, 2011)

The 'Upper Meter' has a single, double-sided PCB, with one display. The component density is low. Warning lights and display backlight illumination are individual LED's.


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## Kevin Sharpe (Jul 4, 2011)

a few more details...


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## Kevin Sharpe (Jul 4, 2011)

main components...


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## jason_arnold (Jan 15, 2014)

I had some luck on that big 144-pin "D70F3423GJ(A)" microcontroller on the mainboard. It's a V850E/Dx-series MCU by Renesas Electronics Corporation:

- datasheet
- a boatload of other resources for the chip

It doesn't seem that MCU is readily available though, so if you wanted to roll your own custom PCB, you'd likely have to transplant it. I couldn't find a evaluation board to tinker with either, so it seems a lot of work to use it as is.

In case popping the individual displays off and faking the LEAF signals would be less work, I also got lucky with the LCD manufacturer: apparently a company by the name of Varitronix and they do a whole pile of automotive displays. 

Taking a closer look at the LEAF's cluster, I see a combination of graphic displays and segmented displays. They all look rather OEM/proprietary, so I wouldn't hold my breath on finding datasheets, but all the ribbon connectors are quite nicely exposed, so sniffing signals shouldn't be too much of a chore  As a bit of a Hail Mary, you could try to pull some part numbers off of them? We might be able to cross-reference them with some of the specsheets on the Varitronix website.

I must say, for the amount of tech in this cluster, the parts count is delightfully low! With a heap of elbow grease and a dab of luck, it would be awesome to get this mapped out to the point of rolling your own PCB to remix the arrangement as you see fit... then 3D print some custom gauge pods, laser-cut some clear acrylic and BOOM 

I'm kinda tempted to pick one up myself now to tinker with!


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## Cor (Sep 17, 2013)

Kevin Sharpe said:


> main components...


The upper display appears to have no processor.
The IC2810 is an 8-bits LED driver with I2C bus and the BCP56 are simple 80V 1A NPN transistors.
The 74A50G is an ultra-low-drop-out regulator 5.0V 400mA with 2% accuracy output. Full part nr NCV4274ADT50G


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## Cor (Sep 17, 2013)

jason_arnold said:


> I had some luck on that big 144-pin "D70F3423GJ(A)" microcontroller on the mainboard.
> It doesn't seem that MCU is readily available though, so if you wanted to roll your own custom PCB, you'd likely have to transplant it. I couldn't find a evaluation board to tinker with either, so it seems a lot of work to use it as is.


The small 8-pin SO chip above the processor looks to be a serial EEPROM. I bet that the identity of the cluster is stored there (as well as ODO and maybe a few other permanent bits of data, at least in the Prius the combination meter stores the ODOmeter reading - just apply 12V and it will tell you how far the vehicle went that it came out of...


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## eBIMMER (Feb 28, 2020)

Thanks for posting this. I'm actually going to eliminate the Combination Meter from my build, but have not been able to do it yet. The Leaf system will not shut down without the Combo Meter installed. Otherwise things work just fine without it.

It seems from your pictures I could probably strip the assembly down to a thin little assembly to minimize the volume it takes up and maybe slip it into the glove box. Is there any reason you can think of why that wouldn't work?

Thanks again!


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