my Zeitronix ZT-2 display

jwmelvin

jwmelvin

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I have started working on a display for the Zeitronix ZT-2 wideband O2 sensor and data system. Thanks to Dave Dozier (@DDozier) for suggesting the Zeitronix; Zeitronix is a great company for sharing their serial specifications. It would have been impossible otherwise. While Zeitronix sells a number of pretty neat displays, including a fancy touchscreen that has been consistently out of stock, I like to tinker with electronics, and have been interested in playing with a little OLED screen for a while, so I figured this would be a good project.

It uses:

I have just gotten it to the point of receiving data mostly reliably from the ZT-2. In my initial setup, I wanted to display all of the parameters that I am able to measure (I don't have a full sensor complement on the ZT-2): AFR, MAP, RPM, TPS. My plan is to integrate the display where the clock currently resides; it will require a new housing but I think it should be possible. It may be my first use for 3d printing.

Here is a shaky and blurry video that I took from my windshield mount:
<iframe width="853" height="480" src="//www.youtube.com/embed/IbQ9fd_YFxs?rel=0" frameborder="0" allowfullscreen=""></iframe>

From the bottom to the top,



  • At top is a bar graph showing boost, following the same color coding as for the numeric MAP display below.
  • Numeric displays show Manifold Air Pressure (MAP) and Air:Fuel Ratio (AFR).
    • MAP is red under vacuum conditions (no boost), yellow when entering boost, and then green above 4 psi (max is about 6 psi with this supercharger setup).
    • AFR is red when not under boost, white when AFR is below a desired value based on boost, and blue if above that value. I used a simple set of conditions where under a certain boost (currently set at 4 psi), the AFR must be under a certain value (set at 13 currently). For MAP above that boost threshold, the AFR must drop linearly (currently set with a slope of -0.5, so AFR must be under 12 at full boost of 6 psi).
  • The fat bar near the bottom is the tachometer, which changes color to indicate shift point (green > red > blue).
  • On bottom is a bar graph showing throttle position.


All the color-changing, moving elements are pretty confusing, and the display is very small. I need to think about the best information to display and the best way to display it. But this is a test setup to try out a few things. Figuring out the best way to draw bar graphs, changing colors, and even the numeric values took some time. There are still a couple of weird issues with reading the data consistently, as you can see in a flash of the display where MAP has a problem (around 0:12 in the video).

I don't think there is any need for MAP unless under boost, so the numeric display for that can go away. TPS is similar: it's not really something I want displayed. I will probably change the tachometer to only show up from 7,000-8,000 rpm, as a shift light (or may bring back the LED-strip shift light I had in my last car, as it was in a better location at the base of the steering wheel and very bright). So that leaves AFR and the boost gauge. I may do AFR with a bar graph too, as reading numbers isn't necessarily useful.

I do have a separate, very bright 4-digit alphanumeric display (linked above) that I am considering adding, which could display AFR only when under boost, for example. I also have to think about how to mount the OLED in a way so that it's shadowed from the sun, as that will be required for readability. Fun project though and I appreciate any ideas you may have.

-Jason
 
Thanks for the pictures. That's almost exactly what I had in mind for the mounting. I hear you on the display brightness. I have yet to see how the OLED works out when mounted there, but I suspect I will want the segmented-LED display too because it is so bright.
 
If you figure out a way to brighten the display up, please let me know. Good luck on you project.
 
[MENTION=25419]Valhalla[/MENTION], I'd love some tips on how to approach a housing to replace the clock module. I don't have a spare clock module, and I'm not yet convinced it's worth the cost of a replacement just to get the shell, so I will be starting from scratch.

Here is a picture and video of the revised display. The photo was taken in a parking garage, but give some idea of the relative brightness compared to the clock/CCU. I think it will be pretty good, and it's nice that I can make the color whatever I want, to match or contrast with the rest of the displays.

zeitronixOLEDv0.2.jpg

<iframe width="853" height="480" src="//www.youtube.com/embed/s3g3SFha8CE?rel=0" frameborder="0" allowfullscreen></iframe>
 
Jason - I got a used and not working extra clock module from Shawn in Tampa. I think he gave it to me and all I had to do was pay for postage. I know there are others out there and perhaps someone might view this thread and donate one to you for this project.

I only used the front frame and sides so that the unit would not blow out of the dash when I hit the go pedal! From there I used some left over plastic, glue and a little bondo to shape. Took a bit of time to get it where I want it but I'm still happy with how it works. I have the "naked" gauge and remote the control board back inside the opening. I also mounted the Zietronix alarm in the air vent and it is loud and a red light flashes. This alarm is totally programmable and I have it set to go of at 7500 rpm's and also if the turbos overboost. A very nice option. Here are the links to these two items;

http://www.zeitronix.com/Products/LCD/LCD.shtml
http://www.zeitronix.com/Products/zavt/zavt.shtml

If you want to go another option, you might be able to take some really good measurements and construct this with a 3D printer. I'm not familiar with what you can and cannot make with these.

On a side note, is there anyway to make my display brighter? Thanks.
 
Valhalla said:
On a side note, is there anyway to make my display brighter? Thanks.
Click to expand...

That display looks like a pretty typical 20x2 negative character LCD. It's white on black so one option is to find one with a brighter backlight. Another option is to change to one with an RGB backlight. I buy a lot of stuff from Adafruit, which has them but not in a 20x2, only in a 20x4 and 16x2. At least that way you could tune the color perfectly. Of course, this way you would have to add a circuit to drive the backlight, although you could still use the processing portion of the Zeitronix display. I believe LCD character displays tend to almost all use the same controller chip (HD44780).

My approach was the OLED screen, both for it's color and for readability and small size. We will see how it looks once mounted. I'm still on the lookout for the best display. From what I read, transflective LCD may work well in sunlight. There are also some other technologies that look promising if color is not a requirement, like this one, although it's small like my OLED.

Edit: it looks like the negative character LCD displays may be more difficult to view in sunlight, so a positive display may work better. They don't look nearly as nice though, IMO.
 
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Those are some interesting displays but the one you show in the original post is pretty incredible for colors, bar graphs and legibility of text. The one thing I don't care for is that it's so damn small and would be impossible to read or monitor four applications in real time while driving. I think I would be most happy with;
- All four of my existing read outs (Fuel Pressure, AFR, EGT and Boost)
- A brighter display
- The ability to match existing OEM instrumentation color while in normal operating references
- The ability to have the values change color due to + or - reference values. For instance; Blue when no boost, OEM orange from 0-4lbs and red for above 4lbs.
This would look very OEMish and the color coding would be an instant alert even if you couldn't study the active readout while under motion. Just my $.02.
 
I suggested those LCD character displays as something close to a direct replacement to your existing display. I very much prefer the OLED I'm using but I hear what you are saying about its size. There is a slightly taller OLED (128x128), which might work, especially with two or three side-by-side.

For larger displays, it seems like graphical LCD is the only option.

This 3.5" ezLCD-313 seems like it might be good if the refresh rate can be high enough. It would certainly be very easy to program, as the controller provides a serial interface. It does not have a bright backlight (80 nits) but that shouldn't be a factor when lit from the front, since it's transflective. I'm tempted to try it out since it looks so easy to use.

This 2.2" LCD might work and is smaller, but has a backlight of 200 nits, which is not enough to show up in sunlight (from what I read, that requires about 800+ nits, like these).

I think this Sharp 3.7" LCD (model LS037V7DW05) might be the very best. It is transflective and seems to offer their best indoor/outdoor performance and includes a resistive touchscreen. Also available without a touchscreen (model LS037V7DW06), which also has brighter backlighting. But it would require some proper development to pair a controller to the raw display. It generally has been my experience that drivers are available for most of the commonly used controller chips; that's how I am using my OLED. But I don't know anything about a controller appropriate for the Sharp displays.

Edit: It looks like 4D Systems has some interesting options including a slightly larger, 160x128 OLED with a controller on it. I wish I had started with that instead. They have a few different LCDs but none immediately jumps out as great in the daylight.
 
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I moved my little OLED screen to the clock location and sent my clock module to be 3D scanned, so I can model and print a replacement.

The weather was nice today so I had the top off and took a few pictures under various lighting conditions to show how it looks compared to the CCU display. Under all lighting conditions it's at least as bright. I'm thinking for my final display, I will use two of these OLED screens or two of the 160x128 screens I linked above, maybe still in combination with the LED segment display. Still considering options.

These shots were all taken within about 5 minutes of each other. Around 6:30 pm, first with light coming in the windshield, behind the display, then in the shade but with light from behind, and then with light directly on the console at a low, partially sideways angle:
OLED_lighting.jpg
 
Thank you. I'm definitely planning to show the time too. The microcontroller I use has a real-time clock built in, just need to solder in the crystal oscillator and add a battery backup. That's one reason I think I may want two side-by-side screens in the final design. Plus, some people, or I in the future, may want to display more than just AFR and MAP.
 
Those displays certainly seem to be as bright as the OEM controls. A question for you is the LCD's for the this dimmable? I mean are they on a circuit with the rest of the dash lights so that you could dim them during night driving?
 
If someone could get this down to a direct replacement for the clock I think you would be on to something.
Otherwise I will have to wait for this. http://www.germid.cn/video_32.html

This will be able to display gages, Bluetooth, nav, play music, record drag racing, rear view monitoring ,display email and search the internet.
It should release in the next few weeks.
Ken
 
ken sampson said:
If someone could get this down to a direct replacement for the clock I think you would be on to something.
Otherwise I will have to wait for this. http://www.germid.cn/video_32.html

This will be able to display gages, Bluetooth, nav, play music, record drag racing, rear view monitoring ,display email and search the internet.
It should release in the next few weeks.
Ken
Click to expand...

That is quite a piece. Very nice. But I don't think it will be able to monitor AFR, Boost, etc.
 
Valhalla said:
Those displays certainly seem to be as bright as the OEM controls. A question for you is the LCD's for the this dimmable? I mean are they on a circuit with the rest of the dash lights so that you could dim them during night driving?
Click to expand...

Yes since the clock connector receives the lights-on signal, it would be easy to tie into that and dim the display. But I was thinking that I might put a light sensor in to have it dim based on ambient light.
 
Hey [MENTION=25419]Valhalla[/MENTION] I made some progress. My brother's friend, who is a master designer, drew up a housing that I had 3D printed by Shapeways. I am just doing some test fitting and will have to work on adapting my code to the new displays.
B57C123C-EDFB-4397-8EDA-D9090B3236C1_zpsoshipz7f.jpg
 
[MENTION=28830]jwmelvin[/MENTION] that looks real nice. Mine is holding up well and sits so stealth like. Show us the finished product when you get it done.
 

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