MPGuino screen dimensions
 

I want to install a MPGuino into a factory console, like the over head console used in the GM S-series trucks and suvs:

http://s-series.org/albums/album44/t..._fuel_used.jpg

My question is, what is the width & height of the MPGuino screen seen here?

http://spiffie.org/bw/_media/kits:mp...kmpg.jpg?w=600

I need the screen size before junkyard hunting a console. Thanks :thumbup:

It is standard size 16x2 LCD screen.
I searched "16x2 screen" in ebay and first result had these dimensions:
Dimensions of screen: 65mm x 14mm (2.5” x 0.5”)
Dimensions of unit: 82mm x 37mm (3.2” x 1.4”)

Maybe difference would be 1-2mm in different screens.

You should research the datasheet for the screen you want. Here is the low-power lcd that comes with the prebuilt:

http://www.newhavendisplay.com/specs...FSPG-FBW-L.pdf

These two match the same pin-out as the one in the prebuilt:

16x2 Character LCD (RED) - NHD-0216K1Z-FSR-GBW [NHD-0216K1Z-FSR-GBW] - $14.90 : Fundamental Logic WebStore, Electronic Kits and Components

16x2 Character LCD (RED) - NHD-0216K1Z-NSR-FBW [NHD-0216K1Z-NSR-FBW] - $14.90 : Fundamental Logic WebStore, Electronic Kits and Components

Same manufacturer too. If you have any experience with the different color LCD screens, which would be the most visible through a tinted lens, the red background, black lettering; or the black background red lettering?

Ideally, I'd like to use the black background/red lettering (2nd link), so that only the red lettering shows through the lens like the stock display, but I don't know if it'd be visible enough.

I know that in the end that it'll come down to trial and error, but I'm just curious if you've messed with red LCD screens before.

I like the transflective ones for good visibility in all light conditions. I've tried transmissive ones and they were more challenging to read well in daylight.

I don't like blue for night driving but green/yellow or lower frequencies seem fine. Red should be perfect for night (except that it is a warning/alarm color).

The screen dimensions should be in the datasheets for those LCDs per your original question. http://www.newhavendisplay.com/specs...-FSR-GBW-L.pdf

The other consideration I can think of is the backlight driver is meant for 20ma on the prebuilt, you will have to reduce the series resistor accordingly if you need it to be brighter and if you are not using a low power backlight with a current prebuilt board. The two you listed are low power (20ma) but something to consider if you are still shopping.

And speaking of ergonomics, It is far more practical to put it on the dash/in front of the instrument cluster, if you are planning on referencing it a lot. Helps keep your eyes on the road, less places to scan visually.

Red is since the all of the interior is lit in red at night:
http://www.youtube.com/watch?v=ci7UpfpQGG

I don't like a mix of colors at night... I'm already having to resist ripping out the headunit in this car (while it has great features and sounds awesome) for it's blue lighting.

I had this exact console when we had our '98 GMC Jimmy, and being just above the rear view, it was easy to check. For my project, it'll go into my Formula, with it's lower roof line the display is even closer to my line of sight. I habitually check mirrors so for me it's a good place.

Another thought I had on this console was to flip it upside down, and trim off the garage door buttons/lights/sunroof switch half of it, and shape the screen half to sit on top of the dash, just above the A/C vents. Again, going for a factory look inside the car.

Also, I have just a working knowledge of building circuits, so let me make sure I've got what you sad. The series of resisters for the 20ma screens can't be made any brighter, but if I found a display with a higher rating, I could make a lower resistance series and bump up it's brightness? Or can the 20ma screens deal with a bit less resistance?

I think after looking at the kit more, I feel good about soldering it up. The offset cost of between it and the prebuilt would cover a red screen.

OLED maybe?
OLED 16x2 character display

VFD is also a potential option, though more expensive still.

I played with vfd, I don't recommend it, too much power and readability wasn't good in direct sunlight (whereas transflective LCD is perfectly readable in direct sunlight).

http://ecomodder.com/forum/showthrea...play-8071.html

oled is interesting, but may also suffer in direct sunlight.

Yeah, I think they're demonstrating it's performance on that product page. If you look at the first image, the lighting is very diffuse like you would have in an office environment. The second image has sharp shadows and the display text looks weaker... I think that pic was taken outdoors in direct sunlight. [edit]Heh, yeah... It says "Direct sunlight" in the caption. -_-[/edit]
The reason VFD works so poorly in direct sunlight is that the phosphor pixels are white, so the light emitted by active pixels gets lost in the reflected light under strong lighting conditions. As suggested above and as is the case in many applications, a dark lens should help block that light. These OLED modules appear to have such a filtering lens built into the module.

It sounds like you have to up the OLED power consumption if you add a filter too, and oled is still twice as much as lcd. transflective FTW IMHO, use the sunlight when it is available, use the backlight when it isn't. Low power, Low cost, great readibility in all conditions.

30mA sounds perfectly reasonable to me. Yes, it's more expensive. If cost is your primary concern, an LCD is your best option. But if you start considering other qualities such as nighttime readability, transflective displays can be less than desirable.

transflective has problems with nighttime readability?!? I've never had any problem.

It's the black text on a bright background.
The reason it takes so long for your eyes to adapt to dark conditions is level of neurotransmitters in your eyes. When you sit in the dark, the nerves aren't firing so the neurotransmitters build up, making your eyes more sensitive to light - better able to see in the dark. This is also why going from a dark room to daylight hurts your eyes - your eyes' heightened sensitivity makes everything seem much brighter.
Anyway, if you look at something significantly brighter than your surroundings, it depletes the neurotransmitters in that area of your retina, leaving an area of reduced sensitivity. This phenomena is commonly known as a sun spot, but can be triggered by not only the sun, but other relatively bright lights such as a camera flash. The key is that brightness is relative. Shining a cheap flashlight in somebody's eyes at night can leave them with a sun spot, while they may not even notice that the light is switched on during the day time.
Getting back to the topic at hand, looking at your LCD backlight isn't going to instantly give you a sun spot in your vision. It will however leave an area of reduced sensitivity. The brighter it is and longer you look at it, the greater the reduction. This means that when you look back up at the dark nighttime road, you won't be able to see as well in that key center area of your vision.
Reducing the display's bright area reduces the impact on your nighttime vision. The simplest way to do that is to use a transmissive type display... Lit text on a black background.
Transmissive LCDs have daytime readability issues due to their design and VFDs have power consumption issues. OLED displays have neither of those issues, and therefor should an the ideal solution.

OLEDs DO have daytime problems I thought. Have you first hand experience with an oled display in daylight? Is this a solution looking for a problem?

I keep the transflective backlight (and the dash lights) on its lowest setting, really haven't had a problem. It doesn't need to be bright to be readable in the dark.
Edit, and readibility wise, dark on light is most ergonomic.

http://www.youtube.com/watch?v=JVYI4...tailpage#t=41s

The images on the above product listing seem to indicate otherwise. No, I have not tried the display for my self, though I'm probably going to order a Newhaven graphic model here momentarily, so I'll let you know.
Keep in mind that video is of a touch screen (touch panels, and multiple layers in general, cause optical issues) phone (limited battery power) from 2 years ago (plenty of time for development on a relatively new technology) using a full color screen - a lower resolution monochrome display means you have bigger, brighter pixels and less wasted space between them compared to a high res full color screen.

Right, but we aren't talking about e-readers here, we're talking about automotive instrumentation. How many instrument clusters have you seen that have a dark-on-light pattern at night?

If you are willing to test it I will certainly listen.

One thing that wasn't clear was if that oled can work with a 4 wire interface.

My head unit is OLED. I use it on the simplest setting, no animated visuals. It's good day and night, so that the BG is black and the lettering is lit, it's the LED buttons that is too bright. Good in daylight too, better than my old LCD head unit screen.

Play time. ^_^
http://dl.dropbox.com/u/9882625/Newh...splay_0244.jpg

Cool, going graphical.

Careful though, that thing can suck up to 400ma, and needs 2.8v. With 14v supply an inexpensive linear regulator would need to dissipate almost 5 watts.

Yeah, I see the voltage requirement, though the spec sheet says max 400 microamps (0.4 mA) for logic, and a maximum of 66mA draw (53 mA nominal) by the display panel with all segments on. That's only about 3/4 of a watt across the regulator at 14 volts. Still noteworthy, but not really demanding any dedicated hardware.

But yeah... It looks like I'm going to have to do logic level conversion to interface with an arduino. Crap. On the other hand, my Seeduino mega has a switch to run in 3.3V mode, which the display spec sheet says it should tolerate. I guess I'll give that a try for the moment.
On topic, the character display versions require a 5V supply, so this shouldn't be an issue on an MPGuino.

oops, yah you should prolly plan on 66MILLI amps for 3/4 of a watt in the regulator.

The polarizing filter is a mixed blessing, one of the few drawbacks of lcd is that they don't play well with polarized sunglasses, but of course the lcd wouldn't work without being polarized. LEDs are another story.