Wednesday, June 28, 2006

Small Touch Screen LCD

How about a small touch-screen for the Mac Mini?
These touch-screens have been around for a while, traditionally used in car PCs with some creative modders adding them to their SFF PCs, and even being offered on some high-end HTPC cases like the Silverstone LC18. In the past these units were quite pricey, but recently they can be found on eBay and various online stores for around $200. The touchscreen interface makes it suitable for doing away with the mouse and its small size makes it an ideal display where space is tight; either acting as a second screen for a HTPC connected to a plasma/projector or as a screen for a second PC (media server, kitchen PC, etc).



There are many different brands and models on the market, I selected the Lilliput 7" widescreen model 629GL-70NP/C/T. It offered the highest native resolution 800 x 480 I could find for its size and also has an extensive set of touchscreen drivers including one for Mac OSX. As the manufacturer did not have any distributors in my country, they offered to ship to me directly for $209 plus a very reasonable $9 shipping cost. Actually the shipping cost was for two screens, I also purchased its larger 10.4" brother.

A front and back view of the 7" widescreen. The unit has a d-sub VGA input, 2 composite video inputs, and a stereo audio input. The touchscreen has a USB interface.









Its supplied accessories include connecting cables/dongles, stand with adhesive base, remote control, driver disk, and two power adaptors; one wall brick rated at input of 110-240v with an output of 12v 1500mA, and a cigarette lighter type car 12v adaptor with a small box which contains circuitry I believe to regulate the fluctuating car voltages.











And here is a look at the 10.4" model FA1042-NP/C/T. It's very similar to it's 7" brother, even uses the same wall power adaptor, however besides it's larger size, it has a 4:3 aspect ratio, higher native resolution of 800x600, a wall mount stand, and costs $40 more.






















Hooking it up to a PC was straightforward and touch screen drivers installed easily under Windows XP. With the Nvidia drivers, a range of resolutions were offered (using a 6800GT graphics card) however for the 7" I was unable to add a custom resolution of 800x480. The closest was 840x480 or 720x480, but maybe Powerstrip would fare better. In anycase the standard resolutions 800x600 and 1024x768 worked fine, but of course the image was stretched on the widescreen; in order to keep the correct aspect ratio of 15:9, 1280x768 also worked but everything appeared very small.

Here you can see the 10.4" (4:3) set at 800x600 on the left, the 7" (15:9) set at 720x480 on the right, and a Dell 24" (15:9) set at 1920x1200 in the background.










TOUCHSCREEN INTERFACE
The touchscreen interface worked better than I expected. Navigating through Windows was no trouble whether using the supplied stylus or just my finger (although not recommended for people with large fingers). Even for writing it's not so bad (photo), however sufficient pressure must be applied otherwise the screen will falsely detect the pen/finger has been lifted up.
In addition to the 4 point and more detailed 25 point calibration, there are several settings in the driver that can be optimized depending on how you plan to use the screen including multi-monitor support. To access the right click, it can be set so that when the cursor is held stationary at one point (around 3-4 seconds) it will act as a right click. This works fine, except of course when you're scrolling through a large window and have the cursor held down on the scroll button for 3-4 seconds.

One problem that I found only on the 10.4" model was there is an approx 1.5mm deadzone on the left of the screen. There's a clear transition where the touch screen ends, it's as though it wasn't aligned properly during installation or the touchscreen is just too small for the LCD (click to enlarge the photo). This gap is not large and the driver can be set so the cursor automatically extends out to reach this area, but the problem is it won't be able to track your stylus if you run it along this edge.

IMAGE QUALITY
I already expected that touchscreens would have reduced brightness/contrast because the touchscreen element is not completely transparent, but was very disappointed with the 7" screen. The screen is very speckled, like there are two layers of low quality screen savers stuck on top of the LCD. Or kind of like someone forgot to peel of the layer of protective plastic that sometimes ship with screens. The 10.4" (and other LCDs to a lesser degree) also have some speckle, but it's barely noticable unlike the coarse and dense grain on the 7". This makes text blurry and difficult to read, and smooth tones look blotchy. Trying to capture the look of a display in a digital photo is always difficult, but these images give some rough ideas what I'm talking about (click photo to enlarge).













After searching on the internet, I found this forum posting on MP3car.com as well as on computeractive.co.uk, both mentioning this problem. It seems the manufacturer has added an anti-glare coating/layer? (these touchscreens are quite reflective which creates problems for car use under bright sunlight). It seems the older 619 model which has a more reflective, but sharper, clearer and brighter screen more suitable for indoor use.
That's really unfortunate as otherwise the screen image looks quite decent. Even set at 1280x768 characters appear smooth and legible on the 7" screen if you look past the speckle. The colors are pleasing to the eye and color balance can be tweaked by the monitors OSD.
For the viewing angle sweet spot, this is quite narrow; the color/contrast will change with a slight head movement even though the image remains visible through a decently wider range.

Here is the 7" next to a Phillips 7" LCD digital photo frame (no touchscreen) and provides comparable image quality. On images where there is no smooth tone, the speckling of the touchscreen is not that noticable.



And here are all three monitors. Certainly the Dell 24" still looks the best, but both touchscreens are certainly acceptable.
I actually spent have a day running office apps on the 10.4" and it was quite usable albeit the small size of 800x600. Unlike the 7" however, it seems there is no/poor anti-aliasing or smoothing as any resolution above it's native 800x600 looks bad.



CONTROLS
The LCD controls are located in a row across the bottom of the frame. On the 7", once the power is plugged in, the POWER switch lights up red. After the unit is turned on, this changes to green. The other buttons only light up when they are pressed. The OSD is relatively clear and usable as far as screen OSD goes. The left arrow provides a nice shortcut for AUTO ADJUST and the right arrow to step through various brightness settings (changing from day to night).







NOISE AND HEAT
Well the 10.4" does seem to have an internal fan, however it is very quiet and from the front can barely be heard. It runs warm, but not hot. The 7" however seems to run quite hot, both the front and back of the panel. In a 29C ambient room, the front of the panel got hot enough that it was uncomfortable keeping my finger on it for too long. It seems the 7" does not have a fan, so no noise can be heard when it's operating. However when the PC is shut down and the monitor goes into standby, a soft high pitched hum can be heard. This only goes away when a VGA signal is supplied again or the screen is turned off.
Both units do have built in speakers. Certainly not hi-fidelity, but not completely horrible either. The 7" speaker sounds similar to the Mac Mini's internal speaker and the 10.4" a little better. The 7" screen however will only pass through the sound when a video connection is selected and not when the PC/VGA connection is selected. The 10.4" passes through sound even in PC mode.

MAC OS X
The Mac Mini's DVI-Dsub adaptor had no problem working with these screens, however I was unable to get it to detect the touchscreen even after installing the OS X drivers. However when I boot up my Mini under Windows XP (exact same connections) the touchscreen works fine. I suspect the drivers were written for the G4 version of OSX and not compatible with the newer Intel version. I contacted the manufacturer and will see if I get any reply, in the meantime I'll try to see if it'll work on my G4 Mini.
For the 7" screen, my Intel Mini only gave three resolution options, 800x600, 1280x768 and 1280x1024.

FIRST THOUGHTS
Although the 7" is not ideal because of it's very speckled/grainy display, it could still be a decent interface for my HTPC. I originally thought of affixing this to the front of an Antec NSK2400 case, connected as a second display, and powering it off the PSUs 12v rail. This would eliminate the need for a mouse and allow for other operations to be performed without disturbing the video playing on the main screen. The high heat level has me a little concerned, instead maybe I will try mounting it on top. The high pitched sound in standby is also unfortunate, but as a second screen making use of the power button may not be so bad.
The 10.4" will probably be paired with the Mac Mini which is currently connected to my TV in the bedroom. Unfortunately the Mini doesn't support dual displays, although with the DVI-Video adaptor you can get both S-Video and Composite video out simulatenously (one to the TV and one to the 10" screen). Unfortunately Composite video quality is much worse than VGA/Dsub but I'll have to see if it's acceptable on the 10.4". If it does work out with my Mini, I'll probably look into painting the frame silver or white (although the glossy black and white combo on my new keyboard doesn't look too bad).

For those interested, there are more discussions regarding these touchscreens and some very nice modding/installation work on www.mp3car.com forums including a poster who installed a Mac Mini and a 7" touchscreen into his Mini Cooper.

Goto Touchscreens Update1


2 Comments:

At 8/11/2006 10:58 AM, Anonymous Anonymous said...

Any luck on Drivers for the Intel Mac, or with testing the display with a PPC mac? I was thinking of using this display as a gps display for my boat.

I've got an old ibook g3 that I'd like to bolt down somewhere (boats tend to thrash around a bit in bad weather) and then mount the 7" vga at the helm.

Just curious if you had any follow up...

 
At 8/12/2006 1:10 PM, Blogger mmstac said...

Hi, I did manage to get the Intel OS X beta drivers for the touchscreen from www.egalax.com.tw. You can read more about it on my Touchscreens Update 1 post from July 3 (you can select this from my Index or Home). If you are using and older version of Mac OS, you might want to double-check there are drivers to support it on Lilliput or Egalax websites.

 

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