Matrix Orbital Corp

Hi everybody,

I am in the process of building a high-end HTPC (mostly audio-based), but I'm quite new to LCD/VFD displays.

I want my Audio PC to work just like a CD player, with :
- 6 buttons (On-standby (PC), On-off (display), I<<, Play/Pause, >>I, Eject)
- A LCD/VFD display that will show real-time iTunes or foobar2000 information.

The problem is that I'd like a very large display in order to show artist / song / album / time elapsed (bargraph) without having to scroll horizontally in case of long titles. So I guess a 4x40 display would be fine.

This doesn't seem to let me much choice, since I only see two 4x40 displays : LK404-25 and MOP-AL404C-BYFY (or maybe a graphic display that would be long enough ? ).

Just FYI, the Audio PC would look approximately like this :



Here are my questions :
1/ Could you please make me understand the differences between LK404-25 and MOP-AL404C-BYFY ?
2/ What display would be best for my project ? (maybe you think that a graphic display would be better)
3/ I see that a VFD display is expected to arrive one day (VK404-25). What about it ?
4/ More specifically, what about graphic VFDs ? Will you sell them one day ?
5/ (most important question) How can I connect my 4 display-related buttons (On-off (display), I<<, Play/Pause, >>I) to the display, so that the display transmits the button information to the PC when a button is pressed ? (like if a keyboard key had been pressed for instance - that would be great). Is there some guide about it that I can read ?

Thanks in advance for your help.

Jose

Jose Hidalgo wrote:Hi everybody,
Here are my questions :
1/ Could you please make me understand the differences between LK404-25 and MOP-AL404C-BYFY ?
2/ What display would be best for my project ? (maybe you think that a graphic display would be better)
3/ I see that a VFD display is expected to arrive one day (VK404-25). What about it ?
4/ More specifically, what about graphic VFDs ? Will you sell them one day ?
5/ (most important question) How can I connect my 4 display-related buttons (On-off (display), I<<, Play/Pause, >>I) to the display, so that the display transmits the button information to the PC when a button is pressed ? (like if a keyboard key had been pressed for instance - that would be great). Is there some guide about it that I can read ?

Hi Jose, Glad to see your into the HTPC side of things. I got into it about 3 months ago. It's a great addition to your entertainment system!

To asnwer your questions:
1. The LK404-25 is serial based interfaced display. This display can accept RS232, TTL, or I2C communication. This make it very easy to talk to the display simply by sending any form of programming language to it. The MOP-AL404C-BYFY is a parallel driven display and has none of these abilities. All engineering and programming has to be done on your end. The parallel series is typically for companies or hobbiests who plan on doing all of their own engineering. Does that help?

2. I think, at your size requirements and desires, that a Graphic Display would be a MUCH better choice. Not only can you have a large display, but the benifits of graphical over alphanumeric are well worth it. You can then make the font as big or small as you want, upload your own bitmaps in seconds, or have detailed bargraphs or animations. I would recommend taking a look at the GLK24064-25 as it seems to fit your size requirements.

3. Unfortunately I cannot provide any further news on the VK404-25, but you can expect it in the new year some time.

4. Graphic VFD's are on the agenda, again, I have no news on the release of these, as other projects are currently of higher importance. Keep in mind though, custom displays may be ordered, but of course with large minimum quantity requirements

5. As for the keypad, all the information on setting up the keypad will be available int he manual for each display which can be found at our support site http://www.matrixorbital.ca. As long as you have a Matrix style Keypad, you can configure the display to react however you wish for each button press. The GLK24064-25 has a keypad pinout on the display for this purpose.

If you have any further questions, please don't hesitate to ask.

Regards,

Hi Nick, thanks a lot for your reply.

1. Understood. It will be a serial based display then.

2. The GLK24064-25 is a tempting model (although quite more expensive than the LK404-25 ). I'll take that into consideration. Sure, a graphic display would be a better choice (and I can choose the display colors too). On the other hand, the GLK24064's display length is a bit shorter than LK404-25's (132 vs. 148mm), so if we consider the same character width between the two displays (this is just an example of course), the GLK24064 would rather look like a 36 character per line display instead of 40. But it's nonetheless a great display. Hmm, decisions, decisions...

3. Now for the keypad. This is the main problem for me. I just can't purchase a matrix style keypad (where would I put it ? that would look awful within my project !). So I need to interface my own 5 buttons located under the display (see above pic), and each button of course has its own wiring. Is there a simple way of doing this ? Do I need a special cable or an intermediate board ? Or is it just impossible ?

The final purpose is that, when I press one of the 5 buttons ("play" for instance), the display transmits the key information just like if a standard PC keyboard key had been pressed. Then, with a software like Girder for example, I'll be able to control just about any music player software (foobar, iTunes, etc.) to react to that keypress. I hope I'm clear enough. A lot of PC manufacturers do integrate front panel multimedia buttons, but I just don't know how they do that.

4. I have looked for the GLK24064-25 user manual at www.matrixorbital.ca , but all I've found is the technical manual. Is there a downloadable user manual somewhere ? Thanks in advance.

Best regards.

Hi Jose,

The matrix style keypad header on our displays are designed to generate a keypress when a row pin is shorted with a column pin. This means you would have to have a wire coming from a row pin from the display, and another wire coming from a column pin, and then when the button is pressed the wires become connected.

The keypad connector is located on the back of the display and has 12 pins, the first and the last pins are ground and then the pin out is as follows:

Rows Columns
12345 12345
GxxxxxoooooG
..|........|
..|........|
..|........|
...\....../
....\.../
..[Button]

YES ! Thank you so much Jon, that's exactly what I needed to know, and this means a giant leap for my project

This project will take several months, but I promise I'll keep you informed in this topic. Thanks again.

Oh, maybe one last question : what is the name of your software that handles the keypad and allows to map the keypad's buttons to PC keyboard equivalents ?
e.g. key 1 ---> "A", key 2 ---> "CTRL + Right arrow", etc.