This one (see attachment) does most everything including keyscanning of a keypad.

Edit: to get back on topic. YES! I am desperate to get an empeg mounted in my truck. At a guess I might need 8-12ft of remotness.

PS if a custom housing is needed to house the remoted display. I can design it and get it made.

Well, as some of you may remember this is something I did about two years ago... and then got out of college, got a job, other priorities, and more or less disappeared. I'm probably never going to have time to improve this, but it's been good enough that I've used it in my car of all that time without being annoyed enough to change it. So if other people are still interested in it, you might as well start where I left off...

Source, and docs on the various VFDs that I have: http://applesolutions.com/Empeg/remote/

Pictures of it getting into my car: http://gallery.applesolutions.com/v/vincent/hardware/Empeg/Trunk+Mount/

The software was written over, oh, maybe a weekend; There's lots of room for optimization in the drawing. The main ugly bit is that the Empeg writes out the boot log to the serial during boot; Since my display doesn't run at 115.2k, it comes out as garbled junk. It's mainly for the 3900 (specifically the 256x64D one), but it looks like I started working on a 7100 too because the command set is almost the same. The k610a is rather different, and the 800 that you're linking too looks different too, but you can just change the implementations of the drawing calls to send the right commands.

For input, I found a neat Grayhill joystick that has the 7 empeg actions (up/down/left/right, knob+/-/push) all on one knob. A Basic stamp and a couple transistors and gates convert it's output into serial character presses that are sent to another app running on the empeg. It gets unresponsive when the player is particularly busy, kinda lame. The rest of the board in the pictures is a switching 12->5vdc transformer to power everything.. the display is just connected straight to the empeg's serial line.

I'll be glad to help wherever I can if you have any questions.. I'll try to check the forum, but probably best to email me: [my first name] at godaddy dot com

--
Vincent

Thanks! I'm going to look through this. Why is the serial connection so slow in your implementation? Is this a hardware limitation of your design? How could this be corrected/avoided?

Here's the question I have:

If the remote display is driven by the serial connection, how is it possible to also have buttons which send signals on the same serial connection? Why doesn't the display driver hardware monopolize the serial connection?

Thanks again. I'm definitely going to try to build one of these things. If anybody who knows how to hack the kernel is interested, maybe we can do this together.

Jim

The VFD I chose (GU256X64D-3900, because it's slightly under DIN-sized and -shaped, and has exactly twice the res of the Empeg in each direction) has a max speed of 38,400bps. If you want faster, pick a different display.. the 7000s are 115.2kbps, although as far as I remember it won't really work that fast because it starts reporting itself as busy and ignoring you if you're using the speed to do bitmap drawing. Some models (3900 included) have parallel input too, so you could theoretically use a parallel<->serial converter to drive it at 115.2 or 230.4. Drawing speed wasn't particularly important to me, aside from being an interesting optimization problem. I don't need visuals when I'm driving, and most of them look lousy in 1-bit 'color' anyway.

The display uses only the serial output, and the joystick uses only the input. There's no conflict. Some of the VFD models can send data back to you, but they don't tell you anything particularly useful.

You don't need to hack the kernel to make it work, although it would be helpful for a variety of reasons (suppress the serial output on boot, increased priority to update the display, etc).

I've decided to revisit this idea as I now have some spare time to do so. I was thinking perhaps of level shifting the signals at 12 volts and then back down to 3 volts at the other end for the display. I will see what I can come up with.

Stu

If I were to do something on this these days, I'd just buy a low-end Gumstix board and attach a cheap LCD to the Gumstix's built-in LCD interface.

This would allow a variety of possible connection methods, including serial at up to 800kb/s (the empeg would limit that to less), ethernet, and bluetooth.

And with a real Linux computer (the Gumstix) controlling the LCD, it could do grayscale/colour and should handle complex visuals just fine. Not to mention all of those extra I/O pins and interfaces for other empeg add-ons to take advantage of.

Cheers

Interesting...I've been looking at new cars, none of which will easily accept an empeg. I am at the point where I'll likely permanently or semi-permanently mount one of my spare empegs instead of hacking the dash apart. If I could extend the display to mount on the dash or a sun visor, that would be fantastic. Consider me very interested in seeing this happen.

I'm still gathering ideas. I believe it will employ video buffers for the high speed signals.

Stu