Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

Here is thread in the HTPC forum dealing with a very cheap (<$20) large vacuum fluorescent display (VFD) that can interface with a computer/Tivo using a single serial line and a single 5v power source.

http://www.avsforum.com/avs-vb/show...threadid=131974

There is a PDF document available which details the full command set of this display. There is also an application called LCDC which runs under Linux that can drive the particular display being discussed.

Since I'm not a Tivo expert I'm wondering how difficult it would be to use/modify the Tivoweb scripts to provide a data file that could be used by LCDC for displaying things like current channel, time, date, station ID, current position in playback stream, etc...

Last edited by JoeFloyd on 04-11-2002 at 07:16 PM

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Registered: Nov 2001
Location: NYC, USA
Posts: 443

The "serial" port on the Tivo Series I only has 3 pins - RX,TX, and GND. I'm pretty sure a VFD controller requires more than that (hardware flow control, if nothing else). No one's managed to do much of anything with a Series II Tivo (yet), so the USB port there won't be much help.

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

These displays only need one signal line. The TX pin of the COM port is connected to the display and that's pretty much it.

Set the port to 9600,N,81 (also supports 19200, as well as, a common parallel interface used by LCDs) and let her rip. Here is some VB code from another the [H]ardforum board that shows how simple it is to control this device.


MSComm1.CommPort = 1
MSComm1.Settings = "9600,N,8,1"
MSComm1.InputLen = 0
MSComm1.PortOpen = True
MSComm1.Output = Chr(&HE)
MSComm1.Output = Chr(&H15)
MSComm1.Output = Chr(&H19) & Chr(&H30) & Chr(&HFF) & Chr(&H7)
MSComm1.Output = " 12345678901234567890AaBbCcDdEeFfGgHhIiJj"


http://www.hardforum.com/showthread...15&pagenumber=6

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

Here are a few pictures of this thing in action.


These are also take from the other web forum listed above

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Registered: Apr 2001
Location: edge of tomorrow
Posts: 233

Hacking up the tcl scripts to stream the data over serial is pretty trivial. I'm just curious why you'd be close enough to your TiVo to read the display and yet not have the TV on to see what it's actually doing (still a cool idea though).

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

This thing is pretty big. Each character is about 9.2mm high by 6.4mm wide. The total size of the display is 7.75" x 2.58"

Some things that might be displayed:
Current channel
Current station ID (WJLA, WNBC, TLC, etc.)
Current time
Current Program title
Current Program description (scrolling)

While watching a recorded program:
Channel recorded from
Channel station ID
Program length
Elapsed time into program

Tivo Status:
Time to next scheduled recording
Time to next database update
Alert of new messages

It's also possible to program custom graphics using the dot matrix addressing of each character. So there could be VFD animations. A dancing Tivo for example.

Here is an image of the display next to a smaller display. Both are using Katakana character set.

http://www.villagephotos.com/pubimage.asp?id_=200117

Last edited by JoeFloyd on 04-11-2002 at 09:47 PM

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Registered: Dec 2001
Location: Athens, GA, USA
Posts: 24

I can see where having something as simple as the contents of /proc/therm on there would be quite handy. I pulled out my sick dtivo yesterday and turned it on, and forgot to plug the fan back in. When I checked, it was at 60C. After reconnecting the fan, it dropped back to 48C. Glad I caught it in time.

This thing looks rather neat. Hrmm... Might have to get one to play around with.

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Registered: Oct 1999
Location: Maricopa County Maximum Security Correctional Facility For Men, State Farm Road Number 31, Tempe, Arizona
Posts: 4413

What about building a client for LCDProc "server" and running both on the TiVo?

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Francesco
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Registered: May 2002
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Joe - I agree this was be a fantastic new feature - especially if it could be added to TiVoWeb... I might have a go at doing something....is anybody else interested?

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Registered: Apr 2002
Location: Harleysville, PA
Posts: 2

I was waiting till I built the housing for the displays and could get a decent picture to post, but, since the topic has come up again...



I am using two displays, the one on the left is being run off my linux box and, in addition to displaying the date and time, shows caller id infomation gathered from a modem on the linux box.

The display on the right is run from my Sony standalone Tivo. It updates once a minute and diplays the current channel, station id, time into program, program length, and program name.

I've attached the code (which is based on the onlive.tcl code) - I have yet to add any comments.

Use the code at your own risk ... I make no claim that it will not destroy your tivo.

It's been running on mine for the past month or so. The only caveat is that you cannot just kill the process if you want to stop or restart it -- there is a good chance that your tivo will reboot. Therefore, you have to "touch /tmp/vfd.stop" and wait for it to exit normally. Remove /tmp/vfd.stop and then you can restart the script.

Attachment: vfd.txt
This has been downloaded 353 time(s).

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Registered: Oct 1999
Location: Maricopa County Maximum Security Correctional Facility For Men, State Farm Road Number 31, Tempe, Arizona
Posts: 4413

...And??? Any progress, demark???

I've been holding off doing the TiVo case mods until one of you guys does all the scripting dirty-work for me!

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Francesco
Your services might be as useful as a barber's shop on the steps of the guillotine.

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Registered: Oct 2001
Location:
Posts: 39

Closed captions are a wonderful thing, but when sometimes they block the action. Having them on an external monitor would be excellent!

Might have to download that new sed binary to massage tivovbi's output, but it seems like it'd certainly be doable!

And only $20!

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

I would like to report that VFD.TXT does work under 3.0 Not that I know which version of the Tivo software it was designed to be used with. Just rename it to vfd.tcl and run it like any other script.

It will reboot your machine if you run the script from the prompt without detaching if from the shell. Well, that is if you break execution to get your prompt back.

Also, when you create the /tmp/vfd.stop file it can take up to 60 seconds before the script terminates.

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Registered: Oct 1999
Location: Maricopa County Maximum Security Correctional Facility For Men, State Farm Road Number 31, Tempe, Arizona
Posts: 4413

Ok for those of us less-than-skilled at hacking, but absolutely eager to try it all out, how about a simple step-by-step to get it working?

Specifically (because I'm dense), do I just place it in /var/hack/bin? How do I make it executable? What other guidelines can you or demark give? I have a VFD on order from BG...

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Francesco
Your services might be as useful as a barber's shop on the steps of the guillotine.

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

First off, I'm not a TCL/TK person and will only be able to tell you what I needed to do in order to get this to work. I assume you have hacked the Tivo to include the common UNIX utilities.

The VFD.txt file should be renamed to VFD.tcl just so you know that its a script. Copy this file to your hack directory, but I don't think that it really matters just as long as you have write permissions in the directory you're copying the file to. You may need to set execute permissions for the VFD.tcl file. You can do this using chmod with the appropriate permissions. I chose to set chmod 777, but that's because I'm lazy and didn't want to figure out what is the absolute minimum permissions needed to run this script.

To run the script from a bash prompt just type

/var/hack/vdt.tcl &

If you copied the file to some other directory, change the path as needed. Be sure to use "&" at the end of the command so that the script will detach from the current shell and run on it's own. If you forget to use & and break the script execution you'll get a nice cold reboot.

In order to stop the script you should use the method described in the post above. It may take up to 60 seconds before the script exits.

It seems pretty simple to modify this script to update more frequently, but I'm not sure how that will affect Tivo performance.

You can check that everything is working by connecting the Tvio serial cable to a PC with a NULL MODEM adapter. Set HyperTerminal to 9600 baud , 8 bits, No parity, 1 stop bit , No flow control. If the script runs correctly, you'll see a few control characters followed by the program information in ASCII.

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

I added the following command

/var/hack/vfd.tcl &

to to the end of the /etc/rc.d/rc.sysinit file

This will execute the script each time the Tivo boots. This should not be done if you use the serial port to log into the Tivo. If you have an ethernet installed in Tivo then it shouldn't be a big deal to tie up the serial port.

In order to edit the /etc/rc.d/rc.sysint you will need to remout the root partition with read/write access. You do that with the following command.

mount -o rw,remount /

After you've made the changes to add the new command, save the file and then you MUST remount the root partition as read only.

mount -o ro,remount /

You can then reboot your Tivo and have the VFD script run automatically.


Also, I have a question for demark or for anyone familiar with tcl and Tivo. What is the minimum time that can be used in the tcl "after" command. I've tried 1000 milliseconds all the way up to 60000 ms and it seems that the Tivo current channel info is not updated very often. Or perhaps the after command is not behaving as I would expect. Also, is there an event trigger that can be used to inform the script that a channel change has occurred?

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Registered: Oct 1999
Location: Maricopa County Maximum Security Correctional Facility For Men, State Farm Road Number 31, Tempe, Arizona
Posts: 4413

Hi, Joe,

Thanks for the info (basic for others, but makes things alot more clear for me).

That's what I was going to ask (about editing rc.sysinit); I have ro & rw "automated" so this should be straightforward. Cant wait to try it out! I've already Dremelled the chassis and moved the IR board. Now I need to shape a piece of gray Lucite to the curve of the front panel before I cut it!

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Francesco
Your services might be as useful as a barber's shop on the steps of the guillotine.

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Registered: Jul 2002
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Will the script above work on a DirectTivo? I for some reason bought 3 of those VFDs and never did get around to using one.

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Registered: Apr 2000
Location: Fairfax, VA, USA
Posts: 10

It seems that the VFD.txt script is very similar to the screen.tcl script found in TivoWeb. If TivoWeb works on a DirectTV Tivo, then the above script should work also.

I'm still trying to learn TCL well enough to make changes to the script that will speed up it's response to channel changes, show current playing program if it was recorded, time, etc....

From what I can remember, this VFD has hardware scrolling so there isn't much of a need to spend a lot of processor time updating the display.

It might be worth writing a simple binary app to improve performance if I knew the mechanism used to get data from the Tivo data base. The TCL script makes refrenence to a dbobj (data base object?) which I assume is a common Tivo TCL object shared between all scripts, but I don't really know.

I guess I'll search the forum for hints....

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Registered: Oct 1999
Location: Maricopa County Maximum Security Correctional Facility For Men, State Farm Road Number 31, Tempe, Arizona
Posts: 4413

OK, finally got around to wiring it all together (no biggie, though I keep reminding myself I can't solder for beans).

Works amazingly well! Of course, I never finished the acrylic "stand" (ā la SliMP3) or the new front panel for the HDR... But I couldn't wait, so I just use my little PanaVise to hold it up!

So I guess the next step will be figuring out what else to display, though I like that I don't have to change inputs and click a button to see what the other TiVo is doing...

Is there a way to change the update frequency? BTW, I haven't noticed the momentary hang when it updates...

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Francesco
Your services might be as useful as a barber's shop on the steps of the guillotine.

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