View Full Version : USB Grinch Interface

01-23-2008, 03:34 AM

have you seen this link?

has anyone tried it? etc etc.


Looks like it could be a good base to build on. standard hardware thats easy enough to get.

what do people think?


Peter Rogers

01-23-2008, 07:21 PM
I like it... does it work?

01-24-2008, 01:59 AM
i only know whats on the webpage.

im hoping to build one on a breadboard at least over the weekend

ill see how i go


01-24-2008, 09:43 PM
Does anyone know if he is registered here... Maybe pteller


01-24-2008, 10:51 PM
Last I knew he gave up on it. I can't remember why I think he was havinf errors in communications or something. I know I looked at one time.


01-25-2008, 01:37 AM
I think at this point, there is already the RenC and the DMX-Grinch - so - its kinda of a non-issue, as both can use a USB-Serial interface to operate with.

01-25-2008, 03:42 AM
the reason i was interested in it was as a usb-ledtricks addition not so much a grinch interface.

plus its something else to play with.

so if theres any more info around please feel free to pst me


01-25-2008, 11:18 PM
I think at this point, there is already the RenC and the DMX-Grinch - so - its kinda of a non-issue, as both can use a USB-Serial interface to operate with.

Actually I think the Idea would be to build it onto a updated grinch board. No separate intermediate board. :)

01-25-2008, 11:39 PM
I never did run down the source of the intermittent communications errors at higher channel counts and baud rates. I didn't have a full '595 setup, so it was hard to test. The commercial USB adapters worked for most people, and with the Ren-C out now there just isn't much need.

I think either a '2550 or a '4550 would make a great front end to a Ledtriks, but with so many people working on similar designs, I've been working on other projects instead.

Just about everything I have is on the website, but I'm happy to collaborate if someone wants to push the dessign in another direction.


01-26-2008, 02:39 AM
well, as i have said i hope to give it a shot soon,

the thing i couldnt work out is why you used the renard plugin. it adds alot of extra code i would have thought.

i guess the idea of not having to make a new plugin was to great.

anyway the idea of adding it to a ledtricks is where i would like to take it. but i dont have a ledtricks yet so im testing with the grinch.


01-26-2008, 11:36 AM
You are exactly right about the plug-in. At the time I was working on the hardware there were still very few people writing plug-ins and they were working hard on projects that had a lot more general interest.

This may be better suited for the ledtricks forum, but what strategy are you thinking of? I was leaning towards defining a font in firmware and sending text and scrolling direction and rate from Vixen. Add 60 custom frames for animation and you would have a lot of capability without much load on the CPU...


01-26-2008, 04:27 PM
right now i was thinking KISS principle. Keep it simple stu..d.

simply have it recieve 16 x 48 bits of binary info for on off info.

maybe in a packet format like row#,colum Data... , Stop.

adding fonts and different features could be added later quite easily i think once the interface is stable . but i hadnt really thought to much about that.


01-26-2008, 04:42 PM
Simple is good. I don't have a lot of insight into where the performance load is with the current design, and I'm looking forward to knowing if it's in generating the frames or just clocking them out to the board...

Please let us know what you find out!


01-27-2008, 08:23 PM
well i have it fired up on a bread board. doing a simple test seems to work ok.

ill give it a harder test once i have some more time.

one thing i found out that i didnt know is that vixen only sends packets when the lights update.

ie i have it set to a 25ms sequence but if i only change the lights every 500ms it only transmits every 500ms. not what i expected.

time to start playing.

01-27-2008, 08:45 PM
Yeah I remember the discussions regarding the DMX packets and there was mention there that Vixen only sends out data when items change, unlike DMX which constantly repeats the data over and over. You can easily detect when a DMX fault occurs as there is suddenly no DMX data (and I believe that the DMX version of the Renard firmware then fades to 0 over time), but if Vixen fails you never know about it as the lights just freeze where they are.

02-29-2008, 06:35 PM
Will someone look at this and give me their opinion? Looked like a winner to me.