Muff's Modules & More

DGTom · Posted: Sun Feb 06, 2011 12:04 am Post subject:

I think I've finally found the perfect partner for my Benjolin.... CVing & clocking one another love

sealion · Posted: Sun Feb 06, 2011 12:42 pm Post subject: bitvision kit

Hmm, same flashing left led issue, regardless of source, reheated for cold solder joints, nope that's not it.

sealion · Posted: Sun Feb 06, 2011 12:44 pm Post subject:

giorgio
still have that bitvision led issue? me too, a puzzlement, not cold solder issue. parts issue, something reversed? ?

lizlarsen · Posted: Sun Feb 06, 2011 6:49 pm Post subject:

Does the flashing rate of the left LED seem to be connected to the flash rate of the right LED at all? I'm wondering if some sort of crosstalk might be happening.

sealion · Posted: Sun Feb 06, 2011 8:50 pm Post subject:

No its a fairly steady rapid flash that does not vary with the gain pot. Sort of one-one-one-one. Gain makes no changes to it, nor do any of the buttons. It blinks when there is no audio input hooked up or if there is, its at the same reate, quite constant.

The led on the right is quite slow and only slows a bit with parameter 1, no change with parameter 2. Its rate is sort fo waltz time, one and two, one and two.

Possibly related the trim pot to counter-clockwise never seems to get to black & white after dozens of turns.

lizlarsen · Posted: Mon Feb 07, 2011 12:16 am Post subject:

Hi sealion -- solder job looks nice and clean, good job! Yeah that doesn't sound right about the LEDs. Double check the orientation if you can. As for the trimmer, do you see the color scaling changing as you adjust it? It is a 6-turn trimmer. You're basically scaling the DAC voltage going to the phase shifter. If you could, do you have a way to take some snapshots of the output or capture a clip, going thru different images?

I've personally handbuilt over 20 of these with this same board revision/BOM, so I'm sure we'll get it sorted. smile

lizlarsen · Posted: Wed Feb 09, 2011 3:16 pm Post subject:

Here's a quick preview of the Bitvision image & palette editor tool I've been working on. It's going to be pretty bare bones at first, but we'll keep improving it. In addition to defining a custom image and palette for each "program", I'd also like to be able to reconfigure the actions of the param knobs and mode/action buttons on a per-program basis (so kind of like a modular control patch that you set up in this editor, and gets encoded with the image+palette.) So you could have 16 different image/palette/control patch combinations loaded on the BitVision at once.

stin-g · Posted: Wed Feb 09, 2011 3:55 pm Post subject:

That's one of the coolest dang things I ever did see. applause

Can't wait to try it out! You rule Lars!

giorgio · Posted: Wed Feb 09, 2011 4:11 pm Post subject:

lizlarsen · Posted: Wed Feb 09, 2011 4:19 pm Post subject:

Hey Giorgio, it looks like some bad AVR chips may have gone out with these kits! I've been looking into this with sealion and believe that I didn't pack the AVRs well enough, and it's potentially been damaged during shipment (I apologize for that.) I had a BitVision here that I just did rework on (leftover one that didn't test OK from the last building run) and it had the exact same issue that you're both describing. New AVR fixed it right away.

You guys are both definitely not seeing the correct behavior out of your BitVisions yet. Shoot me an e-mail and we'll get it sorted out, either you can send it to me and I'll install a new chip and confirm it's all good -- or I can send you a new chip.

giorgio · Posted: Wed Feb 09, 2011 4:22 pm Post subject:

IIRC the AVR chip was just floating in the bag of parts, which I kinda found odd, but in any case, I am not worried about it at all thanks to your support!

i'll drop you an e-mail now

thumbs up

lizlarsen · Posted: Wed Feb 09, 2011 6:04 pm Post subject:

I've just uploaded the source code, the editor utility, and some very brief step-by-step instructions for adding your own images and color palettes on the BitVision webpage here:
http://www.lzxindustries.net/bitvision

Keep in mind this is a big work in progress! BitVision is meant to be a development board for "vintage audiovisualizer" type applications, and there is much more to be explored. Let me know if you've got questions and looking forward to feedback.

andrewF · Posted: Wed Feb 09, 2011 6:56 pm Post subject:

Thanks Lars
got my programmer yesterday
think I will start making up some 32x32 bit images and get some hex files ready.

This is such a fantastic project! love

lizlarsen · Posted: Wed Feb 09, 2011 9:48 pm Post subject:

I'm also happy to report that I have BitVision working in PAL now too. This requires population of an alternative crystal (17.73MHz) and different code. Given the really grungy response of the color phaser, I was wondering how this would look and it's surprisingly very interesting.

The downside is that I'm not getting the full range of color shift that the NTSC version has, something that may be able to be improved -- I'll look into it, but it seems like the NTSC version is more tolerant to the upper extremes of the chroma shifter. PAL is only getting green and blue parts of the spectrum, with hints of orange and purple coming through at times.

If you are DIY'ing the circuit, one solution (and this goes for the NTSC version to) is to lengthen the stages in the phase shifter delay line. Currently it is 4 stages, lengthening to 8, 12, etc. will allow a smoother response.

On the other hand, PAL speeds are allowing me to show a few more pixels and increase the image (but not buffer) size a bit.

lizlarsen · Posted: Wed Feb 09, 2011 11:53 pm Post subject:

I've uploaded a version of the source code for PAL here:
http://www.lzxindustries.net/bitvision_pal_1.0.zip
The only hardware change required is changing the crystal to a 17.73MHz part, such as this one.

Due to the fact that I may not be able to get the full color palette range for PAL with the current hardware design, I'm going to wait and get some field reports of anyone willing to test it out and see if it can be improved first, before I start offering an official PAL version. There is always the option to use an NTSC to PAL converter, like this one (maybe cheaper options out there) -- always something useful to have around anyway! But I'm betting we can get this running full speed with a little tweaking.

If you're one of the several who want this running in PAL, send me an e-mail if you'd be willing to give it a shot and I can put a bare-bones kit together for you with both crystals, just realize it's not fully there as far as color response goes just yet.

lizlarsen · Posted: Thu Feb 10, 2011 2:40 pm Post subject:

Pulled it back out to try to clean up the PAL code a bit today and got it working much better, so I think it's good to go -- just need to populate a 17.73MHz crystal instead of the one included in the kit. So those of you that want a PAL kit can go ahead and order one from Switched On. If you need the 17.73MHz crystal, I bought several, so just e-mail me with your address and Switched On receipt and I will stick one in the mail to you. Next time I do a production run of these (it may be a while), I'll include PAL & NTSC crystals in all the kits.

The PAL color subcarrier is a lot touchier than NTSC as far as valid ranges go, so it can't get as grungy and bleeding as the NTSC version, but we're seeing the full color palette now, which was the important part. I encourage anyone with the PAL circuit to play with resistor values in the HC4053/HC14 areas of the circuit -- there's a lot there to be modified and played with that will alter the color response.

I've uploaded the improved PAL code over the original zip file linked in the last post.

blue_lu · Posted: Tue Feb 15, 2011 5:36 am Post subject:

+1 on the PAL Version!

also emailed you! this looks fantastic!

applause

BugBrand · Posted: Mon Feb 21, 2011 4:57 am Post subject:

Lars, this look pretty damn cool.

I'll email you to discuss some bits including a PAL one of these.

Nice!

lizlarsen · Posted: Wed Feb 23, 2011 11:58 pm Post subject:

Hi everyone! I'm very pleased to announce that I've solved the bug issue that a few of you were experiencing with your BitVision kits with a firmware update (available for download on the website here: http://www.lzxindustries.net/bitvision)

I've e-mailed the few of you I promised new AVRs too, but just mentioning it here in case anyone else pops up with the same problem!

andrewF · Posted: Tue Mar 22, 2011 7:05 pm Post subject:

Got my BitVision up and running last night with CV inputs for the parameter pots, gate inputs for the momentary switches, DC bypass and separate clock input.

The CV input cct I posted previously has been slightly changed to get a better range out of the input CV
This and the gate cct are both on my site, if they get updated the date of the latest version will be on the link.
The gate cct is VERY simple, I didn't even need a PCB, just twisted the leads together and soldered them to the jacks.

See vidsynth page for pics and PDFs

Switches out of some 50s lab gear
THANKS Lars for the kit and sharing this great design.