Procyon Brightness Stepping
This is a known issue from back in 2007:
http://mindplacesupport.com/forum/sh...de)-in-Procyon
The easiest way to reproduce this is to set the segment time to 2:08 (128 seconds) and then pick only one color, set start/end amplitude to 0, and then ramp DC offset from 127 (0 brightness) up to 255 (full brightness) over the course of 128 seconds.
Especially near the beginning, you can see it "stepping" up in brightness roughly once every second. The first step is the most jarring, and the LED goes from 0 to "clearly visible" in a very big jump.
My understanding is that brightness is handled internally as an 8-bit value, and that it's mapped linearly over 255 levels of brightness.
However, my experiments make it seem like there are only 128 brightness levels. If I ramp from DC offset 127 up to 137 over 10 seconds, I can count 10 steps. Thus, there are only 128 brighness levels between DC offset 127 (off) and 255 (full brightness).
If I set frequency to 75 Hz (invisible flicker), fix DC offset to 127, and then ramp Amp from 0 to 10, I count only 5 steps. If I ramp Amp from 0 to 20, I count 10 steps. Thus, there are two increments in amplitude value for every true jump in brightness.
My guess is that there's something going on with the DC offset implementation that is wasting half of the 8-bit brightness space (DC offset 127 is actually 0, and DC offset 0 is being used to represent -127).
Suggested fixes back in 2007 were switching to 12-bit brightness levels or using a non-linear brightness mapping.
Even if you stick to just 127 brightness levels, it does seem like a non-linear mapping would be better here, as many of the brightness levels are "wasted" in the upper end. Jumping from a DC offset of 252 up to 255 is invisible, for example. Even 250 to 255 is almost completely invisible. So we have 5 levels there (or 2 of 128 steps) that are wasted, and could be used to reduce stepping in the low end. The first upper end step that I can actually see is 249 to 255. If I set up two segments that make that jump instantly, I can just barely see it.
Note that it's not just DC offset ramps that have this problem, but also the sine and triangle wave tables. Slow sine/triangle waves can be seen to step on the dim end, and suddenly go out in one big step at the very dimmest end.
I do wonder if there's some limitation of the PWM dimming that would prevent you from using even thinner pulses on the low end. There is a minimum increment size for PWM pulse width based on the processor's clock rate.
Is there any possibility of this getting fixed in a Procyon OS update?
I know it's an old, outdated product, but I just bought one direct from MindPlace. It suits my needs better than the Kasina.
Also, this might sound kinda crazy, but have you thought about releasing the OS source code so that the community can take over maintaining it?
Is there a huge danger of end-users bricking their own devices?
Re: Procyon Brightness Stepping
Hi Jason;
Love your enthusiasm!
Unfortunately, the Procyon (and Proteus and ThoughtStream)'s source code was produced by a gentleman who has not been with MindPlace for over 10 years. The Proteus and ThoughtStream are already discontinued, and the Procyon will be discontinued when the Limina comes out later this year.
I'm afraid it is what it is at this point. There won't be any OS updates for any of these discontinued products as we move to the new Kasina platform and format.
Re: Procyon Brightness Stepping
What's the Limina? Any info about it?
And if it will be discontinued, what's the harm in releasing the source code? I'm assuming you guys still have the source code, right? Even if someone else wrote it?
But I guess you're telling me that I just bought a losing horse! :)
Things I didn't like about the Kasina that steered me toward the Procyon:
1. Built-in battery. It will go dead someday before the device dies. I've got devices around the house that are still working 40 years later. No built-in battery lasts 40 years.
2. More advanced programming is only possible through SpectraStrobe audio format, which is a pain to author (the companies that used to make tools to author it have vanished, right?) and not that precise (no true square waves possible, etc.).
I'm on day 1 of owning the Procyon, and I'm already able to do all kinds of crazy things with the editor that would be impossible to do with the Kasina editor, and would take me weeks to figure out and perfect with SpectraStrobe format.
Re: Procyon Brightness Stepping
Quote:
Originally Posted by
jasonrohrer
What's the Limina? Any info about it?
Not much yet. It's a lower priced product to replace the Proteus and Procyon.
Quote:
And if it will be discontinued, what's the harm in releasing the source code? I'm assuming you guys still have the source code, right? Even if someone else wrote it?
Nope.
Quote:
But I guess you're telling me that I just bought a losing horse! :)
Not at all! The Procyon works very well for what it does. It was made about 15 years ago, and has sold tens of thousands of units!
Quote:
Things I didn't like about the Kasina that steered me toward the Procyon:
Allow me to be devil's advocate...
Quote:
1. Built-in battery. It will go dead someday before the device dies. I've got devices around the house that are still working 40 years later. No built-in battery lasts 40 years.
Most people DON'T want to have to change batteries. Almost all electronics uses rechargable Li-Ion/Li-Poly batteries these days. The nice thing about the Kasina's, though, is that it can be replaced, unlike Apple products!
Quote:
2. More advanced programming is only possible through SpectraStrobe audio format, which is a pain to author (the companies that used to make tools to author it have vanished, right?) and not that precise (no true square waves possible, etc.).
Not at all. The KBSv2 format allows complex sessions as well as square waves (and others). There are free plugins now for the SS format that you can use quite easily with your favourite DAW. Previous SS authoring software cost hundreds of dollars. Now you can do it for free!
Quote:
I'm on day 1 of owning the Procyon, and I'm already able to do all kinds of crazy things with the editor that would be impossible to do with the Kasina editor, and would take me weeks to figure out and perfect with SpectraStrobe format.
That's great! There's nothing wrong with the Procyon, and even if down the road you pick up a Kasina or Limina, I'm sure you'll still enjoy your Procyon. It's a great machine!
Re: Procyon Brightness Stepping
How does one go about purchasing and installing a replacement battery for the Kasina?
From what I've read, the battery is soldered in an not replaceable by end users.
Also from what I've read, the device will not function on external power if the internal battery is dead and cannot hold charge. See this:
http://mindplacesupport.com/forum/sh...+file+format#6
Re: Procyon Brightness Stepping
Quote:
Originally Posted by
jasonrohrer
How does one go about purchasing and installing a replacement battery for the Kasina?
From what I've read, the battery is soldered in and not replaceable by end users.
You may have misunderstood what I said. It most certainly can be replaced. By Mindplace or a service center. It's just not "user-replaceable". It is however a simple process for an electronic service person.
With proper battery hygiene, they should last many many years before needing replacing. Biggest thing is to always keep them charged as much as possible. Avoid draining completely and recharging. Use it plugged into a power source whenever possible. Batteries treated this way will last a VERY long time.
Of course, the Kasina console is covered by a 2 year warranty, so if for some reason the battery is not holding a charge as long as it should during that time, we will replace the battery at no charge.
You should replace the battery before that happens. You'll have PLENTY of notice - you'll start to notice that the battery is going dead more quickly than usual.
Re: Procyon Brightness Stepping
Well, it might just be an odd personal preference of mine, but sending a $300 device in for servicing (or opening it up myself and taking out a soldering iron) after 5-7 years of service is just not something that sounds appealing to me. I have enough friends with dead iPhones to know that it will be a very likely eventuality for the Kasina. Will this company still be around in 7 years? I hope so!
But if the Procyon had hard-wired batteries, I'd be stuck, unable to get it serviced, after you retired it next year. What happens when you retire the Kasina?
If one takes good care of ones electronics, they can last decades or even a century. Built-in rechargeable batteries just aren't compatible with that kind of potential longevity.
As a poignant example, I built my own simple mind machine when I was in college using a microcontroller. That was in 2001. It is now 2019, 18 years later. It still works fine. It does not have a built-in rechargeable battery, though. I imagine that it (and my new Procyon) will keep working for the rest of my life.
I would be overjoyed if you considered this point of view in your future product development. A rechargeable battery is fine with me on three conditions:
1. It is removable by the consumer without special tools.
2. It is easily purchased as a replacement from the OEM. That way, the consumer can stock up on back-up batteries for the future. OR it is a standard battery that is widely available.
3. The device runs happily on external power with or without the removable battery installed (so that in the inevitable future when the battery is no longer available, the device is still usable).
Here's an example of a device that did this 100% right:
https://shop.runcam.com/runcam-3s/
Notice the little battery door on the side. When I bought one of these, I also purchased two extra batteries for the future. And it runs fine on external power. It's already out of production, but I'm not worried. In fact, I bought it KNOWING it was retired, because these features made it future-proof.
For a device that's a little larger, you could probably avoid costly R+D by just using a single 18650, which would have the proper voltage and be easily acquired by consumers for the foreseeable future, even if the OEM no longer exists.
Re: Procyon Brightness Stepping
Also, maybe I'm missing something, but I've studied the KBS v2 editor, and it doesn't look like there are independent color frequencies and ramps. Looks like the color flash frequencies are determined by the sound beat frequency. There's no way to specify the frequency for R separate from G, like I can in the Procyon editor.
Re: Procyon Brightness Stepping
Quote:
Originally Posted by
jasonrohrer
Also, maybe I'm missing something, but I've studied the KBS v2 editor, and it doesn't look like there are independent color frequencies and ramps. Looks like the color flash frequencies are determined by the sound beat frequency. There's no way to specify the frequency for R separate from G, like I can in the Procyon editor.
That is correct. If you need colors to flash at different frequencies, then you would need to move to SS on the Kasina.
