Author Topic: PicCap 1st Pixel Length  (Read 915 times)

Offline PeteyHall

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PicCap 1st Pixel Length
« on: March 03, 2017, 07:08:11 AM »
With my f16v2's, I was able to get over 50' without issue to the first pixel over cat5e without needing a uamp (100 pixels per run), can I expect the same length expectation with the cap as well or is it less?

Thanks

Offline JonB256

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Re: PicCap 1st Pixel Length
« Reply #1 on: March 03, 2017, 07:19:09 AM »
It will be less, perhaps a lot less.

One of the Caps I have was an early design without "buffer" chips. The buffers take the 3.3v data signal and upgrade it to the 5.0v data used by pixels.
If you don't have buffer chips, distance is probably less than 12 inches. With buffer chips, you will go farther but maybe only 5 to 10 ft. You can extend that by using Cat5 or null pixels or uAmps.

I have not tried for long distances from a PiCap. I've gone 5 feet without problem. Perhaps others will chime in with their actual distance successes.

Offline PeteyHall

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Re: PicCap 1st Pixel Length
« Reply #2 on: March 03, 2017, 07:27:22 AM »
Thanks.  I'm going to be adding a few to remote parts of my house where I really don't want to have to run cable to and was hoping to get similar distances using the 'new' buffered outputs Dave is selling.

Offline Michael

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Re: PicCap 1st Pixel Length
« Reply #3 on: October 14, 2018, 08:41:20 PM »
How can I tell if my picap has buffer chips?  I have 24v WS2811 floods connected and the floods stop responding to any data after awhile.  I have to disconnect power to get them to respond again. My distance to the first flood is about 15 feet.

Offline Bwinter

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Re: PicCap 1st Pixel Length
« Reply #4 on: October 14, 2018, 08:53:03 PM »
Which PiCap is it/who did you get it from?  Have a pict?

Offline Michael

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Re: PicCap 1st Pixel Length
« Reply #5 on: October 14, 2018, 09:47:53 PM »

Offline Bwinter

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Re: PicCap 1st Pixel Length
« Reply #6 on: October 14, 2018, 10:03:39 PM »
Yes, that one is buffered.


Remember though, that only counts for getting to your FIRST pixel, and has nothing to do with getting from your FIRST to your SECOND pixel (that signal is generated from the first pixel).  If you need to go a long distance between pixels, you may need to use an Amp.

Offline JonB256

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Re: PicCap 1st Pixel Length
« Reply #7 on: October 15, 2018, 06:07:25 AM »
Yes, that one is buffered.


Remember though, that only counts for getting to your FIRST pixel, and has nothing to do with getting from your FIRST to your SECOND pixel (that signal is generated from the first pixel).  If you need to go a long distance between pixels, you may need to use an Amp.

I know it would add to the cost of a PiCap (currently $35), but it would be sweet to embed the equivalent of an F-Amp to the output of a PiCap. It could probably just replace the current buffering chip (whose major purpose is to bump the data voltage from 3.3v to 5.0v).

Offline Michael

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Re: PicCap 1st Pixel Length
« Reply #8 on: October 17, 2018, 09:53:44 PM »
I would love to add the uAmps, but my floods are running at 24V.  The issue I am seeing is the lights stop responding at different times.  Right now I have a very simple sequence running a single color pattern.  They just stop.  Restarting the FPPD fixes the issue.  I can't tell if data has stopped being sent from FPP or there was a glitch in the data causing the WS2811 (Robg) flood to stop responding due to the cable being too long.  I am gong to try a string of lights this weekend and see if there is a difference. 

Offline Bwinter

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Re: PicCap 1st Pixel Length
« Reply #9 on: October 17, 2018, 10:58:33 PM »
I would love to add the uAmps, but my floods are running at 24V.  The issue I am seeing is the lights stop responding at different times.  Right now I have a very simple sequence running a single color pattern.  They just stop.  Restarting the FPPD fixes the issue.  I can't tell if data has stopped being sent from FPP or there was a glitch in the data causing the WS2811 (Robg) flood to stop responding due to the cable being too long.  I am gong to try a string of lights this weekend and see if there is a difference.

Be careful about using the uAmp/fAmp, as they only support 5-12V, and if youre running 24V floods (like I am), the fix is more complicated.

This is why I wish I knew the schematic for these Amps, so I could have had a better solution....

Offline AAH

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Re: PicCap 1st Pixel Length
« Reply #10 on: October 17, 2018, 11:56:12 PM »
I would love to add the uAmps, but my floods are running at 24V.  The issue I am seeing is the lights stop responding at different times.  Right now I have a very simple sequence running a single color pattern.  They just stop.  Restarting the FPPD fixes the issue.  I can't tell if data has stopped being sent from FPP or there was a glitch in the data causing the WS2811 (Robg) flood to stop responding due to the cable being too long.  I am gong to try a string of lights this weekend and see if there is a difference.

Be careful about using the uAmp/fAmp, as they only support 5-12V, and if youre running 24V floods (like I am), the fix is more complicated.

This is why I wish I knew the schematic for these Amps, so I could have had a better solution....
All of my Null Pixel Buffers ( http://www.hansonelectronics.com.au/product/null/ ) have been 5-24V since I did the 1st batch. All new stock that goes out now and all of the ready to go nulls (null with pigtails fitted) are 24V compatible.

On a side note the rPi-28D that I make which is similar to the PiCap and others has buffered pixel outputs and in theory should give a similar 20-30m range to the 1st pixel like the Null does. There's a video of the Null in use at the bottom of the linked page above. The difference between pixel output and the buffered output was 5m to 30m from memory.

Offline Bwinter

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Re: PicCap 1st Pixel Length
« Reply #11 on: October 18, 2018, 12:04:46 AM »
Good to know these are out thereI hadnt seen your site.  Over the last two years, Ive bought Amps from two different vendors and neither of them now exist.

These would have saved me some hassle when I was trying to get my 24V floods going....

Offline pixelpuppy

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Re: PicCap 1st Pixel Length
« Reply #12 on: October 18, 2018, 07:26:43 AM »

With my f16v2's, I was able to get over 50' without issue to the first pixel over cat5e without needing a uamp (100 pixels per run), can I expect the same length expectation with the cap as well or is it less?
The Falcon PiCap. https://www.pixelcontroller.com/store/index.php?id_product=47&controller=product


The Falcon V2 controllers and the Falcon PiCap both use Texas Instruments SN74AHCTxxx buffer chips.  They are essentially the same with the difference being the bigger controllers use more buffer gates for more ports.  I would expect their driving distances to first pixel to be essentially the same.
xLights and Vixen3 for sequencing / FPP for scheduling and playing / Falcon controllers for pixels / homemade controllers for everything else

Offline Bwinter

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Re: PicCap 1st Pixel Length
« Reply #13 on: October 18, 2018, 09:53:42 AM »
So I think the bigger question here  is comparing the output from the Falcon/PiCap (SN74AHCT) versus a u-Amp or f-Amp.  I presume they use different mechanisms (other than the quad versus single gates)? How do they differ?

Offline JonB256

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Re: PicCap 1st Pixel Length
« Reply #14 on: October 18, 2018, 10:35:05 AM »
So I think the bigger question here  is comparing the output from the Falcon/PiCap (SN74AHCT) versus a u-Amp or f-Amp.  I presume they use different mechanisms (other than the quad versus single gates)? How do they differ?

Either Corey or DPitts could give the "exact" answer but primarily, (my recollection from u-Amp Coop discussions) the u-Amp and F-Amp use a MOSFET amp with a higher slew rate than the output stage of the SN74AHCT. That gives sharper corners to the DC Waveform and allows it to travel longer distances before losses in the wire degrade the signal to "just noise."

 

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