View Full Version : How many pixels can the FPP control with a pi hat

04-06-2017, 08:10 PM
I just got 2 Falcon pi hats and am wondering how many pixels I can control with each. Christmas in July is almost here!

04-06-2017, 08:57 PM
i have had 700 on mine (350 per output). i am told 800 is the limit.

04-06-2017, 09:05 PM
I been looking at the for possible applications.....Web Spec's says "This boards supports two pixel outputs of 512 RGB pixels"

Edit: Martin, the above is Ron Holiday's Pi Pixel Adapter

The Falcon PiCap refers to 800+, but not clear if that is 2 X 800+ or 800+ total. I think it's 800+ per output or 2 X 800"
...."Can control two strings 800+ "

Pi Hat Pixel board by Andy Harrison is undefined

04-08-2017, 12:59 AM
Somewhere on this board I saw a post that said if you edited a file, you could get 1000. I need to find that post. I just calculated I need just over 800. Will post the link if I find it again.

04-08-2017, 01:18 AM
Somewhere on this board I saw a post that said if you edited a file, you could get 1000. I need to find that post. I just calculated I need just over 800. Will post the link if I find it again.

FPP will allow inputs up to 1000 Pixel per output....that 6000 channels.
I guess if you are looking at maybe 800-900 pixels, any of the 3 listed boards I listed would work for you

04-08-2017, 01:24 AM
Then I am good, was at 810 total or something. Thanks.

04-08-2017, 10:17 AM
I controlled a 800 pixel mega tree last year with no issues on 1 output.

04-08-2017, 10:36 AM
If the previous poster was correct and it can do 512 per port, then you should be all set. 2x512 = 1024

04-08-2017, 12:44 PM

04-10-2017, 07:27 PM
I tested several models of PI's and there's a soft limit around 1400 pixels total on the Pi 3. (700 per port)

Dirty little secret:

The next release of FPP will support three outputs, once the pi hats have been updated. Doesn't change the global soft limit though, but give you three strings. I tested 500 x 3 strings for 1500 pixels total and it seems to run fine.

04-10-2017, 10:35 PM
Dang it now. I was all set to order my second set of PiHats. :(
Now I'll have to wait for the newer version. (Actually, I could really use the 3 outputs.)

Any idea as to approximately when?

04-10-2017, 10:39 PM
No, because it's up to Dave to redesign the Falcon pihat. I wrote the driver for the third output and submitted it to FPP devs.

I don't expect it anytime soon but if you can hold off he might pull it out before the Season gets too close.

04-10-2017, 11:06 PM
Define, "too close". :omg:

Right now patience and waiting are not my strong suite. I'll try to improve.

04-11-2017, 06:50 PM
curious....on the third output. What pin are you using? Jer wrote the original code and it used the two hardware PWM channels, so how are you doing the third? I could spin my board pretty quick if there is interest.

04-30-2017, 09:41 PM
There is interest :hmm:

05-02-2017, 10:35 AM
I've yet to hear back what pin the OP is using for the third channel. The Pi only has two PWM channels, and these are being used to generate the data. I have my reservations if a third channel is actually feasible.

05-02-2017, 10:41 AM
My pluggin is checked into the FPP github and there's a several pages of development on the Falcon forum. You are welcome to test it yourself.

Sent from my Nexus 5X using Tapatalk

05-02-2017, 03:38 PM
I've asked what pin the 3rd output is on, and nobody seems to know. The Pi uses the two hardware PWM channels, based on the code Jer wrote, so I'm still waiting to find out where the 3rd is coming from? I'll be glad to update my PixelPi board to support 3 channels once I know it actually works.

05-02-2017, 06:22 PM
It appears to be the first spi interface? I can't seen to track down the code right now. The posts appear to in the running on other hardware thread? Have to know the mode apparently as different pins are used depending on mode. My guess is pin 12 - but I think MadSci1016 could clear that up pretty quick.

05-02-2017, 06:59 PM
Yep. It works by using the SPI port to emulate WS281x signals. I've tested 3 strings of 500 pixels each with no issue.

My driver code is sitting in a pull request for the main development branch of FPP. Means unless I (or someone else) take the time to back port it to the 1.5 branch it won't be included until 2.0 is released.

You can test it by compiling FPP from my fork on Github. I go by the same username there as here.

Sent from my Nexus 5X using Tapatalk

05-03-2017, 12:07 PM
Interesting...using the SPI port. I'm surprised that it can generate the timing in the hardware for this, Jer was thinking it wouldn't work but...hey if it does thats great.

I'll see if I can get some time this week to build FPP from the repository and modify a PixelPi board to drive the pixel string.

05-03-2017, 08:30 PM
I can see it now. :munch::wacko::yeah: There will be PI's everywhere in my yard!!!!
Now if I could just figure out Wireless power for the whole yard :hmm:

maybe if I wound up some wire on a PVC pipe :freak: and suspended it next to a 13KV transmission line

:omg: on second thought I'll see if there is a sale on extension cords.

05-04-2017, 11:09 AM
wireless power = batteries? :-)

05-04-2017, 02:31 PM
Wireless like set the microwave on high and open the door and use all those old dish network "antenna" to translate the microwaves back into nice steady 12v. ;-)

05-09-2017, 07:07 PM
In error - sorry