Let’s talk about pixel tape....

[alistermorton]

Those STM32 boards are ridiculously cheap given the punch they ought to have. I may have to get a couple, especially as it ought to make integrating pixel driving and DMX easier.

[musht]

Don`t know where the STM32 fits into the micro hierarchy, in a world where a basic 8 bit MCU can now be less than 10p :-0

If you have any direct links to libraries please add them, doc is editable

 

https://docs.google.com/spreadsheets/d/10pHG7_VIVltyqJK1Y0T5g3Iq6YJV2MnhMp3UcAVB-GA/edit#gid=1543805468

 

Few 8266 compatible projects there already.

 

ESP32 is likely to become popular,much more processing power than `66, onboard wifi, 18650 battery and OLED display for under a tenner.

 

Teensie appears to be popular choice for large pixel count projects.

 

Arjan`s bare metal programming on Allwinner H3 http://orangepi-DMX.org/

 

If looking at older libraries, just be aware of a subtle change in timing spec:

 

http://doityourselfchristmas.com/forums/showthread.php?51313-Has-WS2811-timing-changed

[timsabre]

The first one in your table, octows2811 was the one I was thinking of.

[bruce]

So I’ve now got a few bits and pieces - some tape and an arduino - and more bits on order. Having fun already!

 

Next question - what’s the best way to power all this stuff?

 

I’ve already got lots of 12V “conventional" tape and controllers. For that, I’ve got a few 65W Meanwell “laptop-style” 12V supplies, which are ideal - each can drive about 5M of 5050 tape.

Having these style of PSUs also makes things simpler for PAT-testing purposes!

 

 

Pixel tape appears mainly to be in 5V variants, although there is some 12V.

 

At present, I’m driving 5V tape via a bench supply. There are plenty of industrial-style “open chassis” high current 5V supplies around, but these aren’t suitable for events unless properly boxed up.

 

So, several options:

 

1. Use 12V tape, and the existing type of power supplies. One downside of this is that I then need to think about 12V-5V converters to drive the arduino boards.

 

2. 5V tape, with a big 5V supply, boxed up, with multiple outputs.

 

3. 5V tape, with multiple small “laptop-style” PSUs.

 

4. Something else.

 

 

 

Any thoughts? What’s common practice elsewhere?

[timsabre]

12v pixel tape runs 3 leds per pix which makes it not suitable in a lot of situations.

 

The pro systems I have seen and worked on include a big 5v psu (usually meanwell type module) inside the driver case. If you want more tape / more power you just add more drivers.

[gyro_gearloose]

If you want to drive 'conventional' non-pixel LED tape with your Arduino you will need some MOSFETs to switch the power to the LEDs, as the Arduino can't directly switch the several Amps of power that the LEDs will use. This page tells you all you need to know about the hardware and software.

 

You could try using one of these handy little interfaces between your Arduino and your 12V LED tape. On the input side they have three opto-isolators, and the output of these drive three MOSFETs which switch the power to the LEDs.

 

You shouldn't need a dedicated 12V-5V converter to power your Arduino as it should have one fitted already! All of the pre-made boards, and the boards I designed myself have an LM7805 linear regulator to step the incoming DC voltage down to the 5 volts that the Arduino needs.

[Gerry]

 

You could try using one of these handy little interfaces

Are these https://www.aliexpress.com/item/32899970205.html?spm=2114.search0302.3.15.5ba344bbQyOoyp&ws_ab_test=searchweb0_0,searchweb201602_0,searchweb201603_0,ppcSwitch_0&algo_pvid=dbe6d143-1763-4a54-ac82-42e8dd890d80&algo_expid=dbe6d143-1763-4a54-ac82-42e8dd890d80-2 the same?

Cheers

Gerry

[david.elsbury]

 

You could try using one of these handy little interfaces

Are these https://www.aliexpress.com/item/32899970205.html?spm=2114.search0302.3.15.5ba344bbQyOoyp&ws_ab_test=searchweb0_0,searchweb201602_0,searchweb201603_0,ppcSwitch_0&algo_pvid=dbe6d143-1763-4a54-ac82-42e8dd890d80&algo_expid=dbe6d143-1763-4a54-ac82-42e8dd890d80-2 the same?

Cheers

Gerry

yes looks like it (noting that it’s NOT suitable for pixel tape; but I think this is a tangent anyway? ) :) Edited January 5, 2020 by david.elsbury

[Tomo]

I often use 5V tape with an ATX PC power supply, mostly because I happen to have a few of them knocking about.

 

Note that they aren't always particularly stable with zero load on the 12V line, but that's easily sorted.

[bruce]

ATX PSU is not a bad call..... and I also have a large supply of them....

[musht]

12v pixel tape runs 3 leds per pix which makes it not suitable in a lot of situations.

 

Couple of variants 3 LEDs in series like a normal RGB tape with a driver IC also a variant with on board buck convertor on back of tape evry 300mm or so.

 

Most recent WS2815 is a 12V native pixel LED, internally the 3 LEDs are in series and are shorted out by fets, 12V supply still standard 5V WSXXXX data.

 

Big advantage on longer lengths, less power injection.

 

ATX PSUs for 5V and for massive 12V PSUs , HP Server supplies , popular with coin miners, get nice fused break out cards for them.

 

More compact to case Meanwell LRS series are very popular.

 

Amazon random no name PSUs can vary from OK to really scary.

 

Remember that data always needs a clean common ground.

[timsabre]

Ok interesting, I have only seen 3 leds per pix versions at 12v.

[musht]

They`re on the Tacklind list Tim ;-)

 

TBH we are all wanting RGBAWUV 36V 24bit 2020 pixels, but not there yet.

 

Driving strategies are getting clever:

 

`4 pins 6000leds at 90fps using the new driver you can drive 8 strips from one pin of the esp32`

 

[timsabre]

Do you know of any pixel tape with better than 8 bit dimming? I keep getting asked about this...

[musht]

UCS8903, UCS8904, MY9231, MY9291 list from about year ago, rare to see them in the wild in something useful like tape.

 

World Semi about to launch a new 16 bit in 2121 format aimed at screen makers.