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Topic: Design Challenge: 64x64 led matrix as cheap as possible (Read 7670 times) previous topic - next topic

PaulRB

Aug 16, 2014, 11:15 am Last Edit: Aug 16, 2014, 04:15 pm by PaulRB Reason: 1
Hi everyone,

Would like to hear thoughts & suggestions for the cheapest way to construct an led matrix:

- only single colour needed
- individually addressable but no fading/pwm needed
- indoor use, don't need high brightness levels
- pattern update speed 10-20 frames per second
- pre-built modules or individual leds (I realise 4000 leds is a lot of soldering)
- multiplexing by Arduino or other chips
- commonly available (worldwide) components from eBay for example
- constructable at home with typical basic diy/electronics skills & tools
- only cost of components & shipping counts.
- Labour/time soldering, constructing and programming are free, as this would be a hobby rather than commercial venture.


Here is my best option so far:

http://www.ebay.co.uk/itm/LED-Display-panel-dot-matrix-64x32-/221411387445?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item338d25a835

2 of above totalling £108. Simplest contruction, too! Don't need bi-colour though.

Thanks Paul

bobcousins

#1
Aug 16, 2014, 02:59 pm Last Edit: Aug 16, 2014, 03:08 pm by bobcousins Reason: 1
At 2.6 pence per pixel including controller, that is not bad value.

Individual LEDs can be had for about 1p each in 1000 pcs. You then need a PCB and controller.

The embeddedadventures panel is composed of 8x8 LED panels. For 50pcs of 8x8 you can pay around 75p each, which is also around 1.1p per LED, so you may as well buy 8x8 panels.

That would leave about £1 for controller chips and PCB for each 8x8 panel. Even if you price construction time as 0.00/hr, it would be hard to beat 2.6p/pixel, I think.

Then there is also debugging time and writing code to add, which ea provide already.

Unless you can get some really great bulk prices, or can think of a clever way to control 64 LEDs for 50p, I think the ea panel is looking like the best option.

ETA: found something that might work out cheaper http://www.dx.com/p/diytj-16-x-32-dual-color-dot-matrix-module-kit-green-white-202393#.U-9WxmOIpdL

Some assembly required, but comes to about £80 for 64x64 display.
Please ask questions in the forum so everyone can benefit. PM me for paid work.

PaulRB

Thanks bobcousins, a good find.

I will add another criteria: only cost of components & shipping counts. Labour/time soldering, constructing and programming are free, as this would be a hobby rather than commercial venture.

bobcousins

Well this has piqued my interest, I am currently building and LED clock. I just discovered addressable RGB LEDs! Nice but pricey for large arrays.

Another question would be overall size?

The embeddedadventures panel you linked uses 32x32mm modules.

There are 8x8 modules in a 19mm size, 35p per module http://www.ebay.co.uk/itm/UN3F-10PCS-LED-Dot-Matrix-Display-Module-Red-16Pin-8x8-Common-Anode-/291171607764?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item43cb2e24d4

If you put 8 of those onto a 38x76mm PCB, you would need 8 PCBs to make a 64x64.  ITeadStudio will do 10pcs for $15, plus a bit for shipping. Then add 2x138, 4x595.

If I got my sums right, that's about ~£40. Overall size about 15x15cm.

I looked at using SMD Leds, 1000 off 0603 for £7.50, but that works out more expensive than an 8x8 module, and 4096 0603's would be a challenge. Maybe doable with a toaster oven :)
Please ask questions in the forum so everyone can benefit. PM me for paid work.

bobcousins

I think the Chinese have beat me to it again : 64x32 red-green with drivers for $26 http://www.led-card.com/product_info.php?cPath=27&products_id=112
That's about £46 for 64x64 including shipping, £6 for assembly is hard to beat :)

A colleague tells me Chinese cities are festooned with LED displays, I can see why. That also maybe explains China's huge demand for power generation!
Please ask questions in the forum so everyone can benefit. PM me for paid work.

PaulRB


I am currently building and LED clock. I just discovered addressable RGB LEDs!


There's a coincidence! I'm working on exactly that myself:

http://youtu.be/47fWT0pi07U

PaulRB

#6
Aug 16, 2014, 07:38 pm Last Edit: Aug 16, 2014, 08:11 pm by PaulRB Reason: 1

I think the Chinese have beat me to it again : 64x32 red-green with drivers for $26 http://www.led-card.com/product_info.php?cPath=27&products_id=112


Typical Chinese description, though:

Quote
P4.75 Indoor SMD single color LED module


OK...

Quote
Brightness adjustment: 256 Levels of each color(R,G,B)can be adjusted manually and 8 levels of each color can be adjusted antomatically


Hmm... no, I don't think so

Quote
Input signal: RF,S-Video,RGB,RGBHV,YUV,YC,COMPOSITION etc.


Definitely not...

Quote
Control ststem: PCTV mon-linear editting card+DVI display card+main controller card+optic fibre transmiddion


They have no idea what they are saying in "English"...

Not that I speak a word of Mandarin, but I'm not selling them anything.

Quote
A single order's delivery fee will be 25 USD or 20 Euro, no matter how many goods added in the order.


Ah... that bumps the price up somewhat.

Still, another excellent find!

bobcousins

We can also throw MAX7219 (36p each, 10pcs ebay) and TLC5940 (53p each, 10 pcs ebay) in to the mix... at which point my brain becomes full and there are almost too many possibilities to consider.

So... I am wondering what the solution to the challenge was ?
Please ask questions in the forum so everyone can benefit. PM me for paid work.

PaulRB

I have an approx price in mind, but the cheapest solutions so far are still a ways above it. I could afford it but its an interesting challenge to think how low a hobby design could go.

Paul

Silvius

 :)  Interesting challenge indeed...

I noticed that smaller modules (32x16) are more cost-effective than their larger counterparts (32x32, 64x16,...).

For instance, I found this module (32x16, green)
£12.23 / lot (2 pieces free shipping) ~£6.12 / piece

So, for 64x64 matrix we need 8 modules £12.23 x 4 = £48.92
So far this is the best price that I could find for this challenge...

P.S.
I posted an article here about a similar module (32x16, red,green)

PaulRB

Hi Silvius, you woke a year-old thread!

I still have not build a 64x64 matrix, but it is still on my to-do list. The best i have found recently is this which would cost £33.12.

Paul

Silvius

 :-[ ... "mea culpa" ...

I was tricked by the dates "Aug 25, 2014" vs "Aug 25, 2015" :)
...also this thread was among the first 5 threads o this section.

Anyway. It works for me...
Thanks to you I found a cheaper alternative for these modules.

Best regards!

vffgaston

#12
Aug 26, 2015, 10:43 am Last Edit: Aug 26, 2015, 10:44 am by vffgaston
I've tried this; it works fine

http://www.ebay.co.uk/itm/Display-de-16-x-64-LED-s-gran-formato-304x76-mm-Electronic-LED-banner-arduino-/231595328041?hash=item35ec284229

Regards

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