If I'm reading that right, this isn't a business for you (you aren't making any money) -- you're just this super helpful guy, yeah?
And is the unit cost (per board) $45? Or is it 45 boards for $50, so about $1 apiece?
What sort of turnaround time would be involved for getting bare boards to Denver? And if you were to assemble these, what sort of cost and turnaround time would we be looking at? (I'm shooting for a April 30th completion for the entire project.)
And if it wasn't conveyed above, I'm very excited about this and appreciate the responses.
No, I do this a side business, for material is just basically covering costs tho, but it leads to custom design work, and assembly work, and we wrote a book that is published/distributed by a textbook publishing house, Cengage Learning, which we've received nice feedback on from forum members.
Paperback, kindle (e-book), and corporate distributions for companies that subscribe to Cengage (not sure how that works really, but I know Oracle personnel can get it electronically for example).
I ordered boards over the weekend, just waiting on arrival now. $45 + shipping for a 50-lot.
Went slow & cheap, so will have in about 3 weeks.
Cost to assemble/deliver: depends on how many, and what you want for headers, or no headers if you just want to wire from board to board. I can order those and the MAX7219s and sockets and resistors and capacitors, parts will arrive before the boards.
Gotcha. Nice to understand where you're coming from. Still seems very nice of you.
Unclear on whether you already ordered these boards, specifically, or just some other boards. In any case, I would like to go ahead with at least the bare boards (and possibly assembly). Probably 20 boards to have a couple of spares. Any other info I need to provide for the bare boards? Oh, and I am probably fine with spending a little more if it shortens the wait. (= Had been planning to have ribbon cables for all board connections (assuming there is a standard connection), so headers as appropriate.
An update: The form (but not the necessary hardware) has changed a bit. I'm curious whether you think something like this is possible with the current setup:
It's basically just an led matrix with the leds randomly moved in and out along a perpendicular axis (so the image only works from 1 direction). It appears (though is difficult to see) that these lights are simply on or off, which is a limitation of this hardware anyway. My main concerns at this point are overall brightness (I'm under the impression this would be okay), data storage (assume reading from microSD card), and achievable frame rate as controlled by an Arduino.
Searches for frame rate calculation bring up a lot of your old posts (you've been busy). In summary:
SPI at 8 MHz (Arduino clocks at 16MHz; MAX7219 can do up to 10MHz)
16 bits per register; 8 registers / chip; 18 chips = 2304 bits for a full refresh
2304 bits / (8M bits / sec) = 288uS for a full refresh
1 sec/30 frames = 33,000uS / frame
120 sec * 30 frames/sec * 2304 bits/frame = 8294400 bits = 1Mb data for a 2 minute animation
This seems to leave plenty of time for reading the data from a microSD card between frames. It also seems to leave enough time that you could drive individual brightness for each pixel with software (outside the current scope, but it's nice to be able to expand.)
Task List:
Build Max7219 boards
Learn to read data from a microSD card
Write software to send data to boards
Create video data files (going to be pretty primitive to start with)
Build crazy hanging LED matrix (a friend is doing this)
Attach LED matrix to boards
A frustration of searching for old info on these led displays is that there are gobs of potentially useful discussions by people planning something similar, but... there are almost no posts of completed projects. It makes it hard to tell how useful the discussion info actually is. The largest project I've seen so far with MAX 2719 is about 8 of 8x8 matrices with scrolling text.
That should be doable. Boards are already ordered. Four 2x16 connectors.
Use ultrabright LEDs, can dim with MAX7219 15 levels of dimming, fine tune with max current limit resistor. Lot of wiring. http://www.king-cart.com/phoenixent/product=RECEPTACLES-SOCKETS+IDC+.1SP+%2526+2MM+SP/exact_match=exact
See # HWS1931 or #HWS14659. Two pins extra.
May have to mount on opposite sides of the board.
Have you looked at Parola library for controlling multiple MAX7219s?
Maybe you can add SD reading to that, update to use SPI for transfers.
Again - nice to hear that I appear to be on the right track. I picked up a couple of MAX7219 kits (w/ 8x8 led matrices) to start looking at the software end of things. While I do have some software background, it has been strictly high-level programming (awareness of hardware-level communication is entirely new to me).
Absolutely tons of wiring. Significant software development also. Feeling ambitious.
When you say "mount on opposite sides of the board", you mean two of the 34-wire ribbons going to top of the board and the other two 34-wire ribbons going to the bottom, yeah? Is this just to de-clutter, or is this dictated by the clearances between headers?
The Parola library appeared to be targeted at scrolling-text only so I had skipped over it. I'll give it a look to see what can be used, thanks. I had hoped that reading files efficiently from SD would be more or less plug-and-play with existing libraries. Clearly I need to start coming up to speed on that as well.
Edit: Wouldn't need the "polarizing bump" on the connectors.
Edit: Awesome that the boards are already ordered. You're fast. I wasn't even sure that I had said "go" yet. (=
Hi I am trying to do the same. I am using WS2812b RGB led with inbuilt controller. I got led strips from a www.alibaba.com.
The thing is those are pretty good. There is no mess of designing PCB and getting it soldered. You just have to connect multiple strips in series or parallel or both depending on your requirement.
Arduino can use Neo-pixel library provided at Adafruit NeoPixel Digital RGB LED Strip - White 60 LED [WHITE] : ID 1138 : $99.80 : Adafruit Industries, Unique & fun DIY electronics and kits.
I think this is the best solution if one is looking for most simple fastest way to build a RGB led display, rather than going for led multiplexing and all those things.
check out the link bellow. this is where i got the idea.
