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greeeg

120 LED Ring Clock

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Hey, It's been along time since I've posted. but I've been keeping busy with uni and working on some cool projects for the last year.

 

This is something I'd like to share with you guys, it's not finished yet but the hardware is more or less complete. It is an RGB LED ring clock.

 

post-274-0-23665900-1389581215_thumb.jpg

 

The clock is comprised of 2 rings of 60 LEDs each. the LEDs are WS2812 parts, which include a built-in driver.

 

The PCB is one of the interesting parts of this clock. I designed the board in altium as a single 6 LED segment. and then left pads at each end to allow them to be soldered onto another segment.

 

post-274-0-78384000-1389581361_thumb.jpg

 

Using seeed's 10pcs PCB program I was able to create the full ring.

 

Currently I am using a MSP-EXP430FR5739 board to drive it, using some very in-efficient assembly code that requires a 20MHz clock.

 

I'd like to optimise the code to use an internal SPI module? or timer to bring that clock speed down.

Hopefully also design a control segment with LEDs on one side that could replace one of the current segments in the ring.

 

post-274-0-55251500-1389581549_thumb.jpg

 

 

Edit: I've built up a simple controller based on the G2121. yes, 1kb Flash, 128b of RAM!

 

I decided to test my asmebly skills and use naken430 the msp430 assembler. Here is my code

G2121_ledRing.zip

 

I also added a ring of perspex to help difuse the LEDs

 

Here is a video of the clock in action.

http://www.youtube.com/watch?v=tBCvR4BA7pw

 

 

edit: 06/03/14

Version 2_02!

Major differences:

  • "double" so you need only 5 pcs to make a full ring, the pieces fit in 5x10cm
  • Uses new 4 pin WS2812b parts

post-274-0-47604100-1394117248_thumb.jpg

 

PCBs arrived, been tested and is functional, but has some very small issues.

Known Errata:

  • Doesn't account for very small milling tolerance, means small gaps at joins
  • No silkscreen for LED footprint, only shows orientation
  • Edge connectors a few mm from the edge.
  • Vias connecting to pour have star connections, should be direct connection
  • Thin soldermask trace around OSHW logo is to thin
  • 1 LED under OSHW logo isn't concentric with the rest of the LEDs (<1mm off)

 

 

There is also a special controller board in the mail, this will be tested and documented when it arrives.

 

edit 2/06/13

Please see this project for lot of photos and additional information about version 2_02

 

Version 3!

post-274-0-59309200-1401690880_thumb.png

  • Boards have been designed, and I have some prototypes on the way. Designed mainly to upgrade the MSP430 used in the last design to a more capable one. 
  • Boards arrived
  • Some small errata found, pads to small for regulator, JTAG pins in wrong order.
  • New board has been design to fix these issues.

There is a tindie page where you can register any interest in buying.

https://www.tindie.com/products/Greeeg/ledring-clock/

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It's terrific and I love the modular design.

 

I could imagine it looking very expensive in a sleek case, or mad scientist style with all the wires and guts hanging out of the middle.

 

What do those WS2812s cost in quantities of 120? 

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I could imagine it looking very expensive in a sleek case, or mad scientist style with all the wires and guts hanging out of the middle.

 

What do those WS2812s cost in quantities of 120? 

 

Thanks :)

 

I'm thinking of MDF wood. in a ring shape to cover the PCB and have the LEDs bounce off the wall.

 

Just bought them via ebay.

I got 200 for $45 USD, so that makes 120 come out to $27.

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Not bad. Anyone interested in a group buy?

 

From what I've seen, (only via ebay tbh). You get free shipping. I think that any price benifit from a group buy would be lost on the shipping charges involved with a group buy.

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Perhaps you're right. A cursory look on Taobao suggests they can be had for 0.70 Yuan, or about $0.10, so perhaps not sufficient saving to make it worthwhile unless the volume discounts are pretty large.

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@@greeeg I'm still trying to figure out how you attach them? Any more close up shots of this?

Thanks!

Push them together then create Solder bridges on the four different traces/pads on the edges.

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Yes, cde is right Bluehash. I have 4 SMD pads on each end of the modules. I used 2.54mm headers removed from the plastic to solder onto these pads to create a strong connection.

All of the pads also have a via in them to reduce the risk of breaking off from the PCB.

 

The wires on the picture are the power +5v and GND and the signal line to control the LEDs.

post-274-0-02621400-1389747062_thumb.jpg

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Nice project! Been thinking about something similar myself.

 

One tip regarding the LED's: the newer WS2812B has only 4 instead of 6 pins which means 240 less solder poinst for this clock. Other improvements (according to this post)

  • simpler layout helps prevent shorts
  • improved voltage drop
  • improved thermal dissipation
  • higher brightness

I've found these in lots of 200 at AliExpress for $30 plus $20 shipping.

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