Home
Projects
RGB LED RING V2

Featured User: kurt

Open-source hardware project hosting is my passion. I spend most of my free time building neat gadgets or planning what I'll build next. I love building things, and I want to make Open Hardware Hub a place that inspires others to build, ...

Learn More
Updates 2013 February 18

It's been a while, hasn't it? Well, that's ok because we've got a lot of updates to talk about. Most of these have been effective on the site fora couple weeks now. A few may or may not be active when this article gets posted, but they'll certainly be applied in the ...

Find Out More

RGB LED RING V2

By: madworm

I've updated an old design of an 8-RGB-LED ring with dedicated constant current LED drivers and better firmware implementing Binary Code Modulation (BCM), which provides 6-bit depth per color and low cpu utilization and individual control of the LEDs with double buffering. Oh, and it's darn bright!

Download project description w/o images
Download project description w/ images

Files

RGB_LED_TOY-80289ae848025eb0ddf43d037901b7deda3aad72.zip - Kicad design files for the board shown here
rgb_led_toy_test-1f0cb8c0f35aaba925737d89bb67ba0d2534af98.zip -

Download all project files

Bill of Materials

Qty	Part #	Description	Schematic ID	Source
1	ATMEGA168-20AU	8BIT 16K FLASH MCU, TQFP32, 168		Source
3	STP08CP05MTR	STP08CP05 Series 100mA 30 MHz Low Voltage Low Current Power 8-bit Shift Register		Source
3	TC33X-2-202E	TRIMMER, 2K, 3MM		Source
3	CRCW0805560RFKEA	RESISTOR, 0805, 560R , 1%	R3-5	Source
2	CRCW080510K0FKEA	RESISTOR, 0805, 10KR , 1%,0.125W	R1-2	Source
8	VAOS-5050RGB-W1	LED, RED / GREEN / BLUE, PLCC-6	D1-8	Source
1	929836-03-36	Pin Strip Header	JP1	Source
5	08055C104KAT2A	CAPACITOR, 0805, 0.1UF, 50V	C1, C3, C4, C6, C8	Source
1	1206YD106KAT2A	CAPACITOR, 1206, 10UF, 16V, X5R	C2	Source
3	B45196H3106K109V17	CAP TANT 10UF 16V 10% 1206	C5, C7, C9	Source

loading total from bomfire.com...

Download BOM w/o images
Download BOM w/ images

Steps

6. Make it shine!

Assuming the board has passed close visual inspection (no shorts, no misaligned or misplaced parts...) and been cleaned with IPA, it is time to power it up and upload code. It is designed to run at 5V DC with the correct polarity. Also make sure that your USB/Serial adapter is compatible with the 6-pin connector on the board. The signal names printed on the silkscreen will be a guide. An adapter is easily built with some stranded wire and some headers.

You can easily add board-definitions to the IDE for this doodad. Simply append the contents of the 'arduino-setup' folder to the IDE's 'boards.txt' file and restart it. Once that is done, select the board, compile / upload as usual.

The I²C pins (VCC, GND, SDA, SCL) have been broken out to a separate header, so you can quite easily build a network of these boards using the 'Wire' library that comes with the IDE.

Here's a very good introductory article about how the aforementioned 'BCM' is superior to simple software driven PWM in terms of CPU utilization. Definitely worth reading.