Comments on: Rainbowduino fun — aka neorainbowduino

By: michu

michu — Thu, 23 Dec 2010 07:24:32 +0000

hey greg. the original “gamma correction” was done by displaying the first brightness level longer then the 2nd brightness level etc. I didn’t like that and choose to use a gamma lookup table (its in the java library: http://code.google.com/p/neorainbowduino/source/browse/trunk/processingLib/src/com/neophob/lib/rainbowduino/RainbowduinoHelper.java). With this map you can improve the coloring (the comment from the blog entry: PWM from 0 to 100% duty cycle is accurately changing brightness in a linear way, the eye sees almost no difference between 75% and 100% brightness).
And I guess you cant use more than 16 color level per channel — as this is a hardware limitation. I didn’t try it though.

By: gregf

gregf — Thu, 23 Dec 2010 03:22:19 +0000

hi, nice library. your firmware for the rainbowduino is clearer to me than the other ones I’ve found so I can actually try to understand what is going on and try to program my cube to do something interesting.

I’m curious, how does gamma correction work with your firmware? i can’t find a reference to it in the code.

also, any idea how to use more than 16 color levels per channel? the colors step noticeably for me.

By: michu

michu — Sun, 21 Nov 2010 13:04:28 +0000

I also had some issues with arduino’s twi lib, the interrupts disrupted by display function if too much i2c data were send. however I worked around this issue by limiting the data I send to the device — I send only changed frames to the device (using md5 checksum). To send an RGB image to a rainbowduino currently takes about 20ms — so per arduino I can send out 50fps. I save about 50% using my checksum function, means you get “virtual” 100fps.

By: jbremnant

jbremnant — Sat, 20 Nov 2010 16:14:18 +0000

Wow, this is cool stuff. Great job. I followed the breadcrumbs back to your blog after seeing your comment. How many fps can you get with this set up?

A bit about arduino’s twi lib — it is interrupt based implementation which I found to be rather inconsistent when I tried to use it on barebones atmega chips. I had it working with Wiinunchuck, but it was pain to get it working. This thread has some good info:

http://www.nerdkits.com/forum/thread/972/

If you don’t mind doing s bit of C coding outside of arduino IDE, i recommend: http://homepage.hispeed.ch/peterfleury/group__pfleury__ic2master.html

This one uses polling mechanism and discard interrupts all together.

By: neophob.com » Neorainbowduino Processing Library

neophob.com » Neorainbowduino Processing Library — Thu, 16 Sep 2010 20:53:39 +0000

[…] for each rainbowduino! Upload the Arduino firmware to you Arduino, wire up the whole stuff (check my last post about neorainbowduino how to connect the […]

By: Andy232005

Andy232005 — Mon, 13 Sep 2010 09:32:30 +0000

Thank you I did install eclipse last night I’ll follow some tutorials to get me started I’m looking forward to playing with the rainbowduino using my laptop Thanks for your help.

By: michu

michu — Mon, 13 Sep 2010 06:02:07 +0000

Currently you need to use eclipse, as my processing plugin is not yet finished. You need to use some Processing libraries and the serial libraries (librxtx).

I’ll provide some examples, once I’ve finished the processing lib.

regards

By: Andy232005

Andy232005 — Mon, 13 Sep 2010 02:11:05 +0000

I’m really new to anything java and still don’t understand sorry. I’ve got a rainbowduino hooked up to my arduino with everything ready I want to stick to what your doing as your active I see your updating stuff on google code all the time. Do I need a java ide I don’t know where to write that code Please help me

By: michu

michu — Sun, 12 Sep 2010 21:39:53 +0000

hey

to initialize the rainbowduino device, use

1
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5
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private Rainbowduino rainbowduino = null;
private boolean ping;
…
rainbowduino = new Rainbowduino( papplet );
rainbowduino.initPort();
ping = rainbowduino.ping((byte)0);

then send a frame to the rainbowduino:

1	rainbowduino.sendRgbFrame((byte)i2cAddr, THE_8x8_BUFFER, false);

cheers

By: Andy232005

Andy232005 — Sun, 12 Sep 2010 21:09:00 +0000

hello can you help me please I don’t know how to run rainbowduino.java I’ve done as you said but now i’m stuck

By: mel.o

mel.o — Sun, 18 Jul 2010 23:25:02 +0000

OK look. I’m an artist, I have cool ideas to do for rainboduino but I don’t have the head for all these complications. I just want to tell each led what color to be, how bright, and for how long. Is that too much to ask? How much would I have to pay you to set it up for me?

By: Fancy animations made by Rainbowduino | Seeed Studio

Fancy animations made by Rainbowduino | Seeed Studio — Mon, 12 Jul 2010 05:34:17 +0000

[…] the resources and codes you need to make the same effect, click below link for the original post: http://www.neophob.com/2010/07/rainbowduino-fun-aka-neorainbowduino/ VN:F [1.9.3_1094]please wait…Rating: 0.0/10 (0 votes cast)VN:F [1.9.3_1094]Rating: 0 (from 0 […]

By: michu

michu — Thu, 08 Jul 2010 14:36:04 +0000

Thanks! It’s fixed now.

By: Icing

Icing — Thu, 08 Jul 2010 14:27:44 +0000

The title of
4) Update Arduino Firmware
and
5)Update Rainbowduino Firmware

should be exchanged.

By: Tweets that mention neophob.com » Rainbowduino fun – aka neorainbowduino -- Topsy.com

Wed, 07 Jul 2010 16:44:33 +0000

[…] This post was mentioned on Twitter by Vincent van Haaff, Tech news (BOT). Tech news (BOT) said: Reddit/p: 2x rainbowduino with a rgb led matrix + 1x ardiuno + some java code = shitload of fun! http://bit.ly/d4plGS […]