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46  Using Arduino / LEDs and Multiplexing / Re: Driving 750 or so leds, independently (of Course....why should this be easy?) on: December 26, 2013, 11:28:41 am
What speaks against using several length of LED strips instead of single LEDs ?

Using a Teensy3 or Teensy3.1 and the OCTOws library you can use thousands of LEDs at video refresh rates. The biggest project posted so far on the Teensy forum used in excess of 10000 LEDs in form of WS2811 led strips.
47  Using Arduino / LEDs and Multiplexing / Re: Very high powered LED's dimming - n00b on: December 26, 2013, 11:14:18 am
What you needn't addition to the LED(s) if you are going for a DIY product are four main components:

Power supply
Heatsink - available at eBay as well
Microcontroller - Arduino or compatible too  control PWM for dimming.
Constant  Current LED driver

There are heaps of el-cheapo Chinese products available on eBay with no documentation, total lack of competent or any customer support. There are several constant current drivers available on and also a few  Arduino shields that can be stacked directly onto an Arduino. Which one you use depends on your specific application.
48  Using Arduino / Project Guidance / Re: Wireless Surveillance System on: December 24, 2013, 06:50:34 am

Or give me example code for my project.
What part of your project as YOU going to do?
So plz give me code for this purpose. Thank You,
You know, this is a DIY forum. DIY stands for Do It Yourself. Start writing some code and when you encounter problems and things don't work as expected/ intended, then we'll help. The information you've provided is not detailed enough to write much more code than PaulS already has provided above ;-)
49  Using Arduino / Networking, Protocols, and Devices / Re: I2C question on: December 14, 2013, 04:27:56 pm
The data sheet states that the device uses a simple serial interface compatible with the SPI protocol. Why are you using I2C ?
SPI runs at much higher frequencies than I2C and can transfer much more data. Alas ofer shorter distances.
50  Using Arduino / Networking, Protocols, and Devices / Re: serial to osc on: December 14, 2013, 04:20:06 pm
Yup. I've come across the same problem when trying to connect TouchOSC to an Arduino ( well actually it was a Teensy3).
TouchOSC only receives and sends OSC messages and not OSC bundles.

Also, the library had a memory leak that had me scratch my head for a while but has been fixed in the meantime. You may want to download a fresh copy from The OSCuino GitHub site.
51  Using Arduino / LEDs and Multiplexing / Re: How to use a high current PWM LED controller on: December 14, 2013, 04:07:17 pm
This shield uses the powtec PT4115 LED driver. It is directly connected to the Arduino PWM pins. As GrumpyMike said, the AnalogWrite function will do for PWM dimming. Having that said, however, that leaves to be desired. The PT4115 has a dimming ratio of 5000:1 easily enough for 12bit dimming but the Arduino pins only allow 8- bit, at least in the AnalogWrite function.

There are ways to get some of the pins to dim at 16 bit, but I am not sure if that will work for all 6 PWM pins.
If you use both shields on the same Arduino Mega ADK you'll still only be able to control 6 independent channels, not 12 as both shields will use the same 6 PWM pins.
52  Using Arduino / Microcontrollers / Re: Which controller to take for 3x16bit PWM? on: December 03, 2013, 11:06:09 pm
A Teensy3 is $19 is much smaller than a normal Arduino and has 10 16-bit hardware PWM pins.
53  Development / Other Software Development / Re: Windows/Linux/Mac Eclipse plugin to compile and upload arduino sketches on: November 14, 2013, 09:18:18 am
Yes, unfortualately that is the case. It did not occur to me that you were using a Yun until after I posted.

The Yun is supported with the elease of Arduino 1.5.4 but the Arduino team also introduced changes, e.g. how libraries are supported that make it very difficult for third party developers to support the Arduino environment. This does not only concern Eclipse but there are others.

While these third party developers (software as well as hardware). The very well thought out suggestions these third party deveopers have put forth have been met with a surprising reluctance, despite the obcvius shortcomings of the IDE.

Anyway, if you currntly want to use the Arduino Eclips Plugin with an Arduino Yun you are at an impass as the eclipse plugin does not with with the 1.5.4 Arduino environment.

Do you get this message also using the Arduino IDE when runnning on a Mac natively ?
"Connecting to programmer: .avrdude: butterfly_recv(): programmer is not responding
Do you get this message "

54  Development / Other Software Development / Re: Windows/Linux/Mac Eclipse plugin to compile and upload arduino sketches on: November 13, 2013, 11:51:55 am
To add to Jantje's comments, there is really no reason to use Arduino and Eclipse + Plugin in a VM on the mac.
That combo runs very smoothly natively on a mac. It has been noted that the way the VM assumes the USB ports in some cases
interfers with things.

Here is a link to detailled installation instructions on a mac.
55  Using Arduino / LEDs and Multiplexing / Re: Need more control over PWM for led fade. on: November 03, 2013, 10:48:46 am
I re-read the OPs original post, and in that application when you fade in all color channels from zero that step is detectable, I agree. For the OPs intended purpose I'd agree that the little breakout from Adafruit seems ideal. Had not seen that one before, so thanks for posting it!

56  Using Arduino / LEDs and Multiplexing / Re: Need more control over PWM for led fade. on: November 02, 2013, 05:17:07 pm
Another thing that came to  ind is that if actually do want to use 16 bit, the Teensy3 has 10 pins that can do 16-bit PWM Not bad for $20!
57  Using Arduino / LEDs and Multiplexing / Re: Need more control over PWM for led fade. on: November 02, 2013, 05:04:16 pm
The steps come from a nonlinear response of the human eye to changes in brightness.
If an LEDs light output would be by some strange coincidence matched to that, 256 steps or 8-bit per color channel would provide you with smooth dimming.
The article here explains this fairly well. In order to linearize it is fairly common to use a lookup table that maps the 256 steps onto a 12-bit map.

I use that approach in my lighting systems ( see signature for links) and it provides very smooth fading using 265 steps per color channel. Only when fading very, very slowly at ranges vevery close to zero have I been able to detect steps. So in essence the speed which with you fade also has to do with the ability to detect steps. Having 12-bit dimming available I can still use a 10-bit lookup table to correct that behavior.

16 bits are nice if you want to use arbitrary scaling, say if you want to be able to only use only a quarter of the dimming range of your LED but still want to be able to smoothly fade, however is not really necessary at all in my experience. More is not necessarily better!
58  Using Arduino / LEDs and Multiplexing / Re: 10 Watt high power LEDs. on: October 31, 2013, 03:12:59 pm
I was merely pointing out that there was a technical inaccuracy in what you wrote and did want to point it out as it has been a misunderstand in more than one three/post on this forum. No reason to be defensive!

I am not sure I understand your problem not being able to draw enough current. You wrote in a post above that you are using current limiting resistors that will limit the current through the LEDs to 400mA. When you set the duty cycle of the PWM signal to 100% then the "switches" are on 100% of the time, thus you will draw these 400mA. If you want more current to flow you'd need to lower the value of the current  limiting resistors, or is there something I am missing ?
59  Using Arduino / LEDs and Multiplexing / Re: 10 Watt high power LEDs. on: October 30, 2013, 07:27:25 pm
If you are using current limiting resistors, then you will not damage the  LEDs. However the assessment that with PWM you can perhaps reduce average current but not peak current is still correct.
60  Using Arduino / LEDs and Multiplexing / Re: 10 Watt high power LEDs. on: October 27, 2013, 11:50:51 am
You CANNOT lower the current draw using PWM. You limit the overall energy going into the LED, however, if the current exceeds that of the LEDs spec you may have already shortened the lifetime of the LEDs.
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