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91  Using Arduino / LEDs and Multiplexing / Re: Turning a simple 3w led w/arduino on: April 27, 2013, 12:55:17 pm
Hi Steve,

Welcome to the Forum. Switching a 3w high brightness LED with a linear regulator works but is not recommended. LEDs are constant current devices and that's not really the purpose linear regulators are made for. They also tend to get pretty hot and may require heat sinking.
Also, if you have not mounted a heat sink to your 3W LED now would be a good time!

You cannot switch a 3W LED directly with the Arduino as the pins on the Arduino cannot supply that much current, which is usually in the 350 - 700 mA range.

If you've not found the answer here on the forum then I'd encourage you to search a bit more as this topic has been discussed many, many times.

BTW The best, most efficient way to drive high brightness LED and being able to fade them is a switched constant current power supply that allows PWM control.
92  Using Arduino / LEDs and Multiplexing / Re: RGB LED easy smooth colour transitions on: April 25, 2013, 06:22:35 pm
Any jumpyness in color has nothing to do with the LEDs being common and or common cathode but rather with the fact that only 8 bit are used per color and that the eyes response to light intensity is not linear.
@OP I've seen this algorithm referenced in another post fairly recently, but the poster did not quite understand it. If you've reinvented this from scratch kudos to you!
93  Using Arduino / LEDs and Multiplexing / Re: LED driver shield on: April 23, 2013, 06:00:02 am
That is quite a massive tank!
It looks like you are trying to directly compare the lumen output of a metal Hali lamp with the lumen output of LEDs. Traditional lamps, including metal halide, distribute their light ove a much steradian, thus the need for large reflectors to collect all that light.
LEDs distribute their light much more dictional and with appropriate TIR optics are able to direct their light output with much higher optical efficiency. So light output per steradian - light density - is more important than overall lumen output.
94  Using Arduino / LEDs and Multiplexing / Re: LED driver shield on: April 23, 2013, 05:33:16 am

I've never did anything with LEDs before so I'm still trying to learn...I don't think this driver shield is gonna be enough for my needs,looks like 36 LEDs will be the max I could use without stacking about 4 of those shields...I appreciate the help


Your setup with this shield should put out  at least 4000 lumens ( the blue LEDs usually have a lot less output than the white LEDs). That is extremely bright! No need to stack 4 of those together!
If you really need more lumen output you can also try to find LEDs that run at 1A max instead of the 700mA as these should have a higher lumen output.
95  Using Arduino / LEDs and Multiplexing / Re: 3W Dimmable LED Driver DC 7-30V 700mA on: April 15, 2013, 05:49:47 am
Quote
Perhaps you start reading and understanding the alnalogWrite sample http://arduino.cc/en/Reference/AnalogWrite provided on the Arduino website. The code you posted above is missing an essential line in the setup that configures your pin 3 as an output.
Headroom, there's no pinMode missing, if that's what you're implying
Yup, that's what I was referring to. Guess I need to do my own reading  smiley-lol

@OP
The LED driver you are using employs a PT4115. The data sheet recommends an input voltage of 6-30V and has an under voltage lockout of 5.1V. I have used three of these http://www.ebay.com/itm/high-efficient-led-driver-0-35-and-0-7-and-1A-good-use-Arduino-/370632520478?pt=LH_DefaultDomain_0&hash=item564b6b731e which use the same chip and when trying these out first I had hoped to get by with a 5V wall wart I had handy. Unfortunately at 4.9V it was below the low voltage lockout. When I used a 9V Wallwart things started working as expected :-)
96  Using Arduino / LEDs and Multiplexing / Re: 3W Dimmable LED Driver DC 7-30V 700mA on: April 14, 2013, 10:06:44 am
Perhaps you start reading and understanding the alnalogWrite sample http://arduino.cc/en/Reference/AnalogWrite provided on the Arduino website. The code you posted above is missing an essential line in the setup that configures your pin 3 as an output.

Also, you may want to urgently mount your LED to a heat sink with some thermal tape, thermal epoxy or screws and thermal paste. If the LED gets the full 700mA for too long it will overheat and that will dramatically reduce its lifetime!
97  Using Arduino / LEDs and Multiplexing / Re: High Power (Brightness) RGB LED shield on: April 10, 2013, 06:32:51 pm
Buck configuration.
98  Using Arduino / LEDs and Multiplexing / High Power RGB LED shield - 12bit/channel dimming - I2C (TWI) on: April 09, 2013, 08:58:51 pm
After slowly starting to redesign the shield in January I now have a functioning prototype and I am considering having a batch of these either manufactured or possibly manufacturing them myself.But lets take a little step back.

I used a number of five of a previous version of this shield in my own LED lighting project (trippylighting.com). The maker of the original shield sold these through his blog. The last entry on the blog is from Dec. 2012 announcing a christmas break and while there have been a few answers in response to inquiries on the blog he has not posted anything in over 9 months and appears to have lost interest in his creation.

Much to my dismay as I was hoping to use these in a few more projects. When it seemed a possibility that the blog would go offline another user of the shield created another blog and pulled all the information over so it would not be lost.
He invited me to co-host the blog and I accepted. We discussed having a batch of these manufactured in their original form, but as I started creating a costed BOM it became clear that the original Inductors would not be available anymore and we had to find alternatives.

Also there were a few things that I wanted to change and as one thing lead to another...
You can read more details here on our blog: http://ledshield.wordpress.com.

So let's quickly go through the Features the shield has to offer:

  • Three independent constant current channels. This shield will NOT operate common anode or common cathode LEDs!
  • Meant to drive high brightness LEDs with a constant current from 350 to 700mA.
  • 42V input. 36V output can drive up to 40W of LEDs.
  • On-board 5V switching power supply and I2C connectivity provide for standalone operation.
  • Shield stacks on top of an Arduino but can be operated independently as it only uses GND and I2C (SCA,SDL) from Arduino.
    Shield is stackable (also in multiples) onto Arduino Uno (Rev 2 and Rev 3) and Arduino Leonardo but can be
    connected and operated from any other Arduino Board or microcotroller platform that offers I2C.
  • 12bit PWM resolution per channel allowing for CIE lab brightness corrected dimming(library function).
    The 12bit PWM in conjunction with the LED driver chip provide a dimming ratio of 3000:1 and more.
  • Dynamically adjustable constant current (I2C) between 100mA to 700mA allowing for analog dimming.
  • Adjustable/programmable (I2C) PWM frequency 40Hz to 1.6kHz
  • On-board I2C pull-up resistors can be disabled by means of solder jumpers.
  • Shield is stackable onto Arduino Uno (Rev 2 and Rev 3) and Arduino Leonardo but can be connected and operated from any other Arduino Board through I2C.
  • Optional temp sensor to monitor led temp
  • An Arduino library that provides access to all functions is available on Github.

If all that sounds attractive, please come over to to our blog http://ledshield.wordpress.com and leave a comment if you're interested.
The original price of this shield was US$41.50 and we hope to keep it in that range, but that obviously depends somewhat on quantity.
  
The posted image is a prototype and a few minor refinements are needed, e.g. all the Arduino Pin labels are missing. The terminal block for power input (5mm pitch) is too tall to allow stacking multiple shields and will be exchanged for a smaller one (3.5mm pitch).

99  Using Arduino / LEDs and Multiplexing / Re: OctoWS2811 Library - for large LED display at video speed refresh on: April 01, 2013, 05:25:56 am
What you're looking for is not Gamma correction, but CIE lab brightness correction, as the article at neuroelec.com explains. However, the difference is relatively small and I am not sure if its visible.
I have a 12 bit version of it that I coupled post, and ther is also an 8 bit versioning the forum.
However, you can expect the 8 bit a bit ... Choppy.. At lower intensities due to limitation of resolution.
100  Using Arduino / LEDs and Multiplexing / Re: Random RGB Values Give Pastel Colors on: March 30, 2013, 08:28:29 pm
I actually have to revise what I had stated earlier. Clamping one of the values to 255 is not going to work. The way the rings are generated in my lighting system is that the optics in fromt of the LED head " clamps" one of the colors to zero.
So in essence if your algorithm chooses one of the three channels to clamp to zero and then you choose values randomly for the other two channels it'll work better.

However, the approach fungus has posted, selectin HSV and conveting it to RGB - while more complicated to implement and more computationally expensive - is by far the best approach!
101  Using Arduino / Networking, Protocols, and Devices / Re: Arduino WIFI on: March 28, 2013, 05:31:33 am
Somehow you missed at least  half of what I wrote  smiley-confuse I am not familiar with the ArdWiFi shield. Are you speaking about this device : http://www.csdrobotics.com/controller%20boards/images/ARDWIFI%20Manual.pdf ?

It looks to me that the WiFi module on that shield does NOT employ the WizNet W5100 WiFi chip from WizNet. So in essence, you''ll have to retire the ArdWiFi at least until you have a good bit more Arduino experience. Instead you need to get an Arduino Ethernet Shield. This one:
http://arduino.cc/en/Main/ArduinoBoardEthernet. You can get these relatively cheap at eBay for $20. A new original shield from Sparkfun   https://www.sparkfun.com/products/9026 will be about $45.

Then you need to obtain a TP-Link TL WR702n wireless router: http://www.tp-link.us/products/details/?categoryid=&model=TL-WR702N for example at Amazon http://www.amazon.com/TP-LINK-TL-WR702N-Wireless-Repeater-150Mpbs/dp/B007PTCFFW/ref=sr_1_1?ie=UTF8&qid=1364465095&sr=8-1&keywords=tp-link+702.

As an alternative if it has to be a WiFi shield you could get the WiFly shield from Sparkfun https://www.sparkfun.com/products/9954. Through two libraries - namely WiFly HQ https://github.com/harlequin-tech/WiFlyHQ and Ad=rdOSC for WiFly HQ https://github.com/Zapalot/ArdOscForWiFlyHQ this may support OSC but I have no personal experience with this hardware and cannot vouch for its function.

Once you have these devices (Ethernet Shield and router), let's continue the conversation.

The Ethernet library is !very! unlikely to work with your particular WiFi shield. It is meant to work directly with the original Arduino Ethernet shield that I've linked to above. The Arduino Bonjour library (that you can actually live without) relies directly on lower level functions of the Ethernet library. Any response you may have gotten from your WiFi shield does not involve any of these two libraries as they are hardware dependent on the presence of the WizNet W5100 chip.

Both, the ArdOSC library and the iOSCController library require the Ethernet library/shield.
102  Using Arduino / Networking, Protocols, and Devices / Re: connect an arduino to a server DNS/DHCP on: March 27, 2013, 08:16:49 pm
You may want to talk to the network admin of your school if that is even possible and if they'd allow it.
I could imagine plenty of reasons why they would not allow it ;-)
103  Using Arduino / Networking, Protocols, and Devices / Re: Arduino WIFI on: March 27, 2013, 08:14:03 pm
I Re- read your post. It appears that you had problems even for the iPhone to pick up the Arduino WiFi shield. This may also be an outdated statement but at least in the past the Arduino WiFi shield relied on ceiling an IP adds through DHCP from an existing WiFi router and then you could connect to the WiFishield through the router.

The Ethernet <-> TP-Link router does not have that problem. The router comes configured as an AP (Access Point). You plug it in and can connect to it right away with the iDevice of your choice!
104  Using Arduino / Networking, Protocols, and Devices / Re: Arduino WIFI on: March 27, 2013, 07:59:17 pm
I am afraid you've bitten off a bit more than you can chew at the moment, but don't despair.

You are missing a whole lot more than a few basics and I can say that because I've made this work and had to learn a few things the hard(ware) way.

My current state of knowledge about the Arduino WiFi shield, or better the current set of libraries do not yet support the UDP protocol and there have been a numer of posts about this unfortuante fact on the forum. But that may be different now. That is important because the OSC protocol generally is based on UDP and ArdOSC is no exception.

If the Arduino WiFi shield does support UDP, you have another few hurdles to take. ArdOSC makes use of some lower level functions of the original Ethernet shield library that talk directly to the W5100 Ethernet chip on the Ethenet Shield through SPI. You'd have to rewrite these functions for the specific hardware of the Arduino Wifi Shield.

The above are most of the hardware limitations. There is one more that has to do with the memory requirements of the involved software libraries so an Arduino version with more memory, e.g. a Mega would work if you need space for your own code.

However, you can deal with all of the above if you are not shy of getting different hardware. E.g. Get an Ethernet shield, so you can work with ArdOSC right out of the box. If you want WiFi, then connect a little pocket router to it. I've used a TP-Link TL WR703n and a 702n. I'd recommend the 702n as it has a English user interface (if you buy it through regular US sales channels) the interface for the 703n is all Chinese. You can get the Ethenet shield on eBay for about $20. As long as it has a W5100 chip on it you should be OK. The router will set you back about $25. Together, IMHO that provides you with a lot more mature functionality than any of the WiFi shield currntly available at a much petter price point.

The next thing you are missing is that the reason services show up in TouchOSC is because these are services that are announced through Bonjour http://en.wikipedia.org/wiki/Bonjour_(software)
For TouchOSC to pick the Arduino up, you need to use the Arduino Bonjour library to register a service on the WiFi network that your iDevice is connected to.

BTW, the Bonjour Library also makes use of some lower level functions of the Ethernet shield library!

In my LED lighting systems instead of an Arduino I use the Arduino compatible Teensy++2 http://www.pjrc.com/teensy/with a WIZ812MJ Ethenet module http://www.saelig.com/BRD/ETH042.htm and adapter also from PJRC. Together,  including the router, all that is less expensive than the Arduino WiFi shield alone!

So, if I have not severely scared the crap out of you and you still want to go ahead with your project and are not afraid of occasionally pulling out your hair and are ready for a few setbacks, in that case you are in the right ace here and I'd be glad to help you along. Once it starts working its actually pretty darned cool!!!

Perhaps start with what you actually want to achieve as an end result and  we'll go from there.
105  Using Arduino / LEDs and Multiplexing / Re: Random RGB Values Give Pastel Colors on: March 27, 2013, 05:53:27 am
Mike is correct, it does help  smiley-wink

This trippylighting.com ( scroll down to the video) does exactly that. It randomly chooses 3 values and then clamps one of them to 255 and then fades from the last set of randomly chosen values to the new set.
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