Waiting for components…

Actually, most of the components are in already. A small shipment from Mouser will arrive soon and I still have enough conductors to build 20  shields. More are on order and will here within 2-3 weeks.  As with the ones needed for the prototypes I have not been able to find these at any source her in the US so I sourced them again  from the UK through Allied Electronics / RS components.

I’ve also decided to invest in a laser-cut stainless steel stencil from Stencils Unlimited. The mylar stencil from Pololu.com was fine for the prototypes and likely would have lasted a good number of boards longer but the print quality of a stainless steel stencil is simply better and more consistent. Also of course a SS stencil is much more durable.

Another project I have been working on is a micro controller project  with the aim to have “something” that can take advantage of the capabilities of this LED shield. One of the unique features of this shield is that it is controlled through the I2C bus. All components on the LED shiled (with the Exception of the temperature sensor) are FM+ capable. The FM+ specification allows I2C bus frequencies of up to 1MHz. Instead of 3mA FM+ components can drive 30mA, which allows much longer connections between I2C components. On the other hand most normal Arduino’s allow max 400KHz.  So here is the Frankenduino I’ve described in a previous post:

IMG_2379_small

It features an I2C bus extender based on the PCA9600 chip from NXP. I’ve successfully used a shield on 5 meters of CAT5 Ethernet cable and on my oscilloscope signals looked crisp even at 1.5MHz, so there is quite a bit of headroom to use even longer cables and more devices such as the shield.

Also, what can’t be seen on the Photo is a IR receiver and the Teensy3 happily receives and decodes IR signals from my Apple Aluminum remotes.  A nice feature of the Apple remotes is that they can be paired to a device. I have not quite yet finished the code but I have determined the codes that the remote uses to be paired. However,  before I do that I need to make a second prototype, which features an SD card slot for permanent data storage. It would not make much sense to having to re-pair a remote every time the micro controller has been powered down.

In order to function together with the I2C bus extender I also re-designed the little Arduino I2C extender board. It has SMD pads for different pull-up resistors and also needs a small Schottky diode when operated in conjunction with the PCA9600 I2C bus extender. Below is a picture of a “complete” system, including a micro controller, WiFi Ethernet Hub for remote control ability through OSC / TouchOSC  and a LED shield with the I2C extension board. More shields can simply be daisy chained onto each other using inexpensive pre-configured CAT5 Ethernet cable.

IMG_2392_small

Another interesting idea I had is that it could be quite useful to expose all the functions of the LED shield through the OSC protocol. That way you could create LED effects code directly from a computer e.g. with MaxMSP or Pure Data without having to program the micro controller.

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About trippylighting

Mechatronics Engineer

Posted on October 23, 2013, in Uncategorized. Bookmark the permalink. 19 Comments.

  1. Will this be able to run in boost mode? I have 12V car battery that I would like to run 4 30W RGB LEDs in parallel? They are rated for vf of 28-34V. I am really interested but I need to be able to boost not buck.

    • Hi Chris,

      No, unfortunately this shield cannot be operated in boost or buck-boost mode.
      It was designed for maximum efficiency and maximum dimming range. If you describe your application in more detail, perhaps we can find an alternative solution. What are you going to illuminate with these monster LEDs ?

      • They will be underwater boat LED lights. I live in Florida off the Gulf of Mexico. The waters here can be murky and high lumens is desired, hence, the 30W. I want to be able to drive the RGBs off of an Arduino so I can create custom light shows. I plan to create the lights with a heat sink encased in thermally conductive epoxy. Being underwater should help heat dissipation. Really looking for a good solution as comparable lumen LED underwater boat lights run $800 to thousands of dollars for a single light. Really appreciate the feedback.

  2. Would it be possible to simply alter the design to perform in Buck-Boost or Boost mode? I have been doing some research on it as I am new to LEDs and read it would run at 200mA per channel in Buck-Boost or Boost. I am tryiing to determine what that would do for my light output.

    What would entail adjusting the schematic to run in buck-boost or boost mode?

    • Hi Chris,

      re-designing the shield to work in Boost or Buck-Boost mode would not only require an almost complete redesign, but it would also likely not meet the design goal for your system. However something you may want to consider is using an automotive Boost converter to boost the Battery voltage once and then you could still use the shields and the 30W LED’s at their full 700mA current. That is also possibly more energy efficient.

      If I’d design a boost shield I’d likely use a different chip anyway, such as the LT3476.
      A lot of higher end LED’s such as the LZC-03 or the LZ4-04 from LED Engin are not RGB but RGBW LED’s

      Another thing you may want to take in consideration is the mechanical/thermal design of your system. Underwater systems usually have to have an IP67 if not an IP68 rating. Also, saltwater is particularly corrosive, so encloses are usually made of 316 Stainless Steel or hard anodized 6063 Aluminum.

  3. Thank you for the feedback. I thought about boosting the voltage once but became engulfed in the LED Driver discussion. I am aware of the design of the corrosion and IP ratings. Would there be an advantage/disadvantage of a higher watt boost converter than 300W?

    Are you taking advanced orders for the LED Shield? To operate 4 30W RGBs, I would need 4 stacked correct? Also, would integrating a xBee for wireless control of the LEDs be possible with your shield?

    • Hi Chris,

      I would not think that there is a advantage to a bigger boost converter unless you are going to run other things in addition to the LED’s.
      One thing to consider is that when running light shows with constantly color fading LEDs you will never run each LED at 30W, so there is plenty of headroom when using a 300W boost converter.

      Yes, you can definitely use an xBee in conjunction with the LED shield. The LED shield really only uses only the two I2C pins pins and GND on the Arduino that should not interfere with any of the xBee modules. If you stack one or more shields to an Arduino you can power the Arduino from the LED shield using one more pin (+5V) and don’t need an extra power supply only for the Arduino.

      Yes, you need 4 shields, one per RGB LED. You could stack all shields onto an Arduino, but I’d keep the shields as close as possible to the LED’s. That’s where the I2C bus comes in handy as you can keep the Arduino in a central location and connect the shields to the Arduino using fairly long cables.

      I am not per-se taking orders yet. I have received all components except the Inductors. I am thinking that sometimes in the next 2-3 weeks I will have a first batch of these shields available and will then put the boards up for sale at Tindie.com. I’ll inform the few people that have voiced interest through the blog as soon as that happens. Whomever of that set of people orders will receive the first boards. That would include you!

  4. Amazing shield! Great of you to take the initiative and offer your experience to the peple (like me) through this project. I would absolutely love to buy 2 or 3 of these when they become available.

    • Hi Chris,

      Thanks for the comment 🙂
      It should not be too long anymore before I make them available. I’ve received all the components and just need to set some time aside to build them. With a little luck I should be able to build a first batch within the next two weeks.

  5. Hi, can you please explain how to connect arduino mega + ethernet shield to WR-702N router. I have trouble in configuration…

    • I can, but I am afraid you’ll have to be a good bit more specific as to what configuration problems you have.
      I don’t use Arduino btw.
      In fact, I really only have an Arduino Uno around as a baseline configuration. For my real projects I use Teensy3.

      • I want to connect arduino mega to a web server. I can do that using ethernet shield. But, I want to do this wireless using wr702n router.

  6. Just checking in to see if there are any updates on the status of the shields.

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