Design Example
Greyling LED System
This was an interesting development from 2008/2009.
I was contacted by an aquarium distribution company inside the US. He asked me to help him make a new line of aquarium products for his business. If I wrote the name of the company here, those in the hobby would recognize it immediately.
We collaborated for about 10 months on this design approach. At the time this was my most ambitious design yet, and I called it "Greyling".
This is a circuit board based design which employes FR-4 copper clad circuit boards to become the structure, the thermal heat sink, and the electrical circuit for a unified, lightweight, all in one compact product.
We were making pretty good progress. The light still had some challenges ahead but the preliminary results looked promising.
I relocated myself and my company out of Thailand to China where another one of his vendors manufactured protein skimmers (another large product line in the aquarium business that all hobbies would recognize by name). After that point, he pressed me to remove my brand name from the circuit boards -- and declined that request. A month or so later -- that deal dissolved and he picked another company from China to handle his lighting needs. Their name was featured prominently on his products (so I was a bit uncertain as to why he demanded the remove of my name from the circuit boards).
Anyhow -- that is business. You can't always predict success even when you plan for it. I think the key takeaway on this lost opportunity is to market products directly to end users if you can. Distributors who talk business deals examine both ends of the supply chain to extract a profit.
Back to the product -- I still have prototypes running at my shop and at the studio from this equipment. The test of the elements for this design continues even after a full 10 years. We learn a lot from this work and its "board to board" connection approach.
This system is powered by an AC to DC power supply which provided 12V at about 10 amps -- making this system about 120 watts.
The linear drivers are modular and plug into the board by hand. Each driver PWM (pulse width modulated) current at 350mA. These drivers are very reliable but not super efficient. These drivers are current amplifiers and are driven by Darlington Power transistors. They had some advantages in certain instances, but we don't recommend these drivers anymore. Today -- many years passed this design -- we opt for other better classes of drivers which have become economically more feasible in recent years.
The LED modules are the first ones that I have ever seen (back at this time) that were modular and could be changed by the customer without soldering. All the LED modules are bolted into place with stainless steel nuts and bolts.
Almost any single die, premium brand LED could be fit into this system... Lumileds, Cree, and many others were fit and tested on modules seen in this picture. We tested the Luxeon Rebel and the Cree XP series. The LEDs ran relatively cool and the thermal efficiency of the copper boards proved to be successful.
However, the attached optic from LedIL did not test out so well, because the glue would always fail around the 3 year mark.
The board was controlled by a modular 8-bit microcontroller. We were looking at adding wireless control but that was not completed by at the time of development.
The prototype also had a distributed fan cooling system that was trigger by temperature.
This product has control of 4 separate color channels.