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Thread: controlling external LED arrays with Procyon

  1. #21
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    Default Re: Circuit board coming for Procyon interface

    This is all VERY cool!

    Did you ever get to making the circuit boards?

    -Andy.

  2. #22

    Default Re: Circuit board coming for Procyon interface

    Update:

    Started to draw a fully linear circuit board but had a hard time (1) keeping the size of the heatsinks to something reasonable that would account for possible power supplies (e.g., 12V battery), and (2) being "okay" with a significant waste of power.

    While exploring switched power supplies in the simulator, I wasn't getting the fidelity of what could be had with a linear solution. I keep track of some of the latest LED drivers and finding a 350 mA-750 mA driver that utilizes PWM dimming at ultrasonic frequencies is near impossible. Unfortunately, I just haven't had *that* much time to devote to creating a PWM driver that operates at 30 kHz max.

    For your reference, some of my design goals are to use components that are readily available to most just by going to their local electronics hobby shop (e.g., Radio Shack, Frys Electronics, and their variants). If I begin to specify obscure and hard to find parts, there are a couple of problems: (1) they are likely going to be surface-mount devices (convenient to reduce the size of a project but difficult for novices to use / difficult to prototype), and (2) they will be expensive.

    The main drawback with a linear only system is the heat dissipation. I may force some of the design issues, such as limiting the output to 1 W devices and hard-specifying the power supply so the wasted power is reduced. Another option is to use a high-efficiency buck (step-down) converter as the front-end to a linear system. This will likely be the best compromise.

    One other option is to utilize a small microcontroller and RGB LED driver "backpack" called a "Rainbowduino" (see rainbowduino.seeedstudio.com). It is an 8x8 RGB matrix that could be interfaced with the Procyon--not as powerful to display on a wall, though, but very fun.

    I have an existing circuit board that uses constant-current DC-DC converters but the PWM frequency is limited to 200 Hz. For anyone interested in this design, I will happily provide you with the circuit board artwork and bill of materials. I have a number of microcontrollers and over the next couple of weeks before my fall semester (my last one!) I will program one with a simple program that will down-convert the ultrasonic PWM frequency from the Procyon unit to the 200 Hz maximum PWM that the Recon converters use. I do not know what the lower PWM frequency will mean in terms of actual entrainment. The expected latency would be one 200 Hz PWM period (i.e., 1/200 s).

    I'll try to get a photo out of the current circuit board working with a Procyon unit via a small microcontroller that converts the signals. The output is a 2" PAR-16 RGB 1W LED light.

    --Scott

  3. #23

    Default Re: Circuit board coming for Procyon interface

    Hi Scott,

    Your idea looks intriguing I was wondering how you are getting on developing the design?

    Mike

  4. #24

    Default Re: Circuit board coming for Procyon interface

    Design coming along great! Have decided to use a pre-regulator (LM2596) followed by a ultra-fast low-dropout linear device (LM1897)--don't quote me on the exact parts--I'm going off the top of my head as to what they are. Now, the heatsink requirements have been mitigated significantly and I don't need to have large smokestacks in order to play with the lights

    This semester is a real drain on my time (robot dynamics, senior capstone design, and a bunch of other stuff), but I'm whittling away at this as time permits and a design will be ready before long...

    Ciao,

    --Scott

  5. Default Re: Circuit board coming for Procyon interface

    Good to hear progress Scott. Looking forward to updates

  6. #26

    Talking Re: Circuit board coming for Procyon interface

    After hours of searching for "just the right" switching pre-regulator, I've given up with saving power and decided to give you all what I've been promising for years (?).

    Please find attached a .zip archive that contains the PCB artwork, as well as the schematic and Gerber files (should someone want to have the boards made at a PCB shop). I have tried to annotate the PCB and schematic as much as possible, and the included bill of materials lists the heatsinks that I was picking from.

    Please note that this circuit board is quite large due to my attempt at handling various user requirements and power supply options. My last portion of the PCB was to include a fuse for each of the channels, but that meant that I had to dig through my packed boxes (moving) to find the fuse holder that I used in order to draw the device on the board. All someone has to do is connect a fuse inline between each R/G/B channel's output and the 1W LED, though, so I decided to get everyone the PCB.

    Fortunately for me, I have finished my electrical engineering degree (yeah!). However, I'm now in the middle of a move to Vancouver Island near Victoria, BC.

    I have a much more complicated version of this that is currently in use, but it doesn't handle the 26 kHz switching frequency like this linear design uses. I will provide additional circuits and PCBs when I get a less power-hungry driver created.

    Again, please know that the goal with this project was to (1) provide a proof-of-concept Procyon interface, and (2) use readily-available parts (read: through-hole or DIP parts) so that most hobbyists could make this PCB.

    For those who cannot download the attached .zip file, I have posted it on my FTP site as well for your convenience. I'd recommend that you download it soon as I don't know if my domain will transfer with me to Canada.

    The URL to my FTP location is: http://ganz.blueelectronlabs.com/procyonIO_linear.zip

    I'm going to flash my Procyon with the latest firmware now to reduce the buzzing noise and go strobe myself into bliss.

    Enjoy with my best wishes,
    --Scott Thompson
    Attached Files Attached Files

  7. #27

    Default Re: Circuit board coming for Procyon interface

    Hi, Electronguy--

    What a great project, and thanks a bunch for posting it here! Looks like it would make a good DIY kit... wonder if Sparkfun would be interested... it would be hard to change the PWM rate, as it's part of the audio interrupt service interrupt & would need to be moved to a separate one. Also, a higher sample rate makes for more accurate construction of the sine, pulse and triangle wave outputs.

    Good luck with your next phase, and if you happen to be in the San Juan islands, do look us up! We can see Vancouver Island from where we are, on Orcas Island.

    -Robert

  8. #28

    Default Re: controlling external LED arrays with Procyon

    Hello,
    Anyone successfully finished this project and can share the experience, please?
    Thank you!
    Ted

  9. #29
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    Default Re: controlling external LED arrays with Procyon

    Quote Originally Posted by ted View Post
    Hello,
    Anyone successfully finished this project and can share the experience, please?
    Thank you!
    Ted
    The info was in another thread, so I merged them to this thread. See above.
    -Andy.

    Hey, if someone makes a good post, don't forget to click at the bottom of their post to add to their reputation!

  10. #30

    Default Re: controlling external LED arrays with Procyon

    Quote Originally Posted by Andy View Post
    The info was in another thread, so I merged them to this thread. See above.
    Thank you for quick response! I saw Scott's DIY project and it's really great but it works with 1W LED only. PandoraStar/Ajna is 10W LEDs I believe and for me personally stronger light worked better than Limina's. The only problem with Pandora - it is very expensive!

    Can this DIY project be recalculated for 10W LED? Is it going to be compatible with Limina / Kashina?
    I am not an "electronics wiz" and would't mind to compensate time.

    I tried to order
    MELs, but unfortunately they wrote they don't make them any more and no information about it not available.

    Do you have any other information how it can be done by any chance?

    I'm not a tech person but have just basic knowledge and idea how it works and was thinking using
    Relay Module with Optocoupler Isolation Support like this one:

    https://www.amazon.com/dp/B07K5D7XNW...ing=UTF8&psc=1

    Any other suggestion or info you have and can share please?

    Thank you!

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