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Topic: Power LED shield (Read 10 times) previous topic - next topic

koyaanisqatsi

I can help you with that, but I'll need some more information:

o A schematic on how you intend to connect the LEDs to the BuckPucks.  I specifically need to know whether they are being connected in series, parallel or a combination. (or let me know if you need me to tell you how to connect them)
o The voltage drop and current rating of each LED.  Better yet, post a link to the data sheet for your LEDs

Also, have you studied the data sheet on the BuckPucks?  They have a few good examples on how to hook up some common LEDs.
http://www.leddynamics.com/LuxDrive/drivers.php
What about elevensies? Luncheon? Afternoon tea? Dinner? Supper?

strus_fr

Hi,
ok I will try to do the math myself. Thanks

LGM-model

koyaanisqatsi

Re the digital signal, your post #43.  Yes I agree with your description of the how the power puck works.  And I agree, your solution within the code  is the most elegant.  

However,  I was referring actually to the schematic use of the M74HC125 Quad Bus Buffer.  The way I read the schematic, it does not invert the input.   I built this up with the digital signal on pin 1 (1G) , +5 v on pin 2 (1A) and the on to the optoisolator on pin 3 (1y).

Charles  

koyaanisqatsi

Ah!  I see what you're doing - drive the !OutputEnable pin and hold the Input pin high in order to invert the PWM signal going to the puck.  I never realized it could be done like that.

I like that!  I was also recently thinking of changing out the 74-125 for an inverting buffer.   Your solution does it without changing the part, but if there exists an inverting buffer with the same pin-out, I'll just change it out for that.  Otherwise I'll update the schematic as above.

Having to keep track of the inverted PWM value in code can be a pain, especially when you're not using the entire range of PWM or having to map it against some other range of values.  For a while I didn't really care.  But as I ran into more problems with it, it started to really annoy me.

Thanks again for your help!
What about elevensies? Luncheon? Afternoon tea? Dinner? Supper?

LGM-model

Here are some pictures of my prototype board made from your schematic and the fiber optic Illuminator.





I think you saved me from blowing up my first Arduino!  Great to collaborate via the forum.  For others, the design works and it is a PITA to make your own board!  I look forward to seeing the kit or PCB soon.  Thanks to all.   Charles  - lgm3d.com

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