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


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.
What about elevensies? Luncheon? Afternoon tea? Dinner? Supper?


ok I will try to do the math myself. Thanks



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).



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?


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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