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Author Topic: Profezzorn's first build (graflex 2.0, teensy, prop shield, neopixel led string)  (Read 30422 times)

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Offline profezzorn

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Circuit diagram:



Some notes:
  • I'm too lazy to draw parts, so the LEDs and BEC/UBECs look nothing like what they look like in real life.
  • I'm not planning to have any LEDs for a crystal chamber or anything like that. If I did, I would just add them to the same chain of neopixels as the blade. (I might try to stick an LED in/behind the glass eye...)
  • I have three buttons in the diagram (power, aux, aux2) but I'm not sure if my final design will use that many buttons.
  • Obviously the blade will have a lot more LEDs, the chain just continues.
  • The green thing behind the teensy is supposed to be the prop shield.
  • The batteries are actually li-ion, generating a total of 10-15 volts.

« Last Edit: June 02, 2016, 09:28:07 PM by profezzorn »

Offline profezzorn

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Got the LEDs I ordered, plugged one in and tried it.
Annoyingly, it starts up with a blue color, also it flickers a lot when I try to control it.
Not sure if I need a 5v buffer between the teensy and the LED, or if it's because the timing is off.
(The datasheet seems to indicate that the PL9823 expects different timing than a WS2811 led, so I'm going to try different timing first.)

I'm probably going to order some APA106 leds too, just in case.

Offline profezzorn

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First light




Turns out the flickering LED problem I had was just a bad connection.
And yes, I've rubberbanded (verbing weirds language) my electronics to a stick so I can wave it around. :)

Offline profezzorn

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I tried to start building the LED string today, only to discover that the legs on these LEDs are a bit too short to build a traditional LED string. I'm going to find some single-strand wire (to avoid short circuits) to use as a support structure.

Here is what my failed experiments look like:

Offline profezzorn

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Found a suitable 1mm copper wire in some old coax cables. (I have a whole box of them, kindly provided by.... wait for it... my cable provider!) A bit of a pain to get it out, but I think it should work pretty well.

Offline profezzorn

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Proof of concept:



Still to trim the legs and solder the wrapped bits together though.

Offline TheBaconWizard

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So, is the idea that people could use neopixels OR a traditional string?

Offline profezzorn

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Generally speaking, the idea is that people can do whatever they want. Since the teensy has lots of in-out ports, and the source will be available (if anybody wants access to the source sooner rather than later, let me know) any type of setup could be implemented. Driving a regular string blade would require some external components though, like a FET + resistor or a PEX. Same thing if you want to drive a luxeon-style setup with a teensy board.  I'd be happy to draw up some alternate circuit diagrams and hack up some code, but I'd need help testing stuff since I'm not planning to build any of those things myself.  Basically, the number of pre-defined ways to use the code depends on how many people are interested in building something based on this setup.



Offline profezzorn

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Turns out I forgot to add the voltage divider needed to check the battery level, updated circuit diagram:


Offline profezzorn

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I think I'm going to have to find new LEDs. The PL9823 just have too many things wrong with them:
  • They default to blue, (who thought that was a good idea?)
  • They use too much power when idle (I could fix this by adding a FET, but when I turn them back on they will turn blue again!)
  • They are not bright enough. My Black Series Luke Skywalker Force FX is equally bright, in spite of having fewer LEDs per foot.

Offline profezzorn

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Ordered some slim WS2811 strips from ebay. I don't have enough power for the 144 leds/meter strips unfortunately, so I'm going with 60 leds/meter. I'll glue these strips together back-to-back and wrap them in packing foam to diffuse them. I'm still worried that they won't be diffused enough though.

I might still build the PL9823 blade while I wait for the strips to arrive, depends on how bored I get. :)

Offline TheBaconWizard

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Ordered some slim WS2811 strips from ebay. I don't have enough power for the 144 leds/meter strips unfortunately, so I'm going with 60 leds/meter. I'll glue these strips together back-to-back and wrap them in packing foam to diffuse them. I'm still worried that they won't be diffused enough though.

I might still build the PL9823 blade while I wait for the strips to arrive, depends on how bored I get. :)

I'll be super interested in this. I was thinking of using 60/m for a cheap string, maybe 3 strings per blade arranged around some kind of core. I bet they'll be diffused enough.

Offline profezzorn

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Ohhh, I just had a neat idea!

I think I'll add a FET before AND after the 7A bec, and I'll make sure that the one that goes after the BEC is connected to a PWM-capable pin on the teensy. That way I can drive either "normal" LED strings or WS2811-based led strings/strips with with the same hilt electronics. I'll use the blade identifier resistor to switch to the correct control logic.  The standard string blade will need a resistor to drop the voltage down from 5.5 volts though. (Should be something like 1.1 Ohms for 100 leds.) The formula for the resistor would be (5.5 - led forward voltage) / (LED forward current * number of LEDs).

I'm currently thinking that I'll build one PL9823 blade, one based on WS2811 strips, and one traditional one, based on some small blue LEDs. (Although, it seems that ranking LEDs based on total light output is nearly impossible as the standard measurement is mcd, which depends on the spread of light, and every LED has a different light distribution pattern... Wish they would just publish lumens per watt...)

Offline profezzorn

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It's soo pretty!


Offline profezzorn

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I think I'm going to upgrade my battery solution to 4x14500 IMR batteries. IMR batteries generally support higher current than regular LI-ION batteries. I found some that should allow for continuous draws up to 4 amps, which should give me nearly 50 watts of power to play with... :)  (Assuming I don't melt something first...)

« Last Edit: June 09, 2016, 12:39:34 AM by profezzorn »