NeoPixel LEDs and a external resonator with a picaxe

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Krafter

Member
I'm interested in making my own stage lighting for our band. I came across NeoPixel LED rings but after further research, it seems as if the PICAXE isn't fast enough by itself. I watched this video and he has the clock speed for his PIC set at 48mhz. My question is, can I use an external resonator and a X2 to accomplish this task? I really don't wont to invest in the equipment and learn a different language when I'm just now getting to know PICAXE programming.

Can I overclock the PICAXE?

All parts have an internal resonator allowing operation up to 32MHz for the M2 parts and up to 16MHz for X2 parts.

The X2 parts can also be used with an optional external resonator allowing up to 64MHz operation.

When the X2 parts are used with an external resonator the operating speed will be four times the resonator frequency; for example, for 64MHz operation, specify setfreq em64 and use a 16MHz resonator.
- See more at: http://www.picaxe.com/FAQs/PICAXE-Microcontrollers/#sthash.yRukAiyX.dpuf
Click to expand...
 
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B

bpowell

Senior Member
I don't think the silicone will handle the overclocking necessary to get 48MHZ raw-pic performance out of a picaxe.

There is too much overhead in the PICAXE as it's already running code, and it's running your user code inside its own code.

That being said, there are examples here of using LED light strips (which the Neo-ring is...) and the Hardware SPI port...but, I think you need to have patterns pre-loaded in memory...you can't do "on the fly" animation I don't believe.
 
K

Krafter

Member
Thank you very much! I will look into the APA102. It seems to be easier to work with compared to the NeoPixel. I just want the ability to control each LED independently.
 
M

mikeyBoo

Senior Member
PCA9685 may workee

hi Krafter,
Sounds like a fun project!
For-what-it's-worth dept.:
Even using a Picaxe-08M2 running at 4MHz with lo-speed I2C, combined with PCA9685 I2C 12-bit 16-Channel PWM controllers from Adafruit,
it is possible to do some extremely elaborate lighting effects. You can use multiple boards if you want to do "Times Square style"
effects. I use one of the PCA9685s for doing chasing & glowing effects in my kayak hull.(User Projects - Miscellaneous: Picaxe
Kayak Control Projects, see the .bas file for PCA9685 code examples). Procedures (subroutines) related to the PCA9685 begin with "LED."
(also see the init: procedure). Of course, if you wanna' save some bucks, get PCA9685 chip & design your own board.
If it seems feasible to you & you know how to make single-sided circuit boards at home, you'd be welcome to my board designs. The 8x power
MOSFET driver boards I designed are for 12/24vdc power control. Wouldn't recommend over 2A per channel (keep in mind 5A per channel @ 100% PWM
= 40A).
Of course, you would have to write the light control routines to suit your taste.
Good luck with your project! (attached .pdf shows stuff we used on yak, may give you some ideas)
 

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B

BESQUEUT

Senior Member
Krafter said:
Thank you very much! I will look into the APA102. It seems to be easier to work with compared to the NeoPixel. I just want the ability to control each LED independently.
Click to expand...
Be aware that each led is 5V 25mA
so 144 LEDs/m is 3.66 A/m
Or 36 A for 10m
I suggest having a power feeding at least each 2,5 meters, or both ends for 5m strips...
 
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