Issues with LEDs and ADAFRUIT 16-CHANNEL 12-BIT PWM Driver

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C_Core
 
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Joined: Thu Aug 07, 2014 3:43 pm

Issues with LEDs and ADAFRUIT 16-CHANNEL 12-BIT PWM Driver

Post by C_Core »

Hi all,

I'm trying to drive a couple of bright white LEDs with the ADAFRUIT 16-CHANNEL 12-BIT PWM driver and a raspberry pi. Everything works fine if I connect the LEDs to ground and PWM pins. I don't them to full brightness but that's fine. Connecting many of them will kill the chip and/or my pi so I wanted to use the external power supply. I'm using the 5V lines of an old PSU for that which should give me a lot of power (42A says the sticker on it). So I'm now connecting the LEDs to V+ and PWM as ground. Works as long there is only one. Once I connect another one they both get dimmer. So I guess there is something wrong? As I said this doesn't happen when using VCC as power supply. Does anyone have an idea what's going on?

Thanks in advance,
Clemens

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Franklin97355
 
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Re: Issues with LEDs and ADAFRUIT 16-CHANNEL 12-BIT PWM Driv

Post by Franklin97355 »

Are you running a ground between the power supply and the board and the pi? Could you post clear pictures of your board and the connections to it?

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C_Core
 
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Re: Issues with LEDs and ADAFRUIT 16-CHANNEL 12-BIT PWM Driv

Post by C_Core »

I tried it with common ground and without it doesn't make a difference.
Here is a picture of my setup: https://www.dropbox.com/sc/aiur5zqn87ez ... B1S-jq9XYa

For completeness here is the code I'm using:

Code: Select all

from Adafruit_PWM_Servo_Driver import PWM

pwm = PWM(0x40, debug=True)
pwm.setPWMFreq(200)

for x in range(0, 16):
  pwm.setPWM(x, 4095, 0)

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