Forgive me this is one of the first things I have ever done with a microcontroller. I am trying to simulate sunrise/sunset with a strip of LEDs much like these http://goo.gl/ehK7Ng. Hooking them up directly to 12v they are very bright. I then wired them through a mosfet (IRF510) like this.
If I jump the gate to positive, the LEDs light up full bright so I know the mosfet works. Once I hoook the gate to a GPIO on my raspberry pi, They never seem to get full bright. I am able to dim them using PWM, but even with the duty cycle at 100%, or they are not full bright. I will admit, and I dont know if this is the reason, that I do not have the 10k resistor between the gpio pin and ground. Any thoughts?
LEDs not full bright through mosfet
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- malichite
- Posts: 5
- Joined: Fri Oct 31, 2014 12:48 am
Re: LEDs not full bright through mosfet
Wanted to add an update. The small strip of LEDs is only for testing. Ultimately I am hoping to be able to run 300ish Watts at 12v worth of lights off of this.
- adafruit_support_bill
- Posts: 88087
- Joined: Sat Feb 07, 2009 10:11 am
Re: LEDs not full bright through mosfet
Sounds like your MOSFET Rds at Arduino signal voltage is too high to efficiently drive that load. From the datasheet, it looks like it wants a control signal closer to 10v.
These are designed to be driven directly from 5v TTL logic: https://www.adafruit.com/products/355
These are designed to be driven directly from 5v TTL logic: https://www.adafruit.com/products/355
Please be positive and constructive with your questions and comments.