Teensy 3.2 12v Led using mosfet

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Sorry total noob, I’ve managed to get the led’s fading using Arduino uno, when I use the same sketch on my teensy 3.2 is is a very feint fade hardly noticeable at all.
They are just normal red 12v led’s left over from a sign job I’ve managed to use half of them with the Arduino uno without problem.

Can anyone help ?
Thanks in advance
 
Can you post your code that runs fine on Uno? Can you also tell us what LED & FET you used and how you wired it?
Please notice the forum rule on top of this page: Always post complete source code & details to reproduce any issue!

Paul
 
Whatever circuit you're using to drive the LEDs works with the 5V output from an UNO. But a Teensy 3.2 outputs 3.3V which is probably insufficient. As @PaulS asks, post a circuit diagram and the code.

Pete
 
Whatever circuit you're using to drive the LEDs works with the 5V output from an UNO. But a Teensy 3.2 outputs 3.3V which is probably insufficient. As @PaulS asks, post a circuit diagram and the code.

Pete

The teensy isn’t powering the led’s it’s just controlling the gate on the mosfet which in turn is controlling the earth from mosfet to led’s
I’m not even sure how to draw a circuit of it I’ll have a go and I’ll past the code 👍
 
Yeah, I'm pretty sure the FET VGS(th) is the problem. So the part# of that FET will help.

Paul
 
Yeah, I'm pretty sure the FET VGS(th) is the problem. So the part# of that FET will help.

Paul
Paul thank you so much for taking the time and effort to respond....... please don’t be mad when I say I have no idea what you just said means.
 
Maybe your solderless breadboard is different from mine, but your MOSFET is all on the same bus pins. Gate is shorted to drain and source. the RGB pins are each on a different buss.

If your board is configured such that the drain is connected to the LED negative for RGB, is your LED strip intended to be powered with 12 volts? I see a 9V Duracell battery for the 12VDC so I'm suspicious of the wiring image in general.
 
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Saw that too, but I guessed the breadboard has all the rows connected, not the columns as usual.
And it worked for an Uno apparently?
 
The teensy isn’t powering the led’s it’s just controlling the gate on the mosfet

The Arduino Uno was 5V, the Teensy is 3.3V, so its likely your MOSFET won't be turning on properly - most logic-level
MOSFETs require at least 4.5V to fully switch on, so the performance from 3.3V isn't guaranteed.
Also The Uno can put out more current from its pins than a Teensy, speeding up the switching if the MOSFET has a lot
of gate capacitance.
 
I'd put a 1K resistor in series with the gate. As is, damage might be possible.

+1 on using a small logic level mosfet rated for 3.3V VGS.
 
Not all mosfets are created equal. Many of them are meant to be controlled by 10V to 15V signals. Those types tend to work with greatly reduced performance if driven with only 5 volts, but won't work well at all with only 3.3V. And how they work with low gate drive can vary quite a lot with temperature and even between different pieces of the same part. My best guess is you might have one of those mosfets meant for 10-15 volt gate drive.

The diagram linked from msg #6 has multiple problems. Aside from using the breadboard rotated 90 degrees, the circuit has no resistors to limit the current through the LEDs. With a mosfet meant for 10 volt drive, the mosfet might be acting as a resistor of approximately the right amount to prevent damage to the LEDs if driving with only 5V from Arduino Uno, but again, the actual mosfet performance when under-driven can vary quite a lot, so that's not reliable.

Of course, this involves quite a bit of guesswork. We can help you much better if you tell us specific details, like the mosfet part number. Showing photos of how you actually connected the parts & wires is also a good path to getting much more useful help here. Don't be shy. If you look over the many threads on this forum, you'll see we have a pretty excellent history of figuring out what's wrong with breadboard-built circuits when we can actually see photos.
 
Changed the mosfet
Could you still let us know the partnumber of the MOSFET that was initially in your design and the partnumber of the MOSFET that solved the problem? That may help other people as well that run into this issue and search this forum for an answer/solution.

Thanks,
Paul
 
When someone talks about red 12v leds, IMO it's likely that there is some current limiting device included in that description.
 
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