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Author Topic: MOSFET Shield Modification for PWM Output  (Read 4666 times)

drhassenphefer

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MOSFET Shield Modification for PWM Output
« on: June 13, 2013, 10:56:32 pm »
I'm having trouble figuring out what I have to do to modify the MOSFET shield for PWM. The wiki says this about cutting the solder jumpers:

Quote
The MOSFET can also be connected to P2 by cutting the thin trace between the solder jumper closest to P5 and bridging the solder jumper closest to P0 with solder. The MOSFET can also be connected to P4 by cutting the thin trace between the solder jumper closest to P5 and bridging the middle solder jumper with solder.

PWM can only be used when the device is connected to P4, though softPWM as used in some of the RGB examples may be possible on the other pins.

Specifically, I need a PWM output and I don't know which solder jumper I should be connecting to. Can someone clarify this for me? Or if anyone has a picture of what it should look like after it's modified, that'd be even better.
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digistump

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Re: MOSFET Shield Modification for PWM Output
« Reply #1 on: June 14, 2013, 12:37:05 pm »
Excuse the messy writing - but this should help - this is looking at the board form the top.
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ephphatha

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Re: MOSFET Shield Modification for PWM Output
« Reply #2 on: June 15, 2013, 08:30:20 am »
Except you want to bridge the two middle pads in that image to connect pin 4.
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digistump

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Re: MOSFET Shield Modification for PWM Output
« Reply #3 on: June 15, 2013, 12:23:06 pm »
Yes - sorry that diagram would be to connect to pin 2 - cut the same trace, connected the bottom one instead of the middle one
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drhassenphefer

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Re: MOSFET Shield Modification for PWM Output
« Reply #4 on: June 15, 2013, 09:26:59 pm »
Yeah, I saw that, but I also saw where it needed to be connected in the middle. The paragraph on the wiki made sense once I saw the schematic.
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drhassenphefer

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Re: MOSFET Shield Modification for PWM Output
« Reply #5 on: June 16, 2013, 11:54:38 am »
This is a LED strip light project I'm working on. They're single color, so I don't need a lot of control. Just PWM. I've got it wired up, but now I'm having issues keeping the Digispark on. I'm using a 12V/2A power supply for the lights, and I had hoped to use it to power the Digispark. I got a Buck converter hoping to bring it down to a level the Digispark could use, but it turned out to be underrated.

Now I'm wondering how to use a separate power supply for just driving the MOSFET to power the lights. Would I just run the power supply like the picture attached? Or would I just connect V+ to the lights and the GND connection on the lights to the VOUT on the MOSFET shield?
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digistump

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Re: MOSFET Shield Modification for PWM Output
« Reply #6 on: June 17, 2013, 03:58:56 pm »
Either way would work - but you need to connect the GND of the power supply to the GND on the mosfet shield (so there is a common ground) as well
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