Light sensor Board switch help

Thread Starter

tc61

Joined Feb 11, 2009
9
Hello,

I have one of these boards ( http://arduino-info.wikispaces.com/Brick-LightSensor-Analog-Digital ). I would like to use the output terminal to switch a N type Mofset that will run a small motor. My question is when I use the digital output it turns on and off. On it shows close to the input voltage of the sensor 5v (shows 4.938) but when it goes off it never goes to 0 volts.
When it is low should there be voltage and will this voltage effect the MOFSET being it a 0-5v base. If I use the analog output it never gets low enough to turn off the MOFSET. Any suggestions?

Thank you in advance.
 

BobTPH

Joined Jun 5, 2013
8,967
How close to zero? If it is well below the theshold voltage of the MOSFET you should be okay. Also, make sure you are using a logic level MOSFET, one the is fully on at 5V. Most MOSFETS require more like 10V to turn on completely.

Bob
 

tracecom

Joined Apr 16, 2010
3,944
Hello,

I have one of these boards ( http://arduino-info.wikispaces.com/Brick-LightSensor-Analog-Digital ). I would like to use the output terminal to switch a N type Mofset that will run a small motor. My question is when I use the digital output it turns on and off. On it shows close to the input voltage of the sensor 5v (shows 4.938) but when it goes off it never goes to 0 volts.
When it is low should there be voltage and will this voltage effect the MOFSET being it a 0-5v base. If I use the analog output it never gets low enough to turn off the MOFSET. Any suggestions?

Thank you in advance.
Do you have a pull-down resistor on the gate of the MOSFET?
 
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