Power Mosfet cut out peripheral devices

Question

I have a microcontroller Atmega328p and some sensors like Dht22,Lm35,Soil Moisture,switching voltage regulator and a 9V battery.When my microcontroller is on sleep the total circuit consumption is about 6mA.That i want to do is not only the microcontroller to be on sleep mode but also the rest circuit such as my sensors(except Zigbee).So i used a mosfet as said at the comments below.I created a schema and as you see i connected Gate to pin14(so i will enable through microcontroller the mosfet),Drain to the 5v Switch Mode Regulator output and Source to the Gnd and to the Vcc of each sensor.Now when my device is on sleep my total consumption is about 2mA.Because i don't have someone to verify my schema and i am a newbie i want to check if my schema its ok and so my measurements.Thanks in advance!

ps. Gate Threshold Voltage is about 2-4V.So i have to put a resistor from Atmega pin14 to Gate?

Answer 1

Your current schematic will not work, you have the FET drain connected to VDD and the FET source connected directly to ground. In this use case, the FET acts like a switch when it is "on", so you will just be shorting your 5V rail to ground (sort of, it would probably stick somewhere between 5V and GND until something smoked).

What you want to do is something like this:

^{simulate this circuit – Schematic created using CircuitLab}

The NFET will turn on like a switch when the gate voltage is sufficiently high enough. When it is on, current will be able to flow through the sensors, thus powering them.