This project demonstrates how to use a N Channel MOSFET to power on/off a peripheral. The MOSFET, controlled by the ESP32, is used to power-down power hungry devices when they are not needed. For example: a GPS device, a 5V fan, a 12V fan.
This example uses a MOSFET to turn a 5V Pi-FAN fan (on the +5V power rail) and a standard LED (on the +3.3V power rail) on and off using a GPIO pin of the ESP32 microcontroller.
- ESP development board. I suggest to buy a popular development board with good technical documentation and a significant user base. Examples: LOLIN D32, Adafruit HUZZAH32, Espressif ESP32-DevKitC, Pycom WiPy.
- N Channel Power MOSFET that is 3.3V compatible. Good ones:
- IRF3708 N-Channel Power MOSFET in package THT TO-220.
- IRLML6244PBF N Channel MOSFET in package SMD SOT23-3 (can be soldered easily on a SOT23-3 breakout board).
- A 5V 200mA PI-FAN fan.
- A standard LED (red 20mA).
Note: you can omit one of the 2 peripherals (LED / fan) to make it simpler.
- A working installation of the Espressif ESP-IDF V3.2 development framework (detailed instructions @ http://esp-idf.readthedocs.io/en/latest/get-started/index.html).
mkdir ~/esp
cd ~/esp
git clone -b v3.2 --recursive https://github.com/espressif/esp-idf.git esp-idf-v3.2
- A C language editor or the Eclipse IDE CDT (instructions also @ http://esp-idf.readthedocs.io/en/latest/get-started/index.html).
PIN LAYOUT & WIRING
FAN => ESP32 Development Board
-------------- -----------------------
1 Positive 5V/VUSB pin
LED => 1K resistor => ESP32 Development Board
-------------- ----------- -------------
1 Positive passthrough 3.3V pin (not the 5V or VUSB pin!)
MOSFET Destination
---------------- -----------------------
1 GATE ESP32 dev board: GPIO#4 (Adafruit Huzzah32 GPIO#4 = bottomleft-6)
2 DRAIN LED: GND
2 DRAIN FAN: GND
3 SOURCE (GND) ESP32 dev board: GND pin
- Run
make flash monitorto build and upload the example to your board and connect to its serial terminal.
I (0) cpu_start: App cpu up.
...
I (397) mjd: *** DATETIME 19700101002041 Thu Jan 1 00:20:41 1970
I (417) gpio: GPIO[13]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
I (427) myapp: Init POWER MOSFET...
I (427) gpio: GPIO[4]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
I (437) myapp: Wait 5 seconds before turning the Gate ON
I (5447) myapp: POWER MOSFET Gate := *ON (the FAN and the LED should turn on)...
I (5447) myapp: Wait 15 seconds whilst the gate is ON..
I (20447) myapp: POWER MOSFET Gate := *OFF (the FAN and the LED should turn off)...
I (20447) myapp: ***SECTION: DEEP SLEEP***
I (20447) myapp: Entering deep sleep (the MCU should wake up 15 seconds later)...
- Change the logging level of each ESP32 project using
make menuconfigfrom "INFO" to "DEBUG" if you want to get more details about the requests and responses that are exchanged using the UART data channel.
Do you also want to create innovative IoT projects that use the ESP32 chip, or ESP32-based modules, of the popular company Espressif? Well, I did and still do. And I hope you do too.
The objective of this well documented Starter Kit is to accelerate the development of your IoT projects for ESP32 hardware using the ESP-IDF framework from Espressif and get inspired what kind of apps you can build for ESP32 using various hardware modules.