This hookup guide is not only limited to the MOSFET breakout board, here you can learn basics of MOSFET, so that you can build your own circuit in a breadboard/ Protoboard with components we are providing or use if you have some with you. Check below the contents we covered in this tutorial:

• MOSFET BASICS

• Hardware Needed

• MOSFET Breakout PCB Introduction

• PCB SilkScreen

• Gate Control Circuit Schematics

• Jumper Settings

• PCB Assembly

• Heatsink Assmebly

• References

MOSFET BASICS

Most of you have heard of BJT and MOSFET but still you have doubts regrading MOSFET, here we are covering some basics of MOSFET before going to the breakout board details. MOSFET stands for “metal-oxide semiconductor field-effect transistor”. It is a special type of field-effect transistor (FET). Its gate input is electrically insulated from the main current carrying channel and is therefore also called as an “Insulated Gate Field Effect Transistor” or “IGFET”. Unlike BJT which is ‘current controlled’, the MOSFET is a voltage controlled device. The MOSFET has “gate“, “Drain” and “Source”  terminals instead of a “base”, “collector”, and “emitter” terminals in a bipolar transistor. By applying voltage at the gate, it generates an electrical field to control the current flow through the channel between drain and source, and there is no current flow from the gate into the MOSFET. Unlike the BJT, the FET is a unipolar device since it functions with the conduction of electrons alone for the N-channel type or on holes alone for a P-channel type.

Hope now things are little clear to you now, but this is not enough, so we had covered types of MOSFET as well, refer the types below:

• N-Channel (NMOS) or P-Channel (PMOS)
• Enhancement or Depletion mode

N-Channel – For an N-Channel MOSFET, the source is connected to ground. To turn the MOSFET on, we need to raise the voltage on the gate. To turn it off we need to connect the gate to ground.

P-Channel – The source is connected to the power rail (Vcc). In order to allow current to flow the Gate needs to be pulled to ground. To turn it off the gate needs to be pulled to Vcc.

Depletion Mode – It requires the Gate-Source voltage ( Vgs ) applied to switch the device “OFF”.

Enhancement Mode – The transistor requires a Gate-Source voltage ( Vgs ) applied to switch the device “ON”.

Despite the variety, the most commonly used type is N-channel enhancement mode. There are also “Logic-Level” and “Normal MOSFET”, but the only difference is the Gate-Source potential level required to drive the MOSFET. Refer the symbols in the diagram below to distinguish the types of MOSFET.

MOSFET TYPES

Now consider the following points while connecting the load/Heatsink to the MOSFET:

• Because load  has resistance, which is basically a resistor. For N-channel MOSFET put the load at the Drain side and Source is usually connected to GND. If load is connected at the source side, the Vgs will needs to be higher in order to switch the MOSFET, or there will be insufficient current flow between source and drain than expected
• For P-Channel MOSFET put the load at the source side and drain is usually connected to GND.
• Typically the heat sink on the back of a MOSFET is connected to the Drain! If you mount multiple MOSFETs on a heat sink, they must be electrically isolated from the heat sink! It’s good practice to isolate regardless in case the heat sink is bolted to a grounding frame.

Hardware Needed:

MOSFET Breakout Board	N Channel MOSFET (IRF1404)	Heatsink -Multiwatt Package
1KΩ Resistor	Screw Terminal- 2pin (5mm)	Male Header 40 x 1

MOSFET Breakout PCB Introduction:

This basic is enough for now, to getting started with MOSFET. There are many more things which you can do with MOSFET, we did not covered all the things in details here, but we will recommend you to start using MOSFET in most of the circuits to understand its uses in various applications, only practice makes man perfect, so this is what we are expecting from you that you will build something really cool projects using MOSFET. Now its time to go in details of MOSFET breakout board. Refer the board shown in the Image below:

MOSFET BREAKOUT PCB

PCB SilkScreen:

Now if you notice, then you can see the silkscreen at the bottom and the top will distinguish between P Channel side and N channel Side. You only need to solder the parts which are dedicated for that specific channel, i.e if you are willing to use just N channel Enhancement type MOSFET in your project, then all you need to do is to solder the parts needed only for N channel, which you can easily distinguish by referring the silkscreen. We had highlighted the TOP side silkscreen in the following image to distinguish between the two channel side.

N Channel / P Channel

You can refer the following image to see which resistors refer to which channel, this you can easily distinguish, if you refer the bottom silkscreen.

N Channel/ P Channel Resistors

Gate Control Circuit Schematics:

We had added the Pull_Up / Pull_Down Resistor for the Gate, this feature is disabled by default, but if you need you can use this feature in your circuit by enabling the jumper J1/J2. Refer the below Schematics for better idea of the circuit.

Gate Circuit Schematics

You can see in the following images we had highlighted the pull_up/ pull_down resistors.

Gate Control Resistors

Jumper Settings:

These Pull-Up/Down Resistors (R_U/D) is disabled by default and can be enabled by adding solder to the Jumper Pads J1 for P-Channel and Jumper Pads J2 for N-Channel, the Vcc and Ground side is indicated in the Silkscreen. Its a 2-Way Jumper thus center pad is the main path and you need to apply solder either to “+” or “-“, so make sure to solder only required logic for each jumper, i.e either Vcc or ground. In case you need to disable this feature from the circuit, just remove the solder from the pads you applied. You can see the J1 and J2 Jumper in the following image and the + and – indication against its pad.

Jumper Pads

Note: Do not Solder all the three pads of the jumper together, this will create a short between Vcc and GND.

Refer the below table for jumper selection chart:

You can ignore these R_U/D and R1_U/D resistor in the breakout board, if you don’t need pull_up/Down Feature. Now if you notice the Gate schematics you can see that the control signal is passed via Gate Resistor, so you need to solder this in your breakout PCB to get the circuit working, if you don’t want any Gate resistors, you can solder the 0Ω Resistor in the R_G / R1_G. We had Provided some standard values of resistors with this breakout board, so you don’t need to worry much about it, all you need to do is, to solder the resistors as per your requirement. Refer the below image for the Gate resistors slot in the Breakout board.

Gate current limit

Note: MOSFET will not work if R_G / R1_G  Gate Resistor is left open, atleast you must solder 0Ω Resistor or short the slot with solder/Wire.

PCB Assembly:

The Drain and  Source pins are indicated clearly on the TOP/BOTTOM Silkscreen, this can be accessed either with screw terminal or with male/female Headers, you can solder whichever you need. You need to solder three pin header for Gate, Gnd, Vcc pins as well, so as to control the MOSFET from microcontroller or any other circuit. Make sure to use the Gate Control header of the same channel as that of MOSFET. Refer the legend and the diagram below for the  N- Channel MOSFET assembly:

Legend

N Channel MOSFET Assembly

Heatsink Assmebly:

The board supports one N Channel and one P-Channel MOSFET at the same time, since both channels have its own sets of resistors, headers and screw terminal slot, make sure that all the things are properly connected. For the high current application your MOSFET will heat up like crazy, thus you need to add heatsink to provide cooling to the MOSFET, we had provided Heatsink Slot to be soldered on board for both type of MOSFET, refer the following image on how to use heatsink with MOSFET:

Heatsink Multiwatt

N Channel MOSFET with Heatsink

The P Channel also supports Heatsink. If you are using Heatsink with N Channel  MOSFET then it is not possible to use P Channel MOSFET or vice versa. The Heatsink is not provided with the MOSFET Breakout PCB, you need to buy it separately if needed. If you are facing any issue or difficulty with the PCB, do let us know, our team will help you with all the issue, we are happy to hear from you, do let us know your feedback.

References:

• MOSFET types Image Source:  Electronics Tutorials
• Heatsink Image Source: Sparkfun

Now a days we have seen lots of devices are available in the market which can be controlled over the internet either using web browser or using mobile application. This project is all about controlling the Power socket over internet using web browser. We had used ESP8266 Thing in this Project, since it will give you the flexibility to make a flexible product with internet connectivity using the wifi. Particle photon is another option to be used in this project and it will give great advantage over ESP8266 Thing that, you can flash the code over the internet without bothering about where the product is. Now we will show you how to build your own eSocket.

• Parts Needed
• ESP8266 Thing 
• Circuit Integration
• Source Code

Parts Needed

• ESP8266 Thing
• FTDI Basic USB to Serial Converter
• Relay
• ULN2803
• Power Supply 5v
• Power Supply 12v

ESP8266 Thing

The ESP8266 is a low-cost Wi-Fi chip with full TCP/IP stack and Microcontroller capability produced by Shanghai-based Chinese manufacturer, Espressif. There are many third party modules With ESP8266 available in the market and you can decide which one suits best for your application, we are using the Sprakfun ESP8266 Thing in this tutorial.

The SparkFun ESP8266 Thing is a breakout and development board for the ESP8266 WiFi SoC – a leading platform for Internet of Things (IoT) or WiFi-related projects. These are some features of the board:

ESP8266 Thing Features:

• All module pins broken out
• On-board LiPo charger/power supply
• 802.11 b/g/n
• Wi-Fi Direct (P2P), soft-AP
• Integrated TCP/IP protocol stack
• Integrated TR switch, balun, LNA, power amplifier and matching network
• Integrated PLLs, regulators, DCXO and power management units
• Integrated low power 32-bit CPU could be used as application processor
• +19.5dBm output power in 802.11b mode
• Arduino IDE integration
• Breadboard Compatible Breakout Headers position
• Power On-Off Switch
• Status LED
• Operating Voltage: 3.3v

Refer the Graphical Datasheet for hardware description

Programming the Thing:

The ESP8266 has a built-in serial bootloader, which allows for easy programming and re-programming. You don’t need a specialized, expensive programmer – just a simple, USB-to-Serial converter.

We use a 3.3V FTDI Basic to program the Thing, but other serial converters with 3.3V I/O levels should work. The converter does need a DTR line in addition to the RX and TX pins.The FTDI Basic’s 6-pin header matches up exactly to the Thing’s 6-pin serial port header. To set up for programming, simply connect the FTDI directly to this port – take care to match up the DTR and GND pins!

Note: While programming the Thing, it’s best to power it off USB. We’ve noticed programming is more likely to fail if the Thing is only powered via the battery.

Going further we need to interface relay with ESP8266 Thing, since we need to control the power socket, the relay we used in this project is of Industrial grade 10A, 250vAC rated and Coil Supply with 12v DC control voltage, you can use any other relay as per your convenience. Our ESP8266 Thing runs on 3.3v control logic, thus we are not able to straight away control the relay from ESP8266 IO Pins, we used ULN2803 Darlington array IC as relay driver, this IC is easily available in the market and can be used to control 8 relays at a time, since we need to interface just one relay to control the socket, we used only one channel of the IC.

Relay

Specifications:

• DPDT
• Mini Middle Electromagnetic Relay
• 8Pins 2NO+2NC
• Current:10A
• contacts:silver plated gold
• LED color:green
• Terminal form:socket type
• LED voltage: AC220/240V
• 12V DC voltage Controlled
• Secondary Side: 10A/240vAC, 10A/28vDC

The relay base module is separate part and needs to be purchased separately, its is rated for 15A, 250v AC, all the pin marking are made on the base itself thus connection is really simple, just refer the schematic shown on the relay body itself.

ULN2803

The ULN2803A device is a high-voltage, high-curren Darlington transistor array. The device consists of eight NPN Darlington pairs that feature high-voltage outputs with common-cathode clamp diodes for switching inductive loads. The collector-current rating of each Darlington pair is 500 mA. The Darlington pairs may be connected in parallel for higher current Types of Logic capability.

Features:

• 500-mA-Rated Collector Current (Single Output).
• High-Voltage Outputs: 50 V
• Output Clamp Diodes
• Inputs Compatible with Various types of Logic
• Relay-Driver Applications
• Compatible with ULN2800A Series

Simplified Schematics:

Pin Diagram:

Connections with ULN2803 are really simple, the channel mentioned with 1B , 2B, …, 8B all are inputs and you can pass on your logic control voltage from microcontroller to these pins, its 3.3v/5v Compatible. The corresponding inverted out will be present on the other side i.e 1C,2C,…,8C.

Connect the GND pin with GND from power supply and COM pin with 12v Supply Input, When a logic one is fed to 1B , you are able to get the ground from 1C, we used the channel 8, thus we connected 8B with ESP8266 pin 12 and and 8C to relay coil ground Pin, we already provided relay coil +ve pin with 12v supply. Refer the schematics in the next section to get a clear idea of the circuit connection.

Click here to See the Datasheet.

Circuit Integration

The complete circuit integration won’t take much time, you can use  breadboard  to integrate the circuit to save your time, we used the protoboards to make breakout boards for the ULN2803 IC and ESP8266 Thing. we used fritzing to make breadboard design for you, just refer the circuit diagram to build your own circuit.

The 12v and 5v power supply is something you can get from adapter around you, power socket or power extension box is something you need to buy. you must buy a big box to fit in maximum circuit Inside it, Precaution must be taken when you assemble this high power circuits.

Schematics:

If you check the above image, you won’t find 5v power supply, its because we fitted it in inside the power socket, the two green wires coming out of the power socket is 5v and GND. The rest you are able to figure out just by referring the schematic shown. We had added working video of the prototype to show you how the things work, use the source code we provided to build your own device.

Source Code

//ON Device                        Control command:   http://192.168.1.167/led?params=1                
//OFF Device                      Control command:   http://192.168.1.167/led?params=2            

#include <ESP8266WiFi.h>
#include <aREST.h>

#define PIN1 13
#define PIN2 12

aREST rest = aREST();

// WiFi parameters
const char* ssid = “xxxx”;
const char* password = “xxxxxxxx”;

// The port to listen for incoming TCP connections
#define LISTEN_PORT 80

// Create an instance of the server
WiFiServer server(LISTEN_PORT);

// Declare functions to be exposed to the API
int ledControl(String command);
void setup(void){
Serial.begin(57600);
pinMode(PIN1,OUTPUT);
pinMode(PIN2,OUTPUT);

// Function to be exposed
rest.function(“led”,ledControl);

// Give name and ID to device
rest.set_id(“1”);
rest.set_name(“esp8266”);

// Connect to WiFi
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
}

// Start the server
server.begin();
Serial.println(WiFi.localIP());
}
void loop() {
// Handle REST calls
WiFiClient client = server.available();
if (!client) {
return;
}

while(!client.available()){
delay(1);
}
rest.handle(client);
}
int ledControl(String command) {
int state = command.toInt();

if(state==1){
digitalWrite( PIN1, 1);
digitalWrite( PIN2, 1);
}

else
if(state==2){
digitalWrite( PIN1, 0);
digitalWrite( PIN2, 0);
}

return 1;
}

Make sure that you had replaced the Wifi SSID and password credentials in the code with your own network one.

Once you upload the code to you device, you are able to get your local IP address from the serial terminal, open the arduino serial terminal at 57600 baud rate, when you are able to see the IP address just copy it and open your browser either from computer or mobile, whichever connected to same network, use the following two commands in the address bar to control the socket:

//ON Device                        Control command:   http://192.168.1.167/led?params=1                
//OFF Device                      Control command:   http://192.168.1.167/led?params=2      

Replace the IP address with you own IP address in the command shown above. Whenever a successful communication is established between ESP8266 and Web, you will get response from the ESP8266 at web end, you are able to see this in the video we added.

We had used the arest in this project, which made our task looks simple, using the arest command line we are able to pass on multiple parameters(all at once) to ESP8266 as string or vise versa.

Download the arest library to run the above code. you need to unzip and copy the library to the arduino library folder.

If you are a web developer the things will be more easier for you, just use the mentioned commands in your web page to link it to the web User Interface. In the next part we will come with more advanced options for the same project so that things will be more easier for you.

Source:

ESP8266 Thing
Frtizing