One of these circuits will be required for each GPIO pin to relay input that you are connecting. I connected the 5v output to the VCC pin, the ground to ground and a GPIO pin to the IN pin on the relay. This tutorial can be used for both the 4 Channel Standard Relay HAT and the 2 Channel Pi Zero Relay HAT. Yep. Relay - Plug the positive lead from pin 7 to IN1 on the Relay Board. document.getElementById("comment").setAttribute( "id", "aab0a3f7e2e3ddfb931d683b29a8519e" );document.getElementById("bbe67bcb16").setAttribute( "id", "comment" ); Notify me of follow-up comments by email. I am using Python and have used GPIO 17 (pin 11). Raspberry Pi (any Pi should work, I recommend usingRaspberry Pi 3) – read Best Raspberry Pi Starter Kits 2. There are relays who work on +5v coil voltage also, but they need about 30-50mA current which any microcontroller cannot provide. The folks at Seeed Studio provide a rudimentary Python library for the board, but I wanted more. If you have any thought’s about this article, improvements or errors let me know in the comments below and if you found this helpful, why not share it with others. If power is applied to the barrel connector, no other power supply is needed for the Raspberry Pi. But like many other peripherals on the Raspberry Pi Bluetooth also is disabled by default. I have read and agree to the terms & conditions. Next, create a new python file, and let's begin: import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) I connected the 5v output to the VCC pin, the ground to ground and a GPIO pin to the IN pin on the relay. This basic mechanism can be used in your own projects … window.mc4wp.listeners.push( You probably already have it, but just to make sure. When this jumper is connected, the relay can be controlled by the Raspberry Pi. And the pump works but my question is can the 5v relay handle this or should I get a 12v relay. Most relay’s work on 12v or 24v and raspberry pi can’t generate that voltage. All together: In your Pi's terminal, do: $ sudo apt-get install python-rpi.gpio. I have the software more or less working and I am now working on the hardware part. SPI? Four relays with N.O. The PN2222 should be fine as it is a similar transistor but is designed to handle much higher currents. When the Raspberry Pi outputs Low Level from its IO, the LED related to the corresponding channel lights up. It is recommended to set a small resistor between the Pi and the relay, but it is not absolutely necessary with 3V3. Thanks for the great explanation. I used to use, directly, a GPIO on the Pi Zero to do this but after some problems, I was looking at using a relay to close the “RUN to Ground” circuit; operating the relais by setting the GPIO pin from LOW to HIGH for a second and then back to LOW. Ask Question Asked 2 years, 5 months ago. A relay generally has 3 connection points on the controlled circuit side, Normally Open (NO), Normally. You need to put in a transistor and resistors in each connection. Relay module. VCC 5v. You can also power the relays from a separate supply to protect the Pi’s power supply. Jumper wires You can use the preceding links or go directly to MakerAdvisor.com/toolsto find all the parts for your projects at the best price! From my reasearch you shouldn’t draw more than 16 mA from an individual GPIO or more than 50 mA from the GPIO as a whole, but this dates back to the original Pi, for more info have a look at this. When the GPIO pin is activated a voltage is applied to the Base (B) pin of the transistor, this effectively “closes the switch” and allows current to flow between the Collector (C) pin, to the Emitter (E) pin, completing the circuit from the 5 volt Vcc connection on the relay board to Ground. I am coming up with my own pool control system. A nice feature of Python is that, being an interpreter, you can type in and try commands interactively without needing to create a program. Your email address will not be published. Comes with development resources, including examples in wiringPi, WebioPi, shell, python, and bcm2835; What's on the RPi Relay Board. One of the relays powers up my old Win XP driven Compaq which still will let me run 16 bit PowerBASIC compiled programs I wrote many years ago to work with my Weather Station. While it’s easy to trigger GPIO ports, they can only emit 5V. Since I have a PiFace Digital that gives me switchable 5V on the Raspberry Pi, I took this. Ask Question Asked 2 years, 5 months ago. To ensure that it is working correctly when one of the relays is activated so that the led is on, use a multimeter to check that the output of the relay is active, shut down your Pi and the circuit should open. eval(ez_write_tag([[300,250],'tutorials_raspberrypi_com-box-3','ezslot_5',110,'0','0']));In this tutorial, I will show how to control a relay with the Raspberry Pi and what has to be considered. I will not be connecting AC powered equipment to the output of the relay yet but we will be able to see that we have control by the led indicator lights on the circuit board itself. Viewed 2k times 0. Standard Raspberry Pi 40PIN GPIO extension header, Supports Raspberry Pi A+/B+/2B/3B/3B+/4B and … On the Raspberry Pi the control circuit will be operated by our GPIO pins. Joined Dec 1, 2020 9. If you're … For this purpose, relays can be used on the Raspberry Pi: The relay “switch” is utilized by means of a low-voltage pulse. Stackable to 8 layers, the card can add up to 64 relays to each Raspberry Pi in a compact form factor. (remove if you are using an external 5V power supply for the relay board). Ethernet cable or WiFi dongle 5. The relay boards are powered by 5v and the relays are triggered by taking the input pin to ground. i successfully connected but i really need a simple code to run it to trun on and off the Python Flask Story. I’ve had this doubt since I bought those relay boards. The relay board that I am using is “ACTIVE LOW” which means that the relays are switched on when the inputs have a Ground (0 volts) connection applied to them while there are 5 volts connected to the Vcc pin. To avoid wasting too many GPIOs on the Pi it pays off to purchase a GPIO port expander with more than 4 channels. eval(ez_write_tag([[300,250],'tutorials_raspberrypi_com-medrectangle-4','ezslot_11',104,'0','0'])); Either center-left or center-right is connected/”opened”. You can fry your Pi hooking your GPIO directly to your relays… The Raspberry Pi is an amazing single board computer (SBC) capable of running Linux and a whole host of applications. Smart phone with app (described later in the post). While there is no visible output from the program the led’s and relays should cycle on and off every 5 seconds until ctrl-c is entered to break the loop. import time import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(17, GPIO.OUT) GPIO.output(17, GPIO.LOW) time.sleep(0.25) GPIO.output(17, GPIO.HIGH) GPIO.cleanup() To run the script, simply copy the code above to a file on your Raspberry Pi called test-relay.py (or whatever you want). The relay coils are also powered from the 5V. Read it now HackSpace issue 38. Since the Raspberry Pi's GPIO pins output 3.3v I used a set of transistors to take the relay pins to ground. To connect the relay module to your Pi you will need to make the following connections, I’ll be using GPIO pins 22-25 to cover 4 relays but you can use any spare pins. Its isolated optically. The RPi 3 is only capable of supplying about 300mA safely from it’s +5v GPIO Vcc pin. You can drive the proper relay directly, but you need a snubber circuit to stop the inductive kickback caused by removing energy to the relay. Does anyone have any idea what I’ve done wrong please? Raspberry Pi. Python is a versatile and relatively easy to learn programming language. If the GPIO interface of the Raspberry Pi is sufficient, you can also switch an LED when it gets dark. Am completely new to Raspberry Pi, Python and decided to dive in! Step 1 : Controlling switches with Python. Resistors – 2.2kΩ, 10kΩ 7. A bulb. I assume no liability for damages! So if you want the relay to open at a HIGH level, you need to connect the middle and left pins to the circuit. 4 Channel Relay Module 5. Once you have that, you're ready to code with GPIO. The Raspberry Pi Relay Board gives your Pi the ability to control high voltage/high current devices, easily making normal home appliances become intelligent. People have been playing with off-the-shelf relays on Raspberry Pi boards ever since it was released in 2012, and over the years, some companies have maybe Raspberry Pi-specific relay boards such as Strawberry4Pi and Pi-OT.. Two years ago, Sequent Microsystems introduced a stackable 8-Relay board enabling up to 64 relays to be connected to a single Raspberry Pi board. { If you’re looking for everything you need to know about programming python on the Raspberry Pi, you can refer to my previous tutorial on it! With the relay module still connected, you can test out the web relay by first changing directory using: $ cd /home/pi/Rasp2/ch07_web_relay and then either running web_relay.py or web_relay_inverted.py depending on your relay module. When I’m away I need a Pi Zero to do the “shorting” for me. The relay control boards almost all have a schottky diode placed in reverse and parallel to the relay to act as a flyback protection circuit. A relay generally has 3 connection points on the controlled circuit side, Normally Open (NO), Normally Closed (NC) and a … The relay coils are also powered from the 5V. I then start a program I wrote in Return To BASIC to control 16 Relays. Loving with website by the way! In this tutorial we are going to go over soldering the header to the Relay HAT, use Python with the included Pi.GPIO library to write code that triggers each relay, and go over the external relay connections and configuration options on the board. Our first program is going to act like a door with a password. Raspberry Pi Bluetooth: The Raspberry Pi has a built in Bluetooth which makes it very handy and easy to use in our wireless applications. Your description of the resistor configuration seems correct as well. If I’m at home I can simply short “RUN” to an earth and away things go again. I am trying to use a control relay to operate for a certain duration of time. A transistor, some resistors and a diode are all you'll need. As I understand, the base (pin2) of the transistor should connect to a 2k resistor (I do not have a 2.2k on hand), the other side of that resistor should connect to both 10k resistor and to the gpio pin. i successfully connected but i really need a simple code to run it to trun on and off the The 4-RELAY card needs 5V to operate and can be powered from Raspberry Pi or from it’s own 2.1mm barrel connector. gpio python raspberry pi relay; Search Forums; New Posts; W. Thread Starter. Raspberry Pi (2, 3 or 4) 2. The card draws 10mA with all relays off. SD Card (minimum size 8Gb and class 10) 3. gpio python raspberry pi relay; Search Forums; New Posts; W. Thread Starter. All the terminals are low active. The "Pi" in Raspberry Pi standards for "Python Interpreter," reflecting the fact that this is the recommended language on the platform. The relay board shown in the photo above is the same as the one I have here on my bench, (about £5 from Amazon.co.uk) has an Opto isolator on each input to protect the GPIOs and a diode across each relay to protect the driver transistors on the board. When it comes to electronic circuits I am still learning myself so I would encourage you to search for a more detailed explanation. Are there any earth continuity issues? You can use C++ (wiringPi) or Python for it. If you connect all 3 pins, you can use the relay as a kind of switch, leaving it free on the left or right has the effect of an on/off switch. It should be noted that each relay draws approx 72mA from the Pi when activated, given that the Pi itself required 500mA it is important to make sure that your power supply for the Pi can provide this current, a minimum of a 1.5 amp supply should be used to allow for a margin of safety. Standardized shield form factor enables smoothly connection with the Raspberry Pi . Isn’t that enought to protect the GPIOs? Read it now HackSpace issue 38. This might even be enough for a night light, I have to test it. IN1 Control PIN for relay channel 1 - PIN 16 - BCM23 . However – I wanted to use a breadboard with its own 3.3/5v power supply to test multiple relays switching multiple circuits. Hi Required fields are marked *. Being an interpreter there is no need to explicitly compile programs. On the Raspberry Pi's pins: Now you can turn your Raspberry Pi on, and we'll begin the code. And then run the script using: ... perhaps I should have provided more information. When the Raspberry Pi outputs Low Level from its IO, the LED related to the corresponding channel lights up. Thank you for the instructions. The project uses Aleaxa to command the raspberry pi to "turn on" the gate, This makes PIN 7 go high and switch on a relay, the relay then activates the open sequence of the gates. Validating the Raspberry Pi Sees the Relay Board ... Typing allon or alloff will turn all relays on or off. Viewed 2k times 0. I'm new to Raspberry Pi and are working on a Pi3 program that will switch on and off an irrigation pump though a 1 channel relay. Also, if you do use the Pi’s 5v as Vcc to the relay board, you probably shouldn’t put the Pi in a situation where the relay board may be “turning on” more than, say, 5 relays at once. I really didn’t know if that was true or how to do it. Female – Female jumper cable 3. an external circuit (e.g., batteries) and an application (eg, motors) The relays are available as 2, 4, 8 and even 16 modules, depending on what you need. I would like to know, in which applications have you found the use for the Raspberry Pi relays? It then toggles the four relays in sequence for a number of iterations. I connected a 5v relay to raspberry-pi 3b+, 12v peristaltic pump and 12v Li-ion battery. Since the GPIO pins on the Pi output 3.3V when active we need a way to effectively short the input pins on the relay board to Ground when we activate the GPIO pin, the Transistor (2N3904)/Resistor (2.2kΩ, 10kΩ) circuit shown below will achieve this. Part of such home automation projects is to control an electrical load like a light bulb or a ceiling fan. Each relay needs about 80 mA to turn on. The first step is to connect a ground pin on the raspberry pi to the GND pin on the relay. In this tutorial I will be using the following materials: When describing the physical pin connections I will be following the GPIO pin numbering convention shown below. Python Flask Story. Even the relays i’ve bought that are activated via transistor are fine because theyre just switching a transistor off n on to manage a higher current DC. Loosely you can think of the transistor as a switch, when the GPIO pin on the Pi goes HIGH (3.3V) on the Base(B) of the transistor this closes the switch and allows current to flow between the Collector(C) and the Emitter(E) and effectively connects the relay pin to ground(0V), activating the relay. Wilmer Kluever. Now, open up a Python script from the desktop. Dec 11, 2020 #1 I bought a relay like this today for my raspberry pi, and I am encountering a very strange issue. UART? Finally, connect any of the GPIO pins on the raspberry pi and connect it to any of the IN1 - IN4 pins on the relay depending on which relay is used. You use a diode and a small capacitor for that. forms: { If you don't already have a terminal window open, open one then navigate to the folder where you extracted the project files (if you followed these instructions, it should be at home/pi/raspberry-pi-relay-timer. we have this thermal camera that aims to switch off the lights when no one is around and switches on when there is a person detected. Micro SD Card 3. However, if you have two separate circuits this can not happen. ); As I read your post I found myself thinking what can you use the relay board for, what projects can you incorporate a relay board in and what can a relay board make a Raspberry Pi do? Relay control with Raspberry Pi and Python3. Learn coding and computing with the latest all-in-one computer. This will ensure that the transistor circuit is working correctly and in the event that your Pi loses power, whatever you are powering from the relay will also turn off. People have been playing with off-the-shelf relays on Raspberry Pi boards ever since it was released in 2012, and over the years, some companies have maybe Raspberry Pi-specific relay boards such as Strawberry4Pi and Pi-OT.. Two years ago, Sequent Microsystems introduced a stackable 8-Relay board enabling up to 64 relays to be connected to a single Raspberry Pi board. In a little documented stroke of luck the relay module has a separate loop to power the relay coils, that is the electromechanical part that makes the relay switch, and the Pi has a +5V pin to supply power directly from the USB power source. Here should be the Raspberry Pi as well as the relays and everything else that is water sensitive inside. Shouldn’t need anything else to protect the Pi. Relay control with Raspberry Pi and Python3. Pump - Connect your pump to a power source, run the black ground wire between slots B and C of relay module 1 (when the RPi sends a LOW signal of 0v to pin 1, this will close the circuit turning on the pump). To use the module from Python programs, first import it using: import RPi.GPIO as GPIO This way you can refer to all functions in the module using the … In this tutorial we are going to go over soldering the header to the Relay HAT, use Python with the included Pi.GPIO library to write code that triggers each relay, and go over the external relay connections and configuration options on the board. Wilmer Kluever. Active 2 years, 5 months ago. Raspberry Pi boards have 40 pins that you can use them to communicate with other components. contacts can switch up to 8A/48 VAC or 8A/24VDC. To configure the relay board with a Raspberry Pi I am assuming that you are running the latest version of Raspbian and have the ability to connect to your Pi through SSH with Putty and FTP with Filezilla, or directly with a keyboard and monitor, if you haven’t set-up your Pi yet then check out my getting started section. Step 1 : Controlling switches with Python. Now, let start the server application. If power is applied to the barrel connector, no other power supply is needed for the Raspberry Pi. Stacking boards? If the relay is to open, if the LED is also on, middle and right OUT pins are connected. What I’m curious about is that the relays on most relay boards are 5v relays, meaning they require 5v in order to “switch on.” How can you provide only 3.3v from the pi to the relays and expect that to be enough to switch them them? Discover the best Raspberry Pi 400 projects and guides! Each relay needs about 80 mA to turn on. Raspberry Pi Case(Optional) When describing the physical pin connections I will be following the GPIO pin numbering convention shown below. The LED is off there. If the GPIO interface of the Raspberry Pi is sufficient, you can also switch an LED when it gets dark. Via the Pi terminal, type: sudo apt-get install python-rpi.gpio. However, since the relay boards operate at 5v, another resistor between the IN pin on the relay board and GPIO on the Pi is recommended. In the terminal window pointing to the raspberry-pi-relay-timer folder (you changed to this folder with the last command you typed), execute the following command: python ./controller.py thank youuu, Hello. Breadboard 6. The 2 standalone pins on the relay module marked VCC and ground should go to the Pi's +5V and Ground pins. It all seemed to go wrong once I went down this route as the relays stopped doing anything. on: function(evt, cb) { 1. Pluggable connectors make the 8-RELAYS card easy to use when multiple cards are stacked up. I tested the voltage on the breadboard and it’s def working – I have it set to 5v on one side of the board and 3.3v on the other and both are correct. You probably already have it, but just to make sure. Relay screw terminal description: This board integrates three screw terminals, and each has three pins for connecting external circuits. (adsbygoogle = window.adsbygoogle || []).push({}); How to Connect an Electrical Conductivity Sensor to a Raspberry Pi. A bulb. Hi Chris If I recall, the coils in those 5v relays can draw around 30mA. Pluggable connectors make the 8-RELAYS card easy to use when multiple cards are stacked up. Is it possible to control relays if we are using thermal camera to tell if when will the relay gonna turn off f or on? Raspberry Pi Expansion Board, Power Relay The RPi Relay Board gives your Pi the ability to control high voltage/high current devices, easily makes normal home appliances become intelligent. It was developed by Ben Croston and released under an MIT free software license. (i do not power relays from the gpio header*) the higher current DC then throws the breaker by powering the coil. Right now, the server is only running because you started it manually. ... PINOUT connections for the Raspberry PI. ... PINOUT connections for the Raspberry PI. I have Raspberry Pi B+ and i just bought 8 channel relay. If you set 5V instead of 3.3V to VCC, you should definitely put one resistor each (~ 1kΩ) between the GPIOs and the IN pins. Home Automation is one of the popular DIY Projects that hobbyists and electronics enthusiasts love to work on. The GPIO pins on the pi cannot directly drive a relay (each gpio pin can only supply 15mA, not enough for a relay). Which means it could be a nice solution for controlling devices that couldn’t be directly controlled by IIC bus. Dec 11, 2020 #1 I bought a relay like this today for my raspberry pi, and I am encountering a very strange issue. Pay extra attention to the specifications of the relay and take, if possible, no dodgy parts from China (which doesn’t matter in the low-power range but at higher voltages you should spend a bit more and take proven products). After much head scratching it seemed that neither the AM2302 nor the relays would function using the power from the breadboard but only worked when connected back to the power out from the GPIO. Perfect add-on to your project when you have to control large number of loads. event : evt, It's a nice solution for controlling devices that can't be directly controlled by the Raspberry Pi's Digital I/Os (GPIO). To avoid wasting too many GPIOs on the Pi it pays off to purchase a GPIO port expander with more than 4 channels. Here is an image of the GPIO pins on the Raspberry Pi: First, I started out by hooking up the relay to the Raspberry Pi like so: The red wire (female to female) leads from the JD_VCC pin on the relay board to the 5V pin (pin 2) on the Raspberry Pi. I've always wanted to see how could a Raspberry PI could contribute to the IoT movement and home automation. I didn’t realize I should be keeping a max amperage of 3mA through these pins. Jumper Wires 9. Is that correct? Now transfer the code to your chosen folder on the Pi using an FTP client and then run the program using SSH or from the desktop using a Terminal. Read it now Wireframe issue 45. Raspberry-gpio-python or RPi.GPIO, is a Python module to control the GPIO interface on the Raspberry Pi. Therefore we cannot directly connect relay to raspberry pi and hence, we need a switching circuit for relay itself. While it’s easy to trigger GPIO ports, they can only emit 5V. Relay RPI. Description The PiRelay is a Raspberry Pi relay add-on board which provides a solution for controlling high current/voltage devices and makes your home appliances intelligent. To use the board on the PI, it should be enough to remove the jumper and then power 5V from an external power source to the JD-VCC pin and connect the 3.3V reference from the PI to the VCC pin. This might even be enough for a night light, I have to test it. At the end of last year I had become interested in the cool things being down with the Raspberry Pi, handheld video games systems, robots, light shows, servers, etc. The first thing that you need to do is set up the wiring so that you can programmatically flip the switch using our Raspberry Pi. The structure is very simple since all pins are labelled. I spend time away from home and the pi looking after the tempratures for the heating sometimes stops. The script sends the handshake sequence to GPIO2 which enables the board. If you are connecting more than 4 relays then it is probably necessary to power your relay board with a separate 5V supply. In order to do this, you need to understand How to Control a R… Also connect Pin 2 to VCC, and Pin 5 to GND on the Relay board. Stackable to 8 layers, the card can add up to 64 relays to each Raspberry Pi in a compact form factor. But this really did help me with it. What is the best way to get the Raspberry Pi 4 to control 40-50 relays? Therefore we cannot directly connect relay to raspberry pi and hence, we need a switching circuit for relay itself. sudo python piot_relay.py. They do have a transistor and a diode and I think they are for protection. In this case, the transistor can be used as the equivalent of a switch which is controlled by the GPIO pin. This tutorial can be used for both the 4 Channel Standard Relay HAT and the 2 Channel Pi Zero Relay HAT. Breadboard 8. But like many other peripherals on the Raspberry Pi Bluetooth also is disabled by default. Next, connect one of the 5v pins on the raspberry pi to the VCC pin on the relay. Introduction. Four relays with N.O. Raspberry Pi Expansion Board, Power Relay The RPi Relay Board gives your Pi the ability to control high voltage/high current devices, easily makes normal home appliances become intelligent. Discover the best Raspberry Pi 400 projects and guides! , Hi I have drilled a hole on the lower side and all the cables that have to go in or out of it. This post describe how to install a 4 channel Relay board on a Raspberry Pi and how to control it with Domoticz. } You can read more about this here: Autostart Python App on Raspberry Pi in a Terminal Window. Also what kind of transistor would be used? connecting the common to the NO normally open pin. Smart phone with app (described later in the post). Python is a beginner-friendly programming language that is used in schools, web development, scientific research, and in many other industries. Also connect Pin 2 to VCC, and Pin 5 to GND on the Relay board. The RPi.GPIO module is installed by default on recent versions of Raspbian Linux. 230V is life-threatening. If you want to connect devices with high voltages, you should either know exactly what you are doing or ask an electrician! Since the Pi only tolerates a maximum of 5V (the GPIOs even only 3.3V) without relays, there is the risk that the Pi could burn out. } Description The PiRelay is a Raspberry Pi relay add-on board which provides a solution for controlling high current/voltage devices and makes your home appliances intelligent. It also ensures that when the Pi is shutdown that the relay does not stay energized when connected to and external 5V power source. If you’re looking for everything you need to know about programming python on the Raspberry Pi, you can refer to my previous tutorial on it! Thanks . ... perhaps I should have provided more information. Python is a versatile and relatively easy to learn programming language. Now that we have a circuit connected we can go ahead and add some code for our Raspberry Pi relay control and test the connections. All the python code is available on my Hydropi GitHub Repository. I have Raspberry Pi B+ and i just bought 8 channel relay. callback: cb IN1 Control PIN for relay channel 1 - PIN 16 - BCM23 . } It is so flexible it will allow you to build web application as well as interface with hardware components connected to the Raspberry Pi. The opposite is also true when the GPIO pin is deactivated there is no voltage applied to the Base (B) pin and this effectively “opens the switch” and breaks the connection to Ground from the relay board. It’ll limit the drain to 2.5mA on that part of the circuit. On the Raspberry Pi the control circuit will be operated by our GPIO pins. Just put a 2kOhm resistor between Pi and relay board and you’ll be fine. Perfect add-on to your project when you have to control large number of loads. The Raspberry Pi Relay Board gives your Pi the ability to control high voltage/high current devices, easily making normal home appliances become intelligent. It is so flexible it will allow you to build web application as well as interface with hardware components connected to the Raspberry Pi. On the Raspberry Pi's pins: Now you can turn your Raspberry Pi on, and we'll begin the code. This issue we pay homage to some of the makers who are creating their own bit of movie fandom, whether that’s props, costumes, or a great-big Ecto-1. Pump - Connect your pump to a power source, run the black ground wire between slots B and C of relay module 1 (when the RPi sends a LOW signal of 0v to pin 1, this will close the circuit turning on the pump). Raspberry Pi. Am I on the right track? eval(ez_write_tag([[580,400],'tutorials_raspberrypi_com-medrectangle-3','ezslot_12',103,'0','0'])); On the other side are at each relay 3 connections (see picture below): Depending on whether the IN pin is a LOW (0V) or HIGH (3.3V or 5V) is applied either the switch between the centre and right, or Open centre and left. In order to close/break a 220V circuit, you need a relay. Micro USB Power Supply 4. You can make changes using the nano text editor : nano piot_relay.py. Thanks a lot of the helpful information. I'll cover some of the basics here. IN2 Control PIN for relay channel 2. Where VCC or ground are connected (middle or right/left) does not matter. Hey Rob, you can actually draw more than 3mA but it’s really hard to find a definitive answer. Closed (NC) and a Common, an important convention to note is that when a relay contact is normally open (NO) the relay is not energized. In addition, the components can be soldered to a hole grid once everything has been tested. I've always wanted to see how could a Raspberry PI could contribute to the IoT movement and home automation.