i have 30amp motors and was planning on using ssr. This is because the high voltage we apply to the relay can cause it to burn out if it returns to the Arduino board. Did you measure the current from Arduino digital output to drive the relay IN? 2) If there is not led in series with the drive pin, then add another resistor across R1 to reduce the series resistance and so increase the current available from you 3.3V drive. It is sometimes more convenient to use 12V relays driven by a 5V Ardunio board. Not enough for a whole house. 12v * 0.75 = 9v. This discussion also has information on choosing snubbers. You may have a 12V battery supply or need to use 12V for some other part of the circuit, or the lower current used by the 12V relay coils may be a consideration. The switching contacts of a relay are completely isolated from the coil, and hence from the Arduino. Choosing a relay to control outlets from Arduino. The solution to these problems is to add a snubber network. However it is not suitable if you are using a 9V or 12V supply due to the limitations of Arduino's on-board regulator. c) Four (4) relay shields using a separate supply. Both the UNO and the Mega have a polyfuse on the USB supply input. 1. Here are two examples (the first one from DX.COM's website). It the image above, the top terminal is the NO one the centre terminal is the COM and the bottom terminal is the NC one. However I suggest you measure the actual current needed to drive the inputs of any 8 channel board you use. 9vdc (9 Volt DC) Relay - DPDT PCB 8-Pin Mount - Non-Latching Non-Polarized Electronic Low Sign… The 12v adaptor is used for powering the circuit. The only link is by the magnetic field. There are a number of boards available:-. Share it with us! This article has some information on Solid State Relays Common Precautions. 16 relays at 33mA each coil is about 530mA, This greater than the 500mA USB ports normally provide but you could use a USB Wall adapter instead, say a 1A or 2A one, and power the Arduino from it and then use the 5V Arduino output to power the relays. About: I am always making electronic stuff. It is also not the case if you are driving a 5V relay module from a 3.3V Arduino board like the Due or Fio or SparkFun's FioV3. But most do not have any circuit diagrams available. Prime members enjoy FREE Delivery and exclusive access to music, movies, TV shows, original audio series, and Kindle books. d) Separate multi-relay 5V modules high triggered and low triggered, e) Separate multi-relay 12V modules high triggered and low triggered, f) Modifications for Driving a 5V relay module from a 3.3V Arduino board. This tutorial, Home Automation for Beginners, shows you step by step and also shows you how to build a custom Android App to control the relays. It is a bit hard to see what the circuit on the board is, but I assume there is at least a transistor driver to switch the relays. The Arduino can be programmed to turn on the relay when a certain event occurs, for example when the temperature of a thermistor gets higher than 30°C. a) Make sure the relay is controlled by DC volts 3 volts and up. Notice that the maximum DC voltage that can handled is much less then the AC rating. While designs vary, total switched power is usually less than 10 VA (volts x Amps < 10). A relay accomplishes this by using the 5V outputted from an Arduino pin to energize the electromagnet which in turn closes an internal, physical switch to turn on or off a higher power circuit. Arduino relay circuit and Arduino relay code:In this video we’ll learn how to use a SainSmart 4-Channel 5V relay module with an Arduino. When the relay operates it connects these two terminals together and joins the wire you just cut and your RGB strip turns on (if you have already turn on the 12V 2.0amp supply). The specification for the SainSmart say each channel needs 15mA to 20mA to drive it. Hi! Try connecting the Relay's VCC to the Arduino's VIN, which would be the 9v. 2. if 200mA is applied ,do i need to switch it via some kind of power tunner? The max switching power is 70W DC. Some solid state relays have AC control inputs of higher voltages instead on DC control inputs. A Relay is a device that helps microcontrollers (or microcontroller based boards) like Arduino to switch on or off different household appliances like motors, lights, water heaters, television and fans etc. 1. so if i want to use all 16 Relays at once, does the EXTERNAL 5V power supply to the Realy board makes any difference/help for Arduino board? The Arduino digital outputs can only supply +5V (or +3.3V) and less than 40mA max. Do a search on “flyback diode” for more details on this. e) Solid State relays are best suited for resistive loads like heating elements. How to test a car relay with a 9v battery. In Seeed Studio's 4 channel relay board, the relays are controlled by D4,D5,D6 and D7 so you can just plug this relay shield on top the Bluetooh Shield V2 to get a complete remote control of up to 4 relays controlled by Android and pfodApp. 29 ($125.80/100 cm) Get it as soon as Thu, Jan 7. Run CAT5 cable back to Arduino, one pair for +5V and Arduino ground (NOT connected on the relay end if you have opto-isolated relays), One pair for each signal, with one wire connected to ground at Arduino, the far end unconnected; Run the Arduino from a separate 9V supply, not USB connected to a computer However, there are applications where a mechanical switch contact may be required to routinely handle currents below normal wetting current limits (for instance, if a mechanical selector switch needs to open or close a digital logic or analog electronic circuit where the current value is extremely small). Yes that is possible. Should only be a 1 or 2mA. It can be directly controlled by Arduino/Seeeduino through digital IOs with external 9V supply. This happens most commonly if you are switching inductive loads, like motors, ceiling fans, etc, but can also happen when switching incandescent lights and is caused either by the contacts welding close due to high initial current OR arcing on opening and continuing to pass current. There are two common modifications for 3.3V operation of a 5V relay board:-. Connecting these relay modules to the Arduino's 5V pin means both the trigger current (IN) and the current to drive the relay coil are being supplied by the Arduino board. 9v battery negative - Relay switch 1 NC & Relay switch 2 NC Each relay switch has three inputs NO (Normally open),COM (Common) and NC (Normally closed) In this project, both wires from the motor will connect to both of the COM (middle) inputs of the relay switches. The Arduino has a 1A resetting fuse in the 5V line but you should be OK at 530mA + some trigger drive current per relay. The detail instruction, code, wiring diagram, video tutorial, line-by-line code explanation are provided to help you quickly get started with Arduino. Note that the Arduino is being powered by 12V via the plug in power. If you want more the 4 relays then there are a number of multi-relay modules available. 1) If the drive circuit has a led in series with it, i.e. Arduino, is protected from relay circuit. Use pfodDesigner to design the Android menu and generate all the code you need. For the optically isolated relay that is about 4mA and perhaps a bit more for the non-isolated one. ESP8266-018) FET Sheilds9) Solid State RelaysFinally there small section on Help My Relay Stopped Working (RC Snubbers). That VCC is for the 5V supply from Arduino. Reply I used 5V Vcc, and series resistor 10 ohm using common emitter configuration, the problem is: whatever the values of Rc or Vcc, I didnt get the required output ( Ic ~1A, and V-lamp 0f 1.2 V)! Hi! That's the bare minimum that is needed for the relay to activate. When a digital output is turned off it does not go open circuit, rather it connect the output pin to GND via a very low resistance. In this module the JD-Vcc and the Vcc connections both have the same GND point so only one ground connection is needed and no jumper is needed. If you can hear it click when it opens but the motor keep running then the contact are probably arcing. The shield powers the Arduino board. The trigger GND is connected to Arduino GND and D4 is connected to IN1 to drive relay 1. The connections between the relay module and the Arduino are really simple: GND: goes to ground; IN1: controls the first relay (it will be connected to an Arduino digital pin) IN2: controls the second relay (it should be connected to an Arduino digital pin if you are using this second relay. This will require some careful soldering. The solid state relay can be controlled with 3V, so is suitable for the 3.3V arduino boards. FET switches do not have this problem and can be used to switch very low currents. All commercial relay modules should already have the clamping diode fitted across the relay coil. The Shield features four relays, each relay provides 2 pole changeover contacts (NO and NC); in order to increase the current limit of each output the 2 changeover contacts have been put in parallel. ... Normal silver or copper alloy contacts will not provide reliable operation if used in such low-current service!” (http://www3.eng.cam.ac.uk/DesignOffice/mdp/electric_web/Digital/DIGI_4.html ). One final point about drive 5V relay modules from 3.3V Arduino boards. But for this, we will use the relay module designed for Arduino. Indeed that is just what the 4 channel relay shield from Seeed Studio does. After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. b) Single 5V power relays powered from the Arduino board's 5V supply. Any wiring to the mains power should only be done by a qualified electrician. From the datasheet for the SRD-05VDC-SL-C you can read that the relay coil takes ~72mA to operate. (A 9 volt AC adapter also works.) Control 8 relays, plus 2 servos, completely independently AND simultaneously with an ARDUINO 'Nano' and a simple sketch based on Object Oriented Programming and State Machines methods. The one shown above will switch a load of up to 40Amps from a 24 to 380V AC supply. So for either board, connect the relay GND to one of Arduino's GND pins and the relay 5V or Arduino's 5V pin and the relay IN to one of Arduino digital outputs, say D4. Note: in this case you should cut off the reset pin from the relay shield as it is driven by the RS-232 flow control on the Xbee socket. I actually did this testing using an UNO board. In that case, then when the Arduino output pin is high there may be 12V applied to it from the relay module. Using this approach you would power the SIM900 from the Arduino +5V (plug the SIM900 into the prototype shield header) and also wire the relay +5V to the prototype shield 5V rail. Removing the jumper lets you have isolated supplies, one for the the Arduino and another completely separate one for the relays. At the right hand end is the JD-VCC pin which is for the 12V for the relay coils. (http://en.wikipedia.org/wiki/Flyback_diode for example). (for switching between a solar power and main grid power lines). If i would use 5V 16 Channel relay board and switch it from Arduino: 1. use external power for 16xRelay board - Can i switch with Arduino all 16 Relays at once? Contact pfod.com.au via support if you have any problems. 4) Separate multi-relay 5V modules high triggered and low triggered 5) Separate multi-relay 12V modules high triggered and low triggered 6) Modifications for Driving a 5V relay module from a 3.3V Arduino board7) High/Low Triggered Relays for Use with 3.3V boards, e.g. Notice the Gnd and VCC near the IN terminals. In my case the relay did operate with a 3.3V input and only draw 1mA. There are a number of different single 5V relay modules available on-line. Typically with 8 relays but some with 16 relays. Arduino Uno boards can supply about 20mA. If you are looking for a simple way to switch these relays on and off from your Android mobile, via bluetooth, wifi or SMS, with optional 128 bit security, check out pfodDesigner (www.pfod.com.au) and this instructable Code generator for custom Android/Arduino menus to switch Arduino outputs on and off Absolutely NO programming required. In any case DO NOT use your computer's USB to power the Mega with the SIM900 connected as the computer's USB ports are limited to 500mA. I would keep the the total to 100mA or less, myself. The shield powers the Arduino board. The coil resistance is about 500 ohms so when D7 is high (+5V) most of the voltage appears across the coil (I.e ~4.7V ) (search for Ohm's Law or checkout Sparkfun's tutorial) The “pull in” voltage on the datasheet for the TRR-1A 5V reed relay is 3.75V which means any voltage higher that than must close the contacts so 4.7V is more then enough to ensure the relay operates. Next apply 3.3V to the IN input and check that the relay operates. I hope you can help me, I'm really a noob with this. The problem is that most Arduino boards use a linear regulator to drop that 9V to 5V. This is also an issue if you are driving 5V relay module from a 3.3V Arduino board like the Due or Fio or SparkFun's FioV3. 9-Volt battery) and the Arduino (USB cable) OR the Arduino board itself supplies the power but the relay is a 5-Volt one. This video shows how to control 16 AC or DC load using the 16 Channel Relay and Arduino. If you are only switching a few milliamps, for example by putting a relay across a low voltage garage door push-button, you should use a reed relay (or a relay with gold contacts) as the power relays need a “wetting current” to break through the surface film resistance and will not switch very small currents reliably. What most people are failing to realize is with the optical isolated multi relay boards all the opto's high side are tied together through the 5 volt coming from the Arduino board. The problem is the circuit was designed for 5V to drive the optical isolator U1, and U1 may not be getting sufficient current from your 3.3V Arduino's output. i'm a beginner and trying to use the same principle to drive an IR lamp (R=3.1 ohm, Vmax=1.4, Imax=1.14 Amps) using arduino Uno and Tip120. KeeYees 5pcs 1 Channel 5V Relay Module Board Shield KY-019 LED Indicator for Arduino + 3pcs 20CM 10Pin Female Male Jumper Wires 4.5 out of 5 stars 37 $10.99 $ 10 . For a 10amp load, the relay needs to get rid of about 16Watts of heat. Operating Current As opposed to voltage, which is “forced”, current is the draw a circuit can place on a power source e.g. but not the right option? These relays will handle most devices used in homes except the highest powered ones like room heaters, stoves, motors. If your relay board does not operate you may have to find a series resistor in the input circuit and reduce its value as described above. I expect this is an error as all the modules I have measured need <5mA to drive them. The led was using up about 2V so shorting it out means now you only need about 3V instead of 5V to drive the relay. The jumper is connecting these two grounds together so you can use it just like the left hand board. So this in will not harm the 3.3V microprocessor board. I used the UNO 5V and GND pins to power the relay module and then measure the open circuit IN voltage. If you have ever had in mind the desire to control one of your real-world appliances with an Arduino, here is a good Arduino relay project that shows you how you can, for example, use the combination of elements shown in this post to build a bridge from the Arduino layer to any other appliances with higher power rating.