ELEGOO 4 Channel DC 5V Relay Module with Optocoupler for Arduino UNO R3 MEGA 2560 1280 DSP ARM PIC AVR STM32 Raspberry Pi

I have just finished using this for a Raspberry PI project to control my living room and bedroom ceiling fans. This module works very well when connected properly to the RPi. There is a lot of misinformation on this product and the look-alikes. I measured the actual current usage based on my project and here are the facts:The current draw on a single 3.3V GPIO port to turn on a relay is 0.47mA only, not 16-20mA as given in the specs. The max current draw for a RPi GPIO port is rated at 16mA, so there is plenty of power to drive these relays. The relays are being driven by the 5V source, and the GPIO is only switching on the relay driver current.The increase on the main 5V power supply when a single GPIO port is activated is 53 mA. I did not measure this for 2 relays at the same time. The 53mA to turn on a relay is coming completely from the 5V power source, in my case a 2.5A wall wart connected to the microUSB connector, so this current does not strain the RPi at all, only the wall wart.To connect the RPi to this module, connect a 5V pin from the RPi to the JD-VCC connector on the module, and a RPi GND pin to the GND pin on the module just to the left of the JD-VCC pin. Leave the middle VCC pin unused.Connect a 3.3V pin from the RPi to the VCC pin on the 10-pin connector on the module. I also connected another RPi GND pin to the GND pin on this connector. Finally connect your GPIO pins to each of the 8 inputs on this 10-pin connector.

Great relay boards, I just have to get my dog to stop opening up any amazon package first. I think she get so excited she forgets to smell it first to see if it is a package of treats or toys for her. Once she gets the envelope or box torn open and takes out what is inside then she seems to stop and smell it then and if it is not her treats or toys she stops... .... so long story short both of my 8 channel relay board worked just fine. I tested them all 8 channels worked as expected. Just remember before you write up any negative reviews about these relay board are LOW active triggered not HIGH as you may be normally expecting. In fact all of these style relay board are ALL LOW ACTIVELY TRIGGERED no matter if it is a single channel or 16 channel relay board. Also so I have seen some negitive reviews about the contacts failing at less than 10 amp and less than 30 volts DC. You have to protect the contacts if the load you are switch is inductive and not just resistive. you can use a 1/2 watt 100 ohm resistor in series with a 0.1ufd , non polarized capactor rated at 1000 volts across your relay contact to help bleed off and suppress any arcing across these contact to protect them from welding closed. Hope this is helpful for you. if you are not well versed in electronics please read as much as you can so you can have more fun and less disappointments.

Great little board I am using as a lighting controller with an arduino + pc serial remote controlArduinoIDE codeconst int r1 = 10; //d-io 0-1 are tx/rxconst int r2 = 2;const int r3 = 3;const int r4 = 4;const int r5 = 5;const int r6 = 6;const int r7 = 7;const int r8 = 8;const int sr1 = 0;const int sr2 = 0;const int sr3 = 0;const int sr4 = 0;const int sr5 = 0;const int sr6 = 0;const int sr7 = 0;const int sr8 = 0;int incomingByte = 0;void setup(){ Serial.begin(9600);pinMode (r1, OUTPUT);pinMode (r2, OUTPUT);pinMode (r3, OUTPUT);pinMode (r4, OUTPUT);pinMode (r5, OUTPUT);pinMode (r6, OUTPUT);pinMode (r7, OUTPUT);pinMode (r8, OUTPUT); digitalWrite(r1, HIGH); //default all relays off digitalWrite(r2, HIGH); digitalWrite(r3, HIGH); digitalWrite(r4, HIGH); digitalWrite(r5, HIGH); digitalWrite(r6, HIGH); digitalWrite(r7, HIGH); digitalWrite(r8, HIGH);}void loop(){ int state; if (Serial.available() > 0) { // read the incoming byte: incomingByte = Serial.read(); } if (incomingByte >= 49) { if (incomingByte <= 56) { state = incomingByte - 48; if (state == 1) { digitalWrite(r1, HIGH); } else if (state == 2) { digitalWrite(r2, HIGH); } else if (state == 3) { digitalWrite(r3, HIGH); } else if (state == 4) { digitalWrite(r4, HIGH); } else if (state == 5) { digitalWrite(r5, HIGH); } else if (state == 6) { digitalWrite(r6, HIGH); } else if (state == 7) { digitalWrite(r7, HIGH); } else if (state == 8) { digitalWrite(r8, HIGH); } //delay(2000); Serial.print("I received: "); Serial.println(state); //delay(6000); incomingByte = 0; } } if (incomingByte == 43) // + as turn on all pins { digitalWrite(r1, LOW); digitalWrite(r2, LOW); digitalWrite(r3, LOW); digitalWrite(r4, LOW); digitalWrite(r5, LOW); digitalWrite(r6, LOW); digitalWrite(r7, LOW); digitalWrite(r8, LOW); } if (incomingByte == 45 // - as turn off all pins { digitalWrite(r1, HIGH); digitalWrite(r2, HIGH); digitalWrite(r3, HIGH); digitalWrite(r4, HIGH); digitalWrite(r5, HIGH); digitalWrite(r6, HIGH); digitalWrite(r7, HIGH); digitalWrite(r8, HIGH); } if (incomingByte == 97) // a = on { digitalWrite(r1, LOW); } if (incomingByte == 98) // b = on { digitalWrite(r2, LOW); } if (incomingByte == 99) // c = on { digitalWrite(r3, LOW); } if (incomingByte == 100) // d = on { digitalWrite(r4, LOW); } if (incomingByte == 101) // e = on { digitalWrite(r5, LOW); } if (incomingByte == 102) // f = on { digitalWrite(r6, LOW); } if (incomingByte == 103) // g = on { digitalWrite(r7, LOW); } if (incomingByte == 104) // h = on { digitalWrite(r8, LOW); } if (incomingByte <= 104) { if (incomingByte >= 97) { Serial.print("I received: "); Serial.println(incomingByte); incomingByte = 0; } } //delay(100);}

I pay extra for ELEGOO parts because they have given me good service in the past, and try to put in everything you need to get working quickly. For example they sent me connector wires and a small screwdriver, so I could screw/unscrew the terminal blocks.At first I accidentally over-voltaged this, at 12 VDC, and it did not work. Once I realized the issue, it worked perfectly.

Going to use this to control my blower motor in my car. After some setup got it to work great. after about five minutes with the blower on high it smoked the relay, could smell it burned. must have been too many amps for it. Going to have to use regular 30 amp relay. This was in no way the fault of the unit, I was testing to see what it would handle. Customer service was awesome, without asking they sent me 30amp replacements, which they didn't have to do since this was my mistake. The only contact with them was for a better understanding of the wiring schematics, which they emailed promptly to me. Seller is exceptional. If you need more than 10amps get their other unit. This one works well for other 12 volt accessories that do not require a lot of amps.

Not an elegoo product. Packaging is not good. All pins are in bent condition, all terminal blocks are rusted.

Working Good

Good enough