Raspberry Pi: 8 Channel Relay + External Power Supply Tutorial and Example

Setup an 8 channel relay using an external power supply and a raspberry pi.

Details:
- Raspberry pi 2 B+
- 5v 8 Channel relay
- 5v 0.7A power supply ( was a cellphone charger but i cut the end off)
- 8 pin f/f ribbon cable
- single pin f/f cable

I've seen in forums that some people have unreliable relays while using the 3v pin on the Rpi, so you can switch it over to the 5v pin.

Python Test Script:

Link To Relay:

[twoporciento]

Hi, I'm familiar with these setup and use relays with external supply before with arduino. My project uses PIC Microcontroller running at 3.3V and 4 channel relay. I connect with external power supply JD-VCC to external source and Ground to external ground. I Connected the VCC to 3.3V of the PIC microcontroller. However, the relay(input 4) sometimes runs strange like not enough voltage is drawn, turning off and on quickly. My question is that the gpio from raspi going to input of relay is 3.3V? and Does running 3.3V on VCC ok? Because power seems low.

[moritz-rissel]

Great video! I tried many things but this one got me in the right direction. very cool!

[dgb]

This is one very clear and very well made video

[vladfriedman]

Great video, worked perfectly, except that I needed to connect the VCC pin to the 5V on the Raspberry pi B instead of the 3.3V.

[AJBK]

Why connect a seperate wire to VCC as that is connected to the I/O header (at least on mine.) the jumper is only their to connect Jc-VCC to Vcc to power the relays from the IO header.
Ah, you didn't use the VCC and GND on the I/O header.

[adamjaakik]

vielen lieben Dank gut erklärt, sehr gut und sehr sehr interessant !

[siddharth]

why was the single cable plugged into the 3V supply pin of RPI?

[dickman]

I've had to watch this more than I'd like to admit.

[viswanathnimmagadda]

I dont have a JD-VCC on my board, where can I connect the power supply?

[alexanderrohrer]

What conditions decide, whether the power supply of the Raspberry is sufficient or a external power source has to be added?

[aatmajbarbhaiya]

what if i have to use a 15-0-15 V at 300mA rating transformer connected to a IC L7805CV Voltage Regulator operating at 5V DC output?!

i did this but it resulted in a humming sound when the relay was turned ON, and heating of the IC circuit.

[sriharshareddy]

Hey Techplant, it was a informative video. I dont have a ground right next to the JD-Vcc pin, can I connect the ground of the 5V power source to the other ground pin which is along with IN1, IN2 pins? Kindly clarify. Thanks

[ralphgriffith]

Thanks for the great video! Can you please tell me the purpose of the jumper wire? I know in the video you said it powers the internal relay switches, but don't the relays require 5V? Instead, you're using the jumper to connect to a 3V pin on the RPi (I'm sure I'm the one confused). Also, I am trying to use a 12V external power supply due to the small 12V dosing pumps I'm wanting to use for pH control in a hydroponic system. Can I substitute a 12V external power supply as used in your example? TIA for any help.

[Felix-lrxv]

Does the py still need amperage for switching the relay with the external power supply?

[jamesmcbride]

Are you powering the pi through the relay board instead of powering the relay board through the pi, or are you using two power supplies?

[TCreatorO]

Very interesting, a really good followup video would be, if you showed how to make a touch screen GUI to activate each relay

[matthewbair]

Contrary to some, I actually enjoyed the music. What is the song?

Oh yeah, and this helped a lot. Thank you

[csc]

Just seeing this today, 3 years after you posted it 😄
I have a question: is the trigger a low signal for this kind of boards?
Thank you, very nice and clear video.

[radityawaliulu]

could you make video explain wiring relay 8 ch in Raspbery 3 B+

[talmaier]

Thanks for this video, helped me a lot! I have a 5V 3A power supply, can i use this single source for the RPi and the relay board as well?