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by 2uk
Sun Nov 17, 2019 12:21 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

pcmanbob wrote:
Sun Nov 17, 2019 12:06 pm
2uk wrote:
Sun Nov 17, 2019 11:56 am
if I connect IN to PI or ESP has the same function right?
I have no idea I don't use arduino's , if your project is arduino based I suggest you find an arduino forum.
thank you
by 2uk
Sun Nov 17, 2019 11:56 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

Correct what ? I gave you the circuit to connect the relay board to the pi gpio using the ULN2803A If you want to add a esp32 arduino to the mix that's down to you, as its not required to interface the pi gpio to the relay board. thank you, I want to link these relays via ESP32 to the Internet and ...
by 2uk
Sun Nov 17, 2019 11:37 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

yes the com is only there to provide a connection for the protection diodes to the supply voltage that the ULN2803A is switching the ground to, when switching inductive loads like motors, as you are only switching a couple of LED's you don't need it. I suggest you read the data sheet http://www.ti....
by 2uk
Sun Nov 17, 2019 10:58 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

If every thing works correctly the way you have it connected then you can use the ULN2803A between the pi gpio and the relay board. connected like this https://i.imgur.com/eJBUtSA.jpg you can of course use any gpio pins you want , but you must use a ULN2803A the A variant being suitable for use wit...
by 2uk
Sun Nov 17, 2019 9:36 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

A2982 seems to be the best solution for me, please advise me, in this case I can try to make a mini board that I will slip between the relays and use everything at 12V
by 2uk
Sun Nov 17, 2019 8:17 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

Ok try this. Connect 12V supply to vcc and ground. Connect 5V to com and the ground form the supply to IN pin You should see the LED light up and the relay should click. You need the 12V to actually power the relay coils. I managed to get it to work with a 12V400mA source by connecting VCC (+) GND ...
by 2uk
Sat Nov 16, 2019 11:23 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

I did not find a 12V source but, I connected the relay directly to a 9V power supply and switched it on. After that I linked VCC and IN to (+), GND to (-) nothing happened, I linked after VCC (+) and GND and IN (-) nothing. Measuring with the multimeter I get results from COM (+) and IN (-) but I do...
by 2uk
Sat Nov 16, 2019 9:24 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

Re: 8ch relay 12V

It very much depends upon the operating mode of the relay board. If your diagram is correct then it would suggest you need to supply a voltage to the In pins and the board has a common ground, in which case no you can't use a uln2803 as that chip provides a ground on each output that is switched by...
by 2uk
Sat Nov 16, 2019 8:48 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 984

8ch relay 12V

I bought this product https://www.amazon.de/gp/product/B06XFG85MK/ref=ppx_yo_dt_b_asin_image_o07_s00?ie=UTF8&psc=1 , in the description it was written that it is 5V and I hoped that I can use it directly without other components, I discovered after that the relays are 12V I made a complaint but I st...
by 2uk
Sun May 26, 2019 7:44 pm
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

sorry for the late response here is the final product , I wood like if some one corrects it (if I did something wrong) thank you the ling to file is here https://easyeda.com/editor#id=|aba6b55daa8d45808a3638979cb9a51e|ba8c9ba3f7d04d11ada6e2d6013baf97|20f483a5286548af8a82ccd3309482bd|8632d73945e84abe...
by 2uk
Sun May 05, 2019 7:14 pm
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

So hi all , Here I am again , is not easy to find the perfect components and the perfect order for them , I am doing it here https://easyeda.com/editor#id=|682545b629214b6a909fe0ce8364f30c|4e56a6b5ce234dfb8a0027508d5e1622 if some one want to help me a little I will appreciate , I an doing it on 8x5 ...
by 2uk
Sun Apr 21, 2019 8:26 am
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

Problem 1: connect to either anode or cathode, my preference is usually on the anode side. but may change during the PCB layout. Problem 2: if you still want to use a relay, then the board space will get bigger. You may group your outputs depending on the load you want to connect. low amperage modu...
by 2uk
Sun Apr 21, 2019 2:40 am
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

hi all sorry for my absence , Just got a lot on my head and since I do this as Hobby needed to wait, so I came up with this schematic Schematic3.jpg Schematic3.jpg I have 3 problems > Problem 1 - can I connect the Resistor on catode or anode ? as I have seen on a few examples on Internet it is not i...
by 2uk
Sat Apr 13, 2019 11:50 am
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

It seems that Echo software uses wiringpi, and wiringpi supports MCP23017 so it may be possible. http://wiringpi.com/extensions/i2c-mcp23008-mcp23017/ nice to know thank you, than I have the next question "how to I connect 2 of them ? " on internet I find only how to connect 1 thx :) I am thinking ...
by 2uk
Fri Apr 12, 2019 2:05 pm
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

It seems that Echo software uses wiringpi, and wiringpi supports MCP23017 so it may be possible. http://wiringpi.com/extensions/i2c-mcp23008-mcp23017/ nice to know thank you, than I have the next question "how to I connect 2 of them ? " on internet I find only how to connect 1 thx :) I am thinking ...
by 2uk
Wed Apr 10, 2019 6:24 pm
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

the LED is optional the resistor I am not shore The resistor is necessary, to control the current through the opto's LED I am not sure how to calculate the resistor so the PC 817 is rated 6V at 50mA http://html.alldatasheet.com/html-pdf/43368/SHARP/PC817/511/4/PC817.html tha PI suplys 5v at 300mA I...
by 2uk
Wed Apr 10, 2019 3:08 pm
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

Re: 26 GPIO to drive 26 Optocoplers

Wow , thank you very much for all the answers , sorry if I missed information about this project . so I want to use them all as outputs, I will drive Optocuplers to switch the status from my house electronics :) (windows and doors to open A/C , so I wold use the PI with an Amazon Alexa software and ...
by 2uk
Mon Apr 08, 2019 6:52 pm
Forum: Automation, sensing and robotics
Topic: 26 GPIO to drive 26 Optocoplers
Replies: 17
Views: 2110

26 GPIO to drive 26 Optocoplers

Hello to all I have read that the PI 3 B+ has 26 GPIO and that they can be reprogrammed (is that true?) than my question will be Can I use all 26 GPIOs (GPIO 2,3,4,17,27,22,10,9,11,5,6,13,19,26,21,20,16,12,7,8,25,24,23,18,15,14) (Pins 3,5,7,11,13,15,19,21,23,29,31,33,35,37,8,10,12,16,18,22,24,26,32,...

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