September 8, 2019 at 11:05 am #62507
I have designed a custom board to use with Raspberry Pi and common 8 Relay Boards.
The design is based on the OSPi board.
Is uses an 74HC595 shift register.
It can be expanded using the same board.
The Pi is connected with the shift register with Data, Clock, Latch and OE.
The shift register is then connected with the common 8 Relay Board.
I attach some pictures of the PCB for anyone to check.
I also attach the .brd file for anyone to check/altern/use.
The problem at first was that I had to change the negative logic to positive logic because that 8 relay board I had laying around. I used this link.
Then I had another problem that is almost solved but I would apreciate any help because I am at dead end.
At first tests, when I connect anything to a power outlet or open a light in the house, the relays go like crazy. After some research, I added come capacitors to the 5v power jack that powers the relay board.
The problem is almost solved.
But today I noticed that for some reason, is I touch my macbook power jack to my iMac’s keyboard, the relays again go like crazy.
I think that the problem ocurres if I have at least on zone to run.
Can anyone suggest any fix?
Attachments:September 8, 2019 at 11:07 am #62513
The .brd file can be found here:
GeorgeSeptember 8, 2019 at 1:32 pm #62515
I forgot to mention the power supply. I use a pretty good 5v 6a power supply but I have also tried other 5v power supplies.September 9, 2019 at 7:05 am #62528
Here is a video on youtube showing the problem.September 26, 2019 at 11:54 pm #62721
from you schematic, it seems you have connected to the raspberry connector with the incorrect orientation. You have connected pins 26, 28, 20 and 34 rather than 17, 11, 13 and 15. Also you have no ground reference to you raspberry. You need to connect a common ground between your boards explaining why you get odd results when touching your keyboard.
BrettSeptember 28, 2019 at 6:09 am #62736
Hi bretskee and thanks for your reply.
The pins connected are in fact 13, 7, 15, 11. Not 26, 28, 20, 34.
Check the picture attached. You can see the traces.
Regarding the common ground, my board and the raspberry are powered from the same power supply. But I soldered a jumper cable between pin 6 of Pi and a ground of the board.
As expected it didn’t make any difference.
The board and the OSPi program runs as it is expected. No problems there.
The only problem is when my macbook power plug touch any metal near the board.
Today I noticed that even when the macbook power plug touches the metal enclosure of the OSPi power supply, again the relays are acting crazy like in the video.
Attachments:September 30, 2019 at 1:32 am #62772
OK, on the pin thing, i was going by your PCB screen print which is incorrect.
Its a bit hard to trace out your board traces and without a schematic for your board and your relay board, it is a bit hard to see exactly what is going on here. By the description of your problem, I still think it is a reference issue to do with you inverted logic.September 30, 2019 at 6:22 pm #62784
Do you have a schematic? As bretskee said, it’s a bit difficult to track your circuit from the board traces only. If you have schematic, it’s easier to see if there is any logic issues.
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