8-Relay Addon EMO-R8 I2C connector
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Hello,
I would like to use the "8-Relay Addon EMO-R8" with my own controller hardware. My device has a connector with the I2C signals: SDA, SCL, GND and 3.3V.I noticed that the connector on your main board UniPi has a 5V pin instead of the 3.3V pin which I have on my device. Do you think this could be a problem? What are the signals connected to the RJ14 connector of the 8-Relay module? Is the schematic of this board available?
Thanks, Ondrej
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Hello,
it should work OK but you also need to connect 5V to the power supply connector.
More on page 9 of https://files.unipi.technology/index.php/s/zTmrEbQEvifNd6W?path=%2FProducts%2FUniPi 1.1#pdfviewer
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Thanks Tomas, I will give it a try then.
Ondrej -
Hi Tomas,
I have 2 more questions:
- Is the pinout of the I2C RJ14 connector of the UniPi board identical to the connector of the relay board or are the pins swapped?
- Are there pull up resistors on the SDA and SCL lines of the I2C connector on the UniPi board, the relay board or both?
Ondrej
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Hello @ondrej1024 ,
- yes the connector is the same on both
- the 5V pull-ups are only at UniPi
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Could you also tell me what is the max current the relay board draws?
Thanks. -
Hello,
each relay takes about 60mA at 5V (you can double check the datasheet) and the rest is not important. So in total about 500mA.
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OK, good. So a single card could probably be safely powered from USB. I will try that.