Where Do All These Wires Go? (FOMOphobia)

I was trying to get a handle on the multitude of serial connections and power connections and whatnots for FOMOphobia.

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As usual, I made a drawing. Diagrammatically, each module would look like this. Mostly serial communication from the RPi to the two displays with the GPIO pins controlling a relay that triggers the bell.

The logic voltage converters maybe need a word of explanation: In old serial communications, voltage could be anywhere from 5 to 15 volts DC. In the Raspberry Pi, the voltage on the serial port is 3.3 volts DC.  I will either need to build or buy a little device based on the MAX3232 chip to convert serial voltage to and from the RPi’s 3.3VDC to an acceptible TTL voltage.

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An additional RPi monitors the server for data for the printer.

Simple as that.

 

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