I am making a project which is going to have to be functional on a small musical stage so there will be audio and power cables lying around . There will also be a strobe light.
I am going to need to communicate one Pillar on the left side of the stage with the right Pillar on the right side of the stage with SPI. The distance will be about 3-4 meters .
The communication will be sent from the master to the slave only with no feedback.
Would 3-4 meters be ok for SPI?
Would it be better if I used a slower clock for the SPI?
Would it improve noise shielding if I used RCA or even shielded Mono jack audio cables to transmitt the SPI signal?
Also I got advised to make differential pair signals for each SPI wire (3 in total , could maybe make it 2 if I tied the shift register clock and shift register
latch to one pin) .I'm using HC595 shift registers.
If for each pin I sent the signal and a mirror of the signal using an inverter and at the reciever used an op amp in a differential configuration would that do the job?
I'm using an atmega32
Thanks in advance for any input.