http://ConsultingJoe.com
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https://www.youtube.com/watch?v=Eo2B-H9YbDg
One way communication to a raspberry pi over a 485 serial bus and using GPIO pins to talk to a max485 chip to convert from ttl serial.
In my opinion these MAX485 chips or these particular breakout boards are not reliable.
http://consultingjoe.com
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https://www.youtube.com/watch?v=0OrdgGD8sC8