I'm using 3 Arduino Uno boards with Ethernet shields. Each is connected to my home Internet switch with an Ethernet cable. I assigned a different local IP address to each Arduino and gave each board a different MAC Address.
Each Uno is collecting temperature/humidity for a bedroom in my house. The data is sent to a MySQL Database using PHP/HTML.
They work fine for a while (5 minutes) and then they conflict each other. If I use one Arduino at a time it works fine, but I can't get them to work together.
Any idea how to solve the problem?