sensors far 30 mt and more from arduino


I need to control from an arduino 4 different sensors which are far about 30 meters. I thought to use a ttl/rs232 converter with an arduino mega that gives me 4 serials but as I read the maximum signal I can manage with an rs232 cable is 15 mt. Is it possible to handle in some other way ?


It'll do a lot more than that, especially at lower baud rates and with decent cable. Fifteen meters is what the standard specifies but it's not a hard limit.

If you need more distance, RS-485 might be a viable alternative.

For long runs you could consider using wireless telemetry with an nRF24L01 or similar transceiver. It is considerably more complicated to set up, and the remote sensors will require a power source and a local processor. But running long wires gets to be a royal pain in the neck, especially if you have to go underground or through walls.