I have a reservoir about 400 meters away from where the waterpump is located that fills the reservoir. I intend to make a sender and receiver unit that each consists of an UNO and HC-12 module. The sender gets its signal from a simple float switch which tells it to send the "SWITCH ON" signal to the receiver, which will switch the pump on until the reservoir is full.
My question, as a newbie, what pins do I employ on the sender? Can the UNO detect a simple short between two pins when the float switch closes the circuit?
And on the receiver, what hardware do I connect to the UNO in order for it to eventually actuate mains power into a 5A or 10A relay to take care of the waterpump powering up?
Your advice is appreciated.
PS - am I overdoing this application? Is there a cheaper / easier method to do this? When reckoning in all the hardware (waterproof cases, antennas, PCB's) it turns at roughly $40 per unit.
heinburgh:
My question, as a newbie, what pins do I employ on the sender? Can the UNO detect a simple short between two pins when the float switch closes the circuit?
Connect the switch between an I/O pin and GND. Set the I/O pin using pinMode(pinNumber, INPUT_PULLUP); and then the pin will read HIGH when the switch is open and LOW when it is closed.
And on the receiver, what hardware do I connect to the UNO in order for it to eventually actuate mains power into a 5A or 10A relay to take care of the waterpump powering up?
The Arduino should operate a relay which will then switch the power for the pump. be sure to get a relay that is capable of 2 to 4 times the normal motor current AND make sure it is intended for mains voltages. An Arduino cannot drive the coil of an electromechanical relay directly - there must be a transistor in between. You can buy relays on boards that already have the transistor or you can use a solid state relay.
You should incorporate into your code arrangements to deal with a failure of the radio system. A common arrangement is to send a message several times per second and if the messages don't arrive the receiver knows there is a problem.
And you might need 2-way communication so that the base unit can tell if the remote unit is working.
...R
Excellent. Appreciate your advice @Robin2. I'll let you know how I get on.