Electronic – arduino – Connecting RJ11 plug output to Arduino

arduinowiring

Newbie question. I have a Davis 7852 Rain collector that measures Rainfall using a Reed switch. The output comes via an RJ11 plug with following pinout

  • Black – Unused
  • Red – Switch terminal
  • Green & Yellow- Switch terminal

I am assuming that when Rain tips the collector, a circuit is completed and a voltage output will come on these wires. My plan as of now is

  • crimp the wire – tip the switch and measure wire voltages using a multimeter
  • There would be a high voltage wire and another would be low voltage
  • Now I have to measure the difference between high voltage and low voltage wires
    The difference will tell if the switch has been flipped.

Does the plan look reasonable? How can I interface these wires to Arduino input pins? Any precautions in pushing the RJ11 wires to Arduino?

EDIT

EDIT-2 (in reponse to Michael)

Much Thanks. I am reading electronics text to work out this circuit 😀

EDIT-3
Thanks. figured out the schematics 😀

Best Answer

The rain collector appears to have only a reed switch contact closure output. The collector itself will not produce voltages on the wires. Instead you have to connect the reed switch contact wires into a circuit that puts a bias on the wires that can be detected by the Arduino.

Since the wires are most likely running from outdoors (wet rain location) to indoors (dry Arduino location) it is a good idea to prepare some additional protection circuitry before the input to the Arduino so that if the wires experience some electrical disturbance it does not knock out your MCU board. You could try the following circuit as a starting place to hook up the rain collector reed switch.

enter image description here

Related Topic