Rain Gauge Reed Switch Interference

Other Hardware Sensors
1

I created a weather station with an Arduino Pro Mini.

It has a DHT22, an anemometer, several I2C sensors, and a standard reed switch raingauge:
RainWise Rainew111.
The rain gauge has a single reed switch circuit, and a 60 foot coiled cable, and is calculated using an interrupt on the pro mini.

Arguably the easiest component to implement should be the rain gauge, but I am getting occasional spikes of values.
The whole system has been working fairly well, though I did notice that the rain gauge would suddenly register large inaccurate values at times. I traced this to my ham radio, which is located a short distance from the station.
After adding some clip on ferrite beads, and after some testing at different frequencies, the issue seems to have gone away, at least for ham radio frequencies.

However, today at 9:24AM, when I was not even home, the device suddenly showed several spikes of activity. Including one cycle of 114 clicks, which is several inches of rain in about 8 seconds. This is after about a week of working flawlessly.

Would grounding the whole rig help? Currently it is being charged with a solar panel.

I have attached the relevant log data from when the issue occurred.

relevantlogs.txt (2.16 KB)

2

Did you use a pull up/down resistor on the reed switch pin, and what is the value.
Try a 100n cap from Arduino pin to ground, close to the Arduino pin.
Leo..

3

As per a representative from the company: "Our tipping bucket gauge utilizes a normally open reed that closes for approximately 90 milliseconds during a tip."

I am not using any any pullup resistors other than the internal pullup when I set the interrupt.

pinMode(RainIRQ_PIN, INPUT_PULLUP);

I can try the cap.

4

So you did connect the reed between pin and ground, not between pin and 5volt.

A stronger pull than the internal one might be required for that length of cable.
If the cap doesn't help, try a 1k pull up resistor between pin and 5volt.
You can still keep the internal pull up active.
Leo..

5

Thanks Leo, I will try these things.