I have a 3v relay (https://www.amazon.com/dp/B01FK11HV4) that is not consistently staying closed, and I’m troubleshooting why that is. The behavior in the relay is that the indicator lights would remain lit, but the relay itself would cycle fairly frequently and open the circuit it was controlling (a pool heater).
As part of troubleshooting, with the relay removed from the system, I’ve been monitoring supply and ground voltage in a thermistor voltage divider that measures the exhaust temperature of the heater (to track how long it’s on). There are some fairly erratic readings in the supply voltage (3.3v) measured at the location X’ed blue, but not at the supply voltage (same 3.3v, but upstream of a couple breadboard connections) immediately at the photon 3v3 pin (X’d green).
The chart below is the analog read value of a few points. The colors correlate to the measurement locations drawn on with X’s in the fritzing diagram. So the supply voltage right at the pin doesn’t fluctuate, but after a couple internal connections, I get pretty big swings. Once over the weekend it went as low as 2400.
any idea what’s causing this behavior? I’m speculating it’s possibly the breadboard connections, and considering upgrading to a soldered perfboard instead of the more flexible breadboard. Does this seem like it would fix it?
absent any direct data on the relay circuit (it’s next on my list to get), does it seem like a similar thing could be happening there, causing the cycling behavior I was seeing?