So I’ve been struggling with a hardware change to my pool monitor. Ever since I upgraded and expanded the system (still a work in progress) my thermistor readings have been very erratic (see graph below) and 2-3 °F higher than they should be. Some of this was due to software issues that I’ve since fixed, but some has remained, no matter the software I’m using. This morning I decided to remove the JSN-SR04T Rangefinder and all of a sudden my temperature readings went back to normal. The Rangefinder board was on the breadboard, but was not wired up to the sensor or being called by the software. So what on earth is going on? My Fritzing diagram is below too.
The rangefinder is powered by the Vin pin since it’s a 5V device. Is there some sort of cross-talk happening here that I don’t see?