TCS230 working without power or ground

Using Arduino Sensors
1

I am connecting a TCS230 sensor to an Arduino Uno R3 in order to read various colored lines on the floor. Recently I noticed (by accident) that the LEDs on the sensor remain on, and I can still read values from it, even if the 5V Vdd or the GND pins are disconnected, both together or separately. The other connections are 4 digital outputs from the Arduino, one digital input to the Arduino, and an active-low enable. This phenomenon is happening with both of the TCS230s that I have (one on a breadboard, the other soldered to a perfboard).

Does anyone have any idea why this would be happening? I've looked around the internet, but am at a loss. :confused:

2

Not without knowing which pin on the TCS230 is connected to which pin on Arduino and the program that controls the states of said pins.

3

Hi saderholm.
What is happening is that if you remove power and ground from the system, then the system becomes in an unknown state. If you are driving an output from the Arduino to the TCS230, its possible that the output is powering the module through some unintended circuit path. It's an interesting phenomenon and possibly worth exploring, but if you want reliable behavior, its best to keep the module powered.