QTR 8RC and esp32

Hi folks
i use QTR-MD-08RC Reflectance Sensor Array
connected to an ESP32 devKit

I just had “problems” with my sensor QTR that some others may have : i had good reading values when uploading the sketch RawValuesExample.ino given when adding library
Basicly, it is just reading some values and i had some :slight_smile:

But when tryong to read from QTRRCExample.ino (with calibration) i had no reading : either 2500 or 0 values

In fact, i was using 3.3V and since i used 5.5V, it works much better !

Maybe it could be useful for other people


I am glad to hear you are having better results now!

We do not expect using different voltage levels to have any impact on the performance of our second-generation QTR sensors since they should maintain a constant current through their IR emitters, keeping the emitters’ brightness constant, independent of the supply voltage. With that in mind, I suspect whatever issues you were having with 3.3V operation might had something to do with your calibration method, or there might have been some issue with your supply (e.g. it could not provide enough current to power the board).

- Patrick