LED in line of analog output to reduce 5V to 3.3V

[mirasderbissalin]

Hello everyone!

I'm using a blue pill board for some stuff, its main sensor is GY-61 analog accelerometer. I mostly need resolution in the center, can I power GY-61 from 5V and put a red LED between the analog output of GY-61 and ADC of blue pill to drop the voltage to acceptable levels? I realize I won't have the first few hundreds of values, but I don't care all that much bout them. Is LED voltage drop linear?

I understand LED will convert some current into light, but in my understanding, ADC input is almost infinite impedance, right?

[hammy]

This won’t work , use a voltage divider to reduce the output to 3.3v

[mirasderbissalin]

hammy:
This won’t work , use a voltage divider to reduce the output to 3.3v

Voltage divider won't increase the resolution in a given segment, I can just power it from 3.3. Why it won't work? Too much output impedance?

[wvmarle]

An LEDs voltage drop (like with all diodes) is very far from linear.

Get a 3.3V regulator to power your sensor, and you likely need level shifters in the communication lines as well.

[Idahowalker]

When, in the past, I used a STM32 Bluepill, their are clear markings on the pinout as to which pins are 5V tolerant.