Hi everyone,

I'm currently working on an ECG Simulator from SW website. It uses a 555 timer to generate the signal.

What I'm trying to do is to read the signal with an ESP32 through an non-inverting amplifier circuit to bring up the voltage to around 2.8V.

I used D4 which is an ADC.

However, when I open the serial plotter the signal is very distorted.

Is the ESP32 able to read negative voltages? Because as shown in the picture there are negative voltages.

I used an op-amp with a gain of 3.3 using a 33k and a 10k resistor and a TL071.

As said in the datasheet the voltage difference between V+ and V- should be at least 10V, I used a 12V power supply.

Did I do something wrong or is there an error somewhere?

I also simulated the generator circuit and gave a normal signal. I also amplifier the signal and it looked fine on LTSpice.

 

Is the ESP32 able to read negative voltages?

No.

As said in the datasheet the voltage difference between V+ and V- should be at least 10V, I used a 12V power supply.

Did I do something wrong or is there an error somewhere?

I also simulated the generator circuit and gave a normal signal. I also amplifier the signal and it looked fine on LTSpice.

Your simulation is meaningless. You say you're using a 12V supply, but in LTspice, you're using 5V and you're using LM741 which are useless with a 5V supply.

The picture of your breadboard is equally useless.