I do not know how this happened, but when connecting the muscle activity sensor to additional batteries, it burst into flames, a cloud of gray smoke formed, upon subsequent inspection of the sensor it turned out that the part indicated by the arrow broke out, it charred, the yellow shell peeled off and this part turned black, so my question is whether it is possible to save the sensor, in general, the sensor it also works when connected to the arduino, it gives out some values, constantly about the same, I tried to listen to the sensor with a voltmeter, it gives out values and these values disappear quickly, does this mean that the sensor is alive? What actions should I take? (I apologize in advance if something is written crookedly, English is not my native lang
The yellow part is a tantalum capacitor. They burn out in the way you describe if you connect the power the wrong way round. There's a reasonable chance that the protection diodes within the sensor IC's saved them. Let's say 50/50. The fact that your sensor still does 'something' is a good sign. Whether it's reliable anymore - maybe, maybe not. Assuming that this is a hobby project, just proceed and see if the values make sense, if so, shrug and move on. If not, get a new module.
You could try replacing the yellow part, but it involves SMD soldering; it's not insanely difficult, but will be challenging if it's your first time doing something like this. The sensor as such will likely function OK-ish without it; you could get a couple of 220uF electrolytic capacitors and connect one across the power supply pins of the sensor board.
