Finally my standalone system is (almost)ready, up and running. The board is based on an Atmega328-au and features an accelerometer and gyroscope as sensors. A micro sd card reader with a low-level shifter.
I’ve designed the following schematic, together with some help from the forum.
The whole thing just works like a charm, my measurements are proper and the data logging is OK, I don’t measure any noise at the regulators or whatever. The only thing I’m scared of is the following, the low level shifter is getting hot, very hot, and i guess it has to do with the following; when I connect a scope to 1Y and the ground I measure a oscillation close to 16Mhz (clockspeed), i guess this isn’t the aim. The complete board also needs 0,5Amps (I guess this has also to do with the oscilation)
Does anyone have any idea what the problem could be for getting this hot or can I neglect it? I need to measure for a longer period of time and thus the system should be reliable.
The print before reflow soldering;