When using a transistor as a saturated switch like this the base current is just (Vmcu_pin - Vbe) / Rbase You just need t ensure that this current is much greater than the collector current divided by the hfe of the transistor. A good rule of thumb is to make the base current greater than 1/10 or 1/...

Use a random number as the ASCII code for each character in the string. E.g. (not tested) // Generate random string in "str" of length "len" chars static void get_random_string(char *str, unsigned int len) { unsigned int i; // reseed the random number generator srand(time(NULL)); for (i = 0; i < len...

I'm assuming the transistor emitter is connected to ground here. If "the current at the collector is very low" then use a bigger base resistor than 2k (e.g 10k or higher) and see if this makes a difference to the MCU pin voltage. If pin still low do the same test with nothing connected to the MCU pi...

Unless your MCU pin is 5 volt tolerant you can't use it directly to switch a P channel MOSFET as for the NMOSFET to be off the gate needs to be pulled up to the battery voltage. Hence the use of a NPN transistor in the diagram (could also have been a N channel MOSFET).

Hi ayavilevich, By "switching the divider", do you mean using a transistor of some kind or is there a better way? Yes, or better than a transistor in this case use a MOSFET. A transistor will have a VCE saturation voltage where as the MOSFET will act more like a switch with just a small resistance (...

Hi ayavilevich, I afraid can't find data for the ADC input impedance unfortunately. The original problem posted is probably much more to do with ADC calibration (that WiFive links to) than ADC input impedance. In your case the ADC input impedance will be in parallel with your 20k resistor. But the A...

I have this problem also and none of the steps above work for me. Trev@Trev-PC MSYS /c/esp/hello_world $ make menuconfig make[1]: Entering directory '/c/esp/esp-idf/tools/kconfig' make[1]: *** No rule to make target '/usr/include/sys/_locale.h', needed by 'mconf.o'. Stop. make[1]: Leaving directory ...

What value resistors are you using in the potential divider? How are you calculating the voltage values from the ADC binary value? One of the things to consider is that the divider will add series impedance which will act with the ADC input impedance to form another divider. This is why buffers are ...