Anyone used an ESP 32 board with sn74hc595 to do IO expansion? What experience did you have? …any gotchas?
I do have a specific question also: the sn74hc595 seems to be designed for 5v logic, however (if I’ve interpreted the information correctly) the ‘1’ trigger voltage seems to be low enough that it will workout 3.3v logic. What have you all found?
I did find the sn74hc595 page in the ESPHome documentation, so it seems that if I get the circuit right, it should just work…
Thanks!
Indeed. Just works 
. Used it with a esp82xx but their should be around 
difference using a esp32 instead.
Actually it’s only a 
expansion without being very inventive and build a bigger circuit around it 
I thought I should feed back my experience. for the most part, absolutely worked as expected. I would like to highlight one stumbling block though: I followed the Arduino example page pointed to by the ESPhome docs (https://www.arduino.cc/en/Tutorial/Foundations/ShiftOut). It’s worth saying that if you follow the breadboard layout (as I did!), there’s an issue with the power supply decoupling capacitor; It should just be across the 5v and ground in order to stabilise the voltage during operation. If you do follow the breadboard layout, this puts the cap across the latchPin and ground, which causes the circuit to not work. The circuit diagram is correct, though.
