I'm using a water detection circuit similar to the one found here
I put it all together and it worked pretty well for a hobby project.
However I was wondering if I should be concerned about ESD on the input of the "sensor"
I prototyped it with a breadboard hence why the first part was a Through Hole but am planning on laying out a board so I could switch over to a Surface Mount part.
I was curious if changing this part is necessary or do the two capacitors that block out the DC from the sensor protect it form ESD as well?
Edit - Added additional thoughts.
I've decided to double footprint my prototype board with both the CD4093 (and include the ESP protection diodes both responses suggested) and also SN74LV132ADR (IC QUAD NAND GATE 14-SOIC)from Digikey.
That way I can compare the two and see if there are any other changes I should address.
I read though the HCMOS Design Considerations provide by dfowler7437 which lead me to the TI Logic Selection Guide After skimming over the first few diagrams I settled on the LVC family. I ordered some SN74LV132ADR and hope with the following changes I should be set.
I'll include a cheap 100mA regulator for the power input of the SN74LV132ADR. Now, since it's a different part from the reference design (and a different voltage 3.3V instead of 12V) will I need to change the R1 and C1 to a different value to maintain the same frequency? (I'm assuming the frequency is tuned to get the sensor to work around the capacitive value of water)
Also, Since I'm changing the NAND gate to a different voltage I believe I need to change from a P Channel to an N channel (and then invert the output from N2 into say N3 or N4) in order to get the N Channel to work with a different Gate voltage. Does this make sense?