I'm trying to make a simple water tank level sensor. I've read lots of pages and I like this simple circuit using the 7 channel Darlington array IC ULN 2004 (Or the ULN2803 that have 8 channels), probes and leds. Link: http://electroschematics.com/5764/simple-water-level-indicator-2/
Probe A Bottom of tank Probe B Upper position of tank Probe C Middle position of tank Probe D Lower position of tank
So I made it yesterday and works like a charm! but I don't know how to connect to my Arduino UNO. I tried connecting to the digital input an analog but I don't realize where is the continuity to control into the arduino. I would like that when the led bright, send the input data to the arduino, and viceversa.
I would appreciate a lot your help. Thanks a lot,