Created by
Created May 15, 2012
Last modified May 20, 2012
Tags 311   7414   7447   7490   count   infrared   led  


A functioning counting circuit. While the space between the IR LED and the IR Phototransistor is unblocked the number stays. When blocked, it increments by one.


This circuit is based upon the work by Richard & Sam as posted in their Youtube video in 2011 at

I want to build this circuit to track the number of times a train (and its cars) traverses a particular segment of track on my model railroad. I have this working on a breadboard setup powered by a YwRobot 5v power supply. Soon I will start adding the extra digits.

Please leave your comments below if you have any suggestions or questions. Be forewarned though, on the question front, I have zero training in this and only have at my disposal the same as you (youtube, google).


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