Coin Sensor

Thread Starter


Joined Jul 3, 2011
Hi , I look for helping about Coin sensor , I will make a piggy bank.
But I don't know how to detecting a coin.
I want to read a value of the coin only.
Someone suggest me to use Photo Interrupter.
Could you suggest me how to use Photo Interrupter to be a Coin Sensor?

Thank you. :)


Joined Apr 5, 2008

A photo interupter will not tell you the value of the coin.
It can only tell you how many coins have passed.



Joined Sep 7, 2009
There are a couple of methods. I've done one which will only really tell the difference between 2 coin types and only if they are quite different sizes. It works well for UK 1p and 2p coins for example. The coins roll down a ramp from a position where they are stationary at the top. The photointerrupter further down the ramp times how long they block the sensor so a short time is the smaller coin.

The other method is to have as many sensors as there are sizes of coins and have them in a line down the ramp so that the top of each size of coin blocks at least one sensor.