Coin counter using laser and LDR project

Hello,
Im working on a school project for my second year of learning electronic.
My project is a kind of a safe which count all kinds of coins.
This project is based on laser beam or LED at one side and a LDR (light detector resistor) on the other side. Once a coin droped in, the safe count it

I would appreciate any help with the counting system schematic that count every time
it gets voultage. I dont want to use chips that count automaticlly.

I will be Thankful for help,

Sarel.

All coins will not be the same in size. To differenciate between coins what you have thought about? What happens if some one drops a opaque circular piece of carboard in the size of a coin?

With the condition of no counters, then you would probably need to go with FF setup as counters. The easiest way to start is to generate a state-chart to model the behavior then use FFs to realize the State-machine.

As far as detecting the different coins, most likely the problem is not to detect different coins, but to realize the circuit of a counter without actual counters.

Otherwise the size of coins and weight can be differentiated with mechanics and you don't need any fancy electronics. Think of a coin sorter and all you need to do is count the coins falling down the individual tubes.

Since this is a school project I would have you look at implementing a state-machine via Flip-Flops. Circuits are easy to come-by, but the real value, (and job market skills) come from learning how to solve it yourself. Let me know if you need any more advice.

Red

Well, You know what you are talking about
That what I gonna use.
Thank you.

@Paranam- anything with a coin shape will be ok, Its only the idea.