need help building a coin sorting machine

[pcgui2001]

hi guys, i was wondering if any of you guys can give me some help on how to build a simple coin sorting machine? this is a project for digital electronics class so obviously it would be cool if i could make it count the money and give u a total as u insert the coins. i know it would be simpler to make it just count the number of coins that have gone through it but counting the amount in currency would be more impressive. anyway i really have no clue how or where to start so i would appreciate a little help(or a lot of help )

i guess a start would be to get a schematic diagram.
well thanks guys and i hope to hear from you real soon

 

[Nigel Goodwin]

I don't see any electronic problems at all, and a circuit isn't likely to help you - all the problems are going to be mechanical - you need someway to sort the coins and arrange a different signal from each value of coin. Usually in coin selection mechanisms (as in vending machines etc.) the coin simply hits a micro-switch as it falls - which switch it hits depends on the way the selection mechanism seperates the coins.

 

[Chilli]

Why not use a small coil (AirCoil) in the path the coin slides?

Somehow like a "metal Detector". Every coin will give a different signature
which you can then use to drive different counters.

Just a thought.

 

[Electric Rain]

What you need is a coin validator. (Unless you want to make the validator itself, then... good luck with THAT. :lol: ) That's where you should start.

The easiest way to count the money is by using a PIC. Therefore, another thing you should look into is learning PIC programming and buying a programmer. :wink:

 

[MrMikey83]

I have a coin counter bank I bought at the mall. It doesn't actually sort the coins, but it does count an amount of what you've put into it.
When you insert a coin, you push it through a set of rollers. As you press it in, one roller moves over widening the space as the coin goes through. On the inside, the roller hits different switches. Depending on how far the roller is moved (diameter of coin), contacts are closed and the coins amount is added in the circuitry and displayed on an LCD.
I dont have a schematic, but maybe this description will help with a design.

I have seen some mechancal type sorters that have a rotating disk. The coins are put into a funnel at the top and one at a time, the coins go into a notch in the disk. The disk spins and below it are 4 holes. First is dime, then penny, then nickle, then quarter. If the coin is a quarter, it passes over the first three holes because they are too small.
Other sorters Ive seen go by a coins weight and as each coin rolls through, different tilting platforms let the coin fall off the right side and into containers.

Hope this helps...
~Mike

 

[pcgui2001]

while this doesnt nessesarily(spell check) make things easier foe me bc i still have no clue how to build the circuit..... maybe it will be easier for u guys to help me out..

what its going to do is....its going to have 4 slots, one for each coin. so i wont need a sorter. anyway each slot is going to have a lever switch which will get activated when the coin falls on it. every coin u insert gets added up to the amount on the dual 7 segment displays. so this means ill need adders right?? if so how many? and is there an IC that is already an adder?

im just looking for that info that will be able to get me started. anyway hope this helps u to help me

Thanks guys

 

[Optikon]

while this doesnt nessesarily(spell check) make things easier foe me bc i still have no clue how to build the circuit..... maybe it will be easier for u guys to help me out..

what its going to do is....its going to have 4 slots, one for each coin. so i wont need a sorter. anyway each slot is going to have a lever switch which will get activated when the coin falls on it. every coin u insert gets added up to the amount on the dual 7 segment displays. so this means ill need adders right?? if so how many? and is there an IC that is already an adder?

im just looking for that info that will be able to get me started. anyway hope this helps u to help me

Thanks guys

Thats good - avoid the sorting problem. While it would be great to do all the mechanical design on such a system, you must stay with what is practical for your electronics class. The real problem you would like to study is adding up the coin values. Since you will be using mechanical lever switches, you will need to add debouncing circuits to those.

My suggestion would be use a PIC and have some inputs:
25cents
10cents
5cents
1cent

The PIC will monitor these inputs and wehn it sees a transition on one of them, it means that corresponding lever has tripped indicating a coin of that value has been inserted(dont forget to debounce these or you'll get false counts). The PIC continually adds up input "counts" from your switches and outputs digital signals appropriate for driving the LED display.

If you do not want to use a PIC, you can build the same thing with logic gates, build binary counter circuits for counting lever clicks and then run all the counter outputs into an adder. You can also interface BCD to LED driver circuits to run the 7 segment displays. Make the whole thing synchronous - you'll need a clock and put flip-flops at the output of counters & adders.

 

[pcgui2001]

i wont be able to use a PIC bc it requires programming that i dont know of or that hasnt been discussed in class. so i guess i will have to stick with adders and gates and counters or whatever else that is needed

Ill keep u guys posted