Money box project for kids

[laserjetdog]

Hi
I am trying to encourage my kid to save money in a money box.
What I want to build is a money box and as the coin is entered it rolls down two differenrt shoots which as they pass different points an led will light and then go off or stay on as it completes its journey to the bottom of the box and then maybe sets off a buzzer when it hits the bottom.Maybe use up to 8 leds which can be seen as the coin makes its journey.
This has to be a simble circuit as i am a beginner to electronics

 

[BradtheRad]

I wonder if you are describing a pyramid shaped coin drop?

There's the matter of how a falling coin will trigger an led to light. Leaf switches would be convenient, but these are not easy to get a hold of.

There's the idea shown below. Springy metal or wire taps a nail when the coin falls on it.

- - - Updated - - -

Schematic of a simple version:

 

[laserjetdog]

Thanks for your help Brad.
Had not thought of using springy metal.Not sure how i could mount them but it sounds good.I had maybe planned to use 2 sheets of perspex with the guide for the coins in between them, with the coins rolling down and maybe hitting microswitches.Not sure if they will react or maybe jam coins.Thanks for the schematic it makes it clear.
Any help would be welcome.

 

[BradtheRad]

I have played with microswitches (with and without levers). They vary in the amount of pressure required to depress it. Some have a built-in lever which makes it easier to activate. It would be hit or miss whether you obtain the easy-to-depress kind, which would be triggered by a coin rolling over it.

In case you are interested in soldering, there are IC's which are inexpensive and easy to use. Examples:

555 (timer delay, oscillator)

4017 (rotates output through 10 pins)

3914 (10 led bargraph display)

Here is a crude conceptual diagram showing how a 555 and 3914 could light 9 led's in sequence. The tenth output would sound a buzzer.



Of course you could instead install 9 switches, so each coin would increase the volt level at the input of the 3914, causing the next led to light.

 

[laserjetdog]

I Would love to have a go at that circuit using 555 and 3914 chips.Had a look on the internet for pin outs.Would you mind labling the pin outs for
the diagram that you have shown as otherwise i am in the dark.
On the 3914 the led outputs are fine but not sure of rest of pins on 3914 and 555 in connection with your diagram.
Would 1 coin hitting the switch at the input to the 555 timer cause all 9 leds to light in sequence or just the no 1 led and the next coin no 2 led etc. on 3914.
This will be my last post on this.I dont want to take up any more of your time.Thanks again.

 

[BradtheRad]

Here is a prospective schematic of a 555 triggered by a coin touching a switch. The output does not come from pin 3 but taps off the rising charge on the timing capacitor. The scope trace shows how the signal rises. (The ground pin connection is not shown but is 'understood' to be attached.)



I'll find an image showing the pinouts, and another showing the 3914.

The signal must rise high enough to trigger all the 3914's led's. We'll see whether that will happen.

Another issue is the current draw during idle times. This must be minimized somehow, if you use battery power.

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Someone may be working on a similar project at this website:

https://www.electro-tech-online.com...eviews/12035-led-project-diagram-correct.html

 

[BradtheRad]

Webpage article about the 555 timer IC.

See the monostable configuration 2/3 of the way down.

http://www.kpsec.freeuk.com/555timer.htm

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3914 typical setup to light up led's in bargraph mode.

http://ecelab.com/circuit-volt-monitor-3914.htm

Pin 5 would be connected to the top of the capacitor at the 555 IC (pin 6 & 7).

It will require adjusting to get the desired time for all led's to light in sequence.

Instead of a 12V supply, you can try a 9V battery. If battery life is short due to high current drain, there should be a way to install some kind of solid-state turn on switch or relay.