Digital counter project

[Inventor]

Hello there!
Good to find this forum. I am very far from any engineering as a graphics designer but I am interested to start a project and I have few questions related to engineering and electronics. I am curious how could this idea of mine be built? I would be very thankful for any help. The idea is to make a gadget - a digital counter.

Project: a digital counter part of it looks like a general safety pin. There is a digital screen attached to it. It has to be as light as possible. Screen should display around 4 digit numbers, they should be large enough to read easy tho. Every time the pin is closed the counter will display the counted number. Reset should be possible and taking back steps.

The questions are: how small can be a digital display? The best power solution? Maybe a mechanical version (some wheels to display and scroll numbers) of this counter would be cheaper to build? Is it true, the smaller digital gadget the more expensive it is?

I am very excited to hear your comments.
Thanks in advance!

 

[BobK]

I assume you are doing a study on how many diaper changes a baby requires

An LCD numeric display can be very small and light and uses very little power. It would not even be a stretch to make this 1" across. Think of the little stick on clocks that are about that size. Are you thinking smaller than that?

I would do it using a microcontroller, but discrete logic could also work, though it would likely be larger.

Bob

Edited: Welcome to the forum!

 

[Inventor]

Hahaha BobK!
Nice one about the diapers! Close, but not
And thanks, nice to meet you. I hope to stay around for a while.

About the size, well the whole system should fit and weight the same as common dice and then the pin is attached to it.

 

[BobK]

That is going to be challenging. I cannot find any 4 digit displays that are less than about 2 inches wide from mouser or digikey. And LCD numeric displays are not easy to deal with, they have a lead for each segment (32 for 4 digits), and need to driven by an AC signal. I take back my initial reponse.

Bob

 

[Sid723]

I remember way back when LCD clocks were becoming the rage. You could buy a cheap small one with a magnetic backing that you can put on your refrigerator.

If you can get one of those old ones, maybe you can hack into it and take the display out. There are also PIC micros that come in 8 or even 6 pin surface mount packages that you can program to drive the LCD as a counter. That would be small.

Only problem is, it is very difficult and you would need to know how to drive the LCD with the PIC. Lotta work, but it would be small.

 

[BobK]

I remember way back when LCD clocks were becoming the rage. You could buy a cheap small one with a magnetic backing that you can put on your refrigerator.

If you can get one of those old ones, maybe you can hack into it and take the display out. There are also PIC micros that come in 8 or even 6 pin surface mount packages that you can program to drive the LCD as a counter. That would be small.

Only problem is, it is very difficult and you would need to know how to drive the LCD with the PIC. Lotta work, but it would be small.

Yeah, I was thinking the same, but I suspect that the LCD's you would find are "bare glass" and the clock chip itself has all the segment driving logic. You would need a large (64-pin) PIC to drive all the segments without and additional driver chip.

Bob

 

[Inventor]

Hi guys,
I see that you had few ideas, but I have no idea what are you talking about. Any pic about the old magnetic lcd clock? Do you have any experience with the digital paper?
Could it be a display for me?