Where can I get LCDs that are used in calculators/watches?

[Mahkoe]

Hi all! I'm in the "buying parts" phase of my latest project, which is a microcontroller-based calculator watch. I'd like it to last at least a few years on a normal coin cell battery. Furthermore, the microcontroller I've chosen can run an RTC and an on-chip LCD driver for the low low cost of 1.4 µA (this amounts to over 10 years of life on a CR2032 coin cell!)

Obviously I would want a very small 7-segment LCD, with at least 8 digits to work with. This is screaming "hack an LCD out of a cheap calculator!", except that if I eventually wanted to make more, I would have to go through an awkward calculator disassembly each time. Definitely not ideal if I wanted to make this into a product and sell a few on my website.

So I was wondering if anyone knew any sources for cheap, small LCDs, without the driver boards.

Thanks

 

[Colin Mitchell]

Buy $2.00 scientific calculators from the $2.00 shop.

 

[chopnhack]

I would try E-Bay for that particular part, E-Bay is a portal to the factories in China, of course you have to beware of counterfeit parts, etc. but for pricing, they are hard to beat.

As for 10 years on a CR2032, I don't think so, theoretically yes, but in practice I doubt the battery will keep sufficient charge over that time period under load. Most batteries have an internal resistance of 10-40,000 MΩ so there will be a natural discharge over time. I would also assume the chemical reaction would reach equilibrium at some point.