A wallet alarm : Suggestions pl

[NewPie]

Hello all,
I am sort of new to electronics. I am software developer with an interest in tinkering. Recently I learnt about fab labs and have access to one. I need to propose a project idea before they would let me use the fablab. I have thought of product I really want.
I would like a credit card shaped alarm clock that would go in my wallet.

My question is about the battery. Could you suggest what sort of battery I should consider.

a) A simple button cell battery. As these are easy to find. However, they may be too fat. I would need something that is 'almost' as flat as a credit card.

(And hopefully no health hazards keeping it inside the wallet?)

b) Some ultra thin ones like these -
https://www.bluesparktechnologies.com/index.php/products-and-services

https://www.powerstream.com/thin-lithium-ion.htm

However, seems an overkill. I would prefer a low cost solution. I don't need a battery to be measured in microns.

c) Some here -
https://www.alibaba.com/showroom/thin-film-battery.html


Any inputs please let me know.
Best
NP

 

[alec_t]

Welcome to ETO.
Nice project, but there'll be quite a few hurdles to overcome. Have you searched for ultra-thin displays too?

 

[NewPie]

Thank you. I am planning to have just two circular dials. One circle for time and the other for alarm. One single light source on the circle to tell the time. I would like to avoid displays. There are things I need to figure out. I feel if I know the battery rest will be ok?

 

[alec_t]

One single light source on the circle to tell the time.

Can you explain how 1 light indicates time?

 

[audioguru]

Can you explain how 1 light indicates time?

A circle of 12 or 24 LEDs and only one is lighted to show the hour hand of a clock.

An alarm clock is supposed to be heard. But it probably will not be heard in a wallet in a pocket.

 

[NewPie]

Hello alec, audioguru
Yes. I am simply having one LED light up to show the hour hand. A half hour resolution is enough (5,5:30,6 etc ). Depending on the size of the LEDs I may need a big circle. Even if I have a reasonably proposal thats enough. The alarm should be heard. If needed you might take the card and keep it beside you or in your shirt pocket.

 

[audioguru]

The sounder can be the piezo transducer used in a greetings card.

 

[throbscottle]

Even a single led will drain a battery that small more quickly than you would like. Your alibaba link is for shrink wrap films for standard batteries - not what you want! I reckon, if you can get around the battery problem, you could equip your card with a connector so you can connect a wire from it to your pc and set the alarm time that way. If you absolutely must have a display, it would be better to have a button you can press to view, like the old led watches did, or go for an lcd.

For reference, I have a calculator which is a little thicker than a credit card - probably if you measured the card including the embossed writing would be it, came free with a bank account. Has clickey buttons and lcd, a solar panel for power.

Hope this is of some use. Good luck

 

[audioguru]

Some cheap calculators have a photo of a solar panel on it instead of a real solar panel.

 

[throbscottle]

So if they have a photo of a solar panel and also don't have a battery, do people who have them notice they don't work???? Could be missing a trick here!

 

[audioguru]

I have a "Dual Powered Solar-Battery" calculator in my hand. I think it costs $2.00 (a little more than 1 quid) and has a disposable coin cell silver-oxide battery that lasts about 10 years. This calculator has a photo of a solar panel on it.

A tiny solar panel needs a lot of light to power a calculator. Artificial light in the evening and at night on the solar panel of a real dual powered calculator is not enough to make the screen work so they have a battery.

When I was in high school I used my brain or a slide rule, not a calculator. They do not have a solar panel nor a battery.
My first calculator uses a red LED panel for its display. It eats 9V batteries and it still works.

 

[throbscottle]

Should I stick a photo of a solar panel on my forehead? Will people who use my brain notice if it doesn't work? Oh wait...

 

[audioguru]

Should I stick a photo of a solar panel on my forehead? Will people who use my brain notice if it doesn't work? Oh wait...

Do you have just a photo of your brain inside your head?

 

[throbscottle]

That leads to such a convoluted line of thought my poor old brain just can't get round it. Obviously must be a photo then. Wonder where I put the original?...

I wonder if you stuck a convincing photo of a solar panel on a slide rule (or for that matter, a real solar panel), how many people you could fool that it was "solar powered"????

This really isn't helping the OP though. Probably gone off thinking we're all mad.