Looking to build mini pen light version of this flashlight:

[fsir]

I'm a very rusty ex-electronics worker. I really don't remember much.

I'm unclear on what values I should use or on all the parts I need.

I want this to be a small, mini pen light version with a weighted lanyard acting as the twirling mechanism.
The same half sized, single aaa pen lights you see on eBay.

I can surmise I will probably need a micro electro motor at one end, a micro rechargeable battery in the middle, an LED at the other end and a switch. However, I'm not sure of what values or what additional components I'll need, like diodes or resistors, if any or what types (shapes) to get for the most stable connections. As this will be a mini flashlight that charges by twirling the lanyard, I don't want any connections that can shake or rock loose, obviously.

I know I'm looking for basic function on/off...no bells or whistles.

Can anyone give me an idea of the components and their values I could get to build this?

Basically, I'm looking to build this as an ultra small and portable survival light. Thanks for any advice.

I'll be glad to answer any questions if my description has been unsatisfactory but I'm open to any improvisations.

 

[fsir]

Just in case anyone is unsure of what values to recommend, my plan is to use a 3 volt led, 3 volt rechargable battery and 3 volt micro motor.

Does that sound safe or do I need to raise or lower any of the values?

Thanks!

 

[Audioguru]

Nobody makes a 3V LED. They are anywhere from 2.8V to 3.6V and you get whatever you get.
Nobody makes a "3V rechargeable battery" but one Lithium cell is 3V when dead and is 4.2V when fully charged.

I have never seen an ebay lanyard light but I think it will be very dim and the lighting will not last long.

 

[fsir]

Nobody makes a 3V LED. They are anywhere from 2.8V to 3.6V and you get whatever you get.
Nobody makes a "3V rechargeable battery" but one Lithium cell is 3V when dead and is 4.2V when fully charged.

I have never seen an ebay lanyard light but I think it will be very dim and the lighting will not last long.

Uh oh, that doesn't sound too promising for my project.

I do have larger hand crank flashlights, however, and those do work well and are plenty bright.

Of course, a hand crank dynamo flashlight is not exactly the same as a twirl charge flashlight.

Thanks the reply and the info...

 

[fsir]

?..but I think it will be very dim and the lighting will not last long.

Why is that, by the way?

Is it because the micro motor can't charge the battery fast enough being turned by hand?

I mean, if you could charge the battery by hand so the battery is full, why wouldn't the light last as long and be as bright as any other pen light that uses the same battery?

Im not looking for the light to last days on one charge, just enough to get someone through the night in a survival situation.

 

[Audioguru]

By twirling a lanyard, how does the motor generator in the flashlight spin? Do the magnets in the motor keep it pointing to the North Pole of earth? Then the motor will spin very slowly and generate almost nothing.
How many hours of spinning allows the LED to light for a few minutes?

 

[fsir]

By twirling a lanyard, how does the motor generator in the flashlight spin? Do the magnets in the motor keep it pointing to the North Pole of earth? Then the motor will spin very slowly and generate almost nothing.
How many hours of spinning allows the LED to light for a few minutes?

Thanks for your reply again.

I'm pretty sure electro motors produce electricity because they contain coils that when moved around a magnet of some kind inside the motor produce magnetic induction, which results in electricity.

If you look on YouTube, you should find examples where people are testing mini motors by twirling the rotor with their fingers while it's connected to an LED, which consequently lights up.

 

[fsir]

This is not a micro motor but check out this video to see what I mean:

You see how he spins the motor and the lights go on?

Well, I just want to spin a micro motor to charge a small battery to run an LED light.