DIY Forum


Ultimate HandymanUltimate Handyman on Pinterest


DIY Forum/Home improvement advice forum




It is currently Fri Apr 26, 2019 5:12 am

Time zone: Europe/London [ DST ]



Post new topic Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Wed Oct 17, 2012 8:42 pm 
Newly registered Member

Joined: Wed Oct 17, 2012 8:38 pm
Posts: 1
Has thanked: 0 times
Been thanked: 0 times

in my school we are setting up an enterprize, which will produce kinetic phone chargers and sell them.

The idea is that in a wooden box we'd fix a bearing with a magnet on it and put wound up magnet wire around it, the two terminals then would go to a 3.7V battery, then through a LED, a 5v voltage regulator, and into a usb cable which could charge phones.

Could you please explain which wire of the solenoid would be positive and which negative, how should it all be set up, im probably missing a lot of resistors or capacitors.

I found out that one should use a diode bridge and a smoothing capacity, but im lost on what to put inbetween the capacitor and the battery to charge it up.

Id be greatful if you kept it simple, thank you.

Share on FacebookShare on TwitterShare on DiggShare on Delicious
Reply with quote  
PostPosted: Wed Oct 17, 2012 9:04 pm 
Senior Member
User avatar

Joined: Mon Mar 15, 2010 11:49 pm
Posts: 10338
Location: Oban
Has thanked: 349 times
Been thanked: 1829 times
You can't get 5V out from a 3.7V battery unless you use some form of switched mode power conversion technique - nor will a 5V regulator work with less than 7V going into it.

The output from the 'generator' depends on many factors, turns-ratio, magnetic flux density, number of poles, rotational speed, air gap ad-infinitum.

The solenoid (generator) output will be 'alternating' but the bridge rectifier sorts the polarity to the capacitor.

You need to do a bit more research or provide more technical information if you want help from us.

sent from my laptop using my fingers - because we REALLY need to know where it's come from.....

Reply with quote  
PostPosted: Wed Oct 17, 2012 9:09 pm 
Pro Carpenter
User avatar

Joined: Sat Dec 16, 2006 10:11 pm
Posts: 21099
Location: redhill surrey an auld reekie laddie
Has thanked: 709 times
Been thanked: 2041 times
anything you sell will probably need a ce mark and comply with various regulations :dunno:

we are all ------------------still learning

Reply with quote  
PostPosted: Wed Oct 17, 2012 10:07 pm 
Senior Member

Joined: Sat Sep 01, 2012 7:03 pm
Posts: 8622
Has thanked: 41 times
Been thanked: 1470 times
How can I put this in simple terms? :scratch:

:cb Got it. Its a complete waste of time.

I shall expand on that:

You are attempting to make a phone charger that works by a magnet moving in / near a coil. So why does it need a battery?
Also as Kellys_Eye said, you would need to do some calculations as to the size of coil, the size of magnet to get enough voltage to charge a phone. By making a coil of wire and running a magnet through it will prove the principal works, but it wont give you any figures from the start, it will if you go for trial and error. Also you will find out about the coil, which wire is positive, and which wire is negative. (Try it and see, now figure why you get the answer you do)

You may want to try this, borrow some ones push bike that has a dynamo and lights fitted, turn the back wheel, does the light come on? (try it and see) Will this charge a phone?

A well known DIY store used to sell a torch, just like you are planning, they don't anymore, figure out why.

Let me ask you this: Assume you made it, and it works, how will it move? That means you would (well the person that has it) has to stand there shaking it. Human nature will say take the easy option, plug in a phone charger.

I would suggest, you do more research, not into what you can make but what people will buy.
In life, some people will set up a shop selling what THEY want. They soon close down due to lack of business, the reason is because they sell what THEY want, not what the people near the shop need.

Print this out and take it into class, and say some one said.....................

Fret not, a forum is a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link to find out more.

Working on anything electrical? have you got a multi meter? why not? Would you hit a nail with a shoe?

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here

Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 



Similar topics

Time zone: Europe/London [ DST ]

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Visit Solent plastics




News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list
ultimatehandyman privacy policy



Powered by phpBB® Forum Software © phpBB Group