Hi
I want to make a mobile charger for my mobile phone
See my cell phone doesn't hold charge for too long
And it usually dies right when there is no charger available
And I'm in the middle of sending an important text
And everyone is waiting for my answer
And BAM it's gone
I have to wait for half an hour before I can get off this stupid bus and get into the office to realize they made a decision without me!
Again!
Now, there is actually a product out there which is basically a backup battery where you can plug your cell phone into it and charge it
You'll have to always keep this battery charged and carry it around with you at all times in case you need to use it
FOR GOD'S SAKE, IF I HAD THE DISCIPLINE TO CHARGE ANOTHER BATTERY AND CARRY IT AROUND WITH ME AT ALL TIMES,
I WOULD JUST KEEP MY CELL PHONE BATTERY CHARGED!
So, I decided to make my own handcranked battery charger
But I didn't want to make a product from scratch
So, I decided to use my handcrank flashlight
But I wanted to keep this one, so I went out to buy a new one
And soon realized that this thing has become a rarity around here
All I could find was this little piggy flashlight from Looney Store
But right when my daughter realized what I was gonna do to it she said
[Mehdi's Daughter] Dad? Why do you want to kill the thing
It still works good...
It's just a piece of junk!
[Throws piggy flashlight, laughter]
This thing is so low quality, I get to keep it*YAY!*
But I'm not gonna use it anyways
The little piggy won't be able to provide enough juice
So I open my good flashlight here
You can see there is a dynamo and the voltage it creates goes to the FULL BRIDGE RECTIFIER right here
And the voltage is later used to charge this tiny battery as well as powering the LEDs
This battery is 3.6 volts, having it on the circuit will limit the output voltage to charge a cell phone which needs 5.0 volts
So, I have to taken it out
*Desolders the battery*
I have the charger cable for my phone which I'll cut open
And then I simply connect the positive and negative lines to the outputs of the full bridge rectifier
The output voltage of the rectifier is not regulated
But I measured once that the cell phone requires somewhere between 300-500 milliamp of current for charging
And I don't expect this flashlight to be able to output that much current
So as soon as the cell phone draws the charging current,
the output voltage of the rectifier will be limited below 5 volts
So it kind of self regulates
Let's give it a try! *starts cranking*
There we go, the charger LED is on
Now it's off...
Turning much harder now *phone smokes*
OH NO NO NO NO NO NO!!
NO NO!
S**T! I killed the phone! F**K!
*Mehdi's wife enters* [Wife] Did you say you killed your phone?!
[Mehdi] No I...
[Wife] Did you? Damn it, Mehdi! How much do we have to pay for your f**kups!
[Mehdi] I was just making a video...
[Wife]All for your stupid videos and FOR WHAT? READ COMMENTS ALL DAY AND GIGGLE?
FIVE HUNDRED DOLLARS IS A LOT OF MONEY! WHO'S GONNA PAY FOR THAT? YOUR COMMENTS?
[Mehdi] It's probably nothing, I'll fix it myself
[Wife] Yeah, yeah, and its gonna end up in the pile of things-to-be-fixed
Don't you think I know your routine by now?
God! Why did I ever...
I made a horrible assumption
See, the cell phone started charging and drew current
But then, because the charging voltage wasn't stable enough, the cell phone disabled charging
And without any current from the charger, the stupid voltage jumped to something like 20 volts or higher
And fried the charging circuit short
*throws phone* I guess I'll fix that later
What I need is an efficient 5 volt regulator to add to the output of the bridge rectifier
which is nothing but a DC to DC switching regulator
Here is a typical circuit of a regulator
Fortunately, there are broken prototype boards at work I can cut a regulator from
Here we go!
Now I solder the regulator to my charger...
And it's done! Let's check the output voltage
See! A nice 5 volt regulated output
*Throws charge* Such an idiot, should have done it from the beginning
Since I don't have a phone anymore, I've borrowed an old iPhone from my beloved mother-in-law!
[Whispers] I'm going to try and charge this one
Now, I have to cut the charger cable again
And solder these to the output of my regulator...
Let's start cranking!
It's not charging...
AHH! WHAT'S WRONG?!
Apparently, with iPhones you also need to bias the USB datalines to somewhere around 2 volts. I just need some resistors.
I decided to cut a USB extension cord so that I can plug *anything* to my charger! Let's cut it
I solder the connector and the resistors to my regulator...
Now, we just shove in and hot glue everything in place
And voila! I have a flashlight with a USB charger.
Let's try to charge again!
Hey, hey, hey, hey! It's charging now!
[Whispers] Now, let's try my wife's new iPhone...
Let's try it out...
IT'S WORKING!
Can it charge a GoPro?
Let's try it...
Oh yeah, it charges everything! It's a universal flashlight and charger you can take camping with you!
I'm a genius, it only took me one cell phone and two charger cables to make this!
*laughter, then moans*
If you need your hands free to use your phone, you can use your kid!
Here you go! Crank away!
[Daughter] Why would you plug it here?
Hmm? NOOO! *blows cable*
[Mehdi Moans]