Introduction: Human Powered Phone Charger

Picture of Human Powered Phone Charger

Mobile phones / Tablets have become an integral part of our life. One big hustle which every mobile user faces is charging the device. Well if you have a power source like AC wall supply or batteries lying around then it is easy but what if you are stuck in a place where there is no power source, like for few days?

I got this idea when a cyclone struck my area and we had no power in the whole city for like 10 days. The phone towers started working from the 2nd day itself but since our smart phone's charging doesn't last more than a day or two, it was of no use. That's when I realised how dependent we are on electricity provided by power stations.

This project will help your phone stay alive in those kind of situations. Remember, my objective is to make a charger with parts which will easily be available.

Step 1: Designing

Picture of Designing

What we don't want to use: Batteries, AC household power

What we want to use: Muscle Power (Mechanical Energy)

Solution : DC Motor/Dynamo

I'll be using a DC motor in this tutorial since it is more easily available than a dynamo. Well technically a DC motor is also a DC generator so when you apply mechanical energy to a DC motor (rotate it's shaft), it produces some amount of power.

But we have another problem. Depending on the speed at which we rotate the shaft, the voltage across the terminals vary and we don't want anything above +5 volts for our USB charging. So we need a regulator block which would take in the variable power from the motor and convert it into DC +5V

Option 1: Linear Voltage Regulators (Like 7805)

This itself does the job but linear regulators have a very low efficiency. This is because here if the load draws 'X' amps of current then even the input needs to provide the same 'X' amps of current.

Power wasted = (Input voltage - Output voltage) * Current drawn by load

We would be wasting more than half of the power we generate through the motor and hence not advisable. Well if you are in a hurry and have no other option then go for this.

I realised this after reading the Instructable "Solar Powered Heart Rate Monitor" written by Dangerous Tim. Thanks to him.

If you want to use this option, then head to my first version of this project which I published on EngineersGarage.com (DIY- Emergency Phone Charger using a DC Motor)

Option 2 : Switching Voltage Regulators (LM2576/LM2596 5V version)

Switching regulators are more efficient since they turn on/off the input at high speed (Pulse Width Modulation) to bring down the voltage at output and waste less power in form of heat. They require few external components but totally worth the complexity.

To make things more easier, I'm using a ready-made switching regulator based power supply module which is easily available. But since they are only adjustable versions available, we need to first set the potentiometer present on it such that it gives output close to +5V

-Use an external DC power supply (Battery or adapter) which can give more than +7 Volts to power up the module.

-Connect the multimeter in voltmeter mode to the output of the module and start adjusting the potentiometer using a screw driver until you see a value very close to 5 Volts (5.0 to 5.1)

Step 2: What We Require:

Picture of What We Require:

Components:

  1. 12V DC Geared Motor
  2. LM2596 (or any equivalent) IC based Power Supply module
  3. 1N4007 Diode
  4. Female USB connector
  5. A Wheel
  6. Wires
  7. Motor Clamp/ Chassis

Tools Required:

  1. Screw Driver
  2. Multimeter
  3. Soldering Kit
  4. Scissors

Note: If you want to build the power supply module on your own, refer the schematics in the next step. Or else you can skip the next step :)

Step 3: Schematics

Picture of Schematics

- The motor I used is 100 RPM. I chose it because the ones with lesser RPM than this required more force to turn and the ones with higher RPM although easy to spin, had to be rotated at high speed to generate same power.

Step 4: Fix the Motor:

Picture of Fix the Motor:

Attach the motor to the clamp/chassis and then attach them to a firm place like on top of a table or something. This is to ensure that the motor doesn't move away when you start rotating it.

Step 5: Put a Hole Into the Wheel Away From the Center

Picture of Put a Hole Into the Wheel Away From the Center

Heat the screw driver (make sure you don't burn your hand) using a candle or any other fire source and punch a hole into the wheel, away from it's center. The hole should be big enough for the screw driver to slide in and out smoothly but not too big.

Step 6: Fix the Wheel to the Motor's Shaft Using the Screw Given Along With It

Picture of Fix the Wheel to the Motor's Shaft Using the Screw Given Along With It

Step 7: Connect Motor to Power Supply Module

Picture of Connect Motor to Power Supply Module

Connect one wire from the motor to the negative terminal of the module and other wire to the positive of the module through the diode. The diode is used to protect everything from reverse current. If you spin the motor in wrong direction, it acts as open circuit and doesn't let the reverse current to pass.

Step 8: Soldering the USB Connector

Picture of Soldering the USB Connector

Solder the USB female connector onto a small GPCB.

- Apart from the 4 terminals of USB, you will also find two V-shaped leads on the connector. These won't normally fit in the PCB and hence you need to enlarge them using the tip of scissors. Just insert the tip of scissor in the hole and start rotating it, pushing it into the PCB. Do this until the hole widens enough.

- Once the holes are wide enough, attach the USB connector to the PCB and bend the V-shaped leads towards each other. This would let the connector to hold onto the PCB tightly.

- Solder the +5V and GND terminals of connector onto the PCB(You need not solder the data lines but soldering them would make the connector stay firm ) . Then solder a male header near to it and link them.

Step 9: Testing and Adjusting

Picture of Testing and Adjusting

-Connect two female jumper wires, i.e. for the +5V and ground terminals and attach them to the output terminal of the power supply.
*****Polarity is very important. Make sure you don't mix up the +5V and GND lines.*****

- Hook up the multimeter(in voltmeter mode) to the input of the power supply module.

- Insert the screw driver into the wheel's hole and start spinning the motor at a nominal speed in one direction say clockwise. If the meter's reading starts going up, then this is the correct direction to spin. If there is no change in the reading then the reverse (i.e. anti-clockwise) direction is the correct one.

Also make sure you spin with enough speed such that it at least shows 8V in the multimeter.

- Now hook up the multimeter to the output of the USB connector (Red probe to +5V pin and Black probe to GND pin) and start spinning once again.

- You need to check two things now:

1) Sign: If there is no sign, then it means the polarity is correct and if there is negative sign then reverse the USB connection coming from the power supply.

2) Voltage level: The level should be in between 4.8 to 5V. If it is not in this range then adjust the potentiometer present on the power supply module using a screw driver.

Step 10: Implementation and Improvements Suggestion

Picture of Implementation and Improvements Suggestion

Now connect your Phone/ Tablet to the USB port using a cable and let your muscles do the rest of the work!

***EDIT***

Since many people asked, I tried looking for the output current. I used this battery monitor widget to check the current and found out that at the system is capable of delivering 550mA current to the phone.

Points to be noted:

  1. Switch off the device while charging. This will let it charge faster.
  2. It does take a lot of time to charge so don't expect it to charge your device from 0% to 100%

Improvements:

1. You can attach the above setup to the bottom part of a manual sewing machine. Then you would be able to rotate the motor shaft for longer time with lesser effort.

(Sewing machine image from google images)

2. You can attach it to a bicycle's wheel. Because it is healthy to ride a cycle, saves fuel and now it will charge your phone for free :D

P.S. I've written few project tutorials before (you can checkout them in my website) but this is my first time on Instructables. So apologies in advance if the Instructable is not organised properly. Please leave your suggestions as comments which would help me improve the quality.

Hope you liked it! :D

***Edit***

Bottom part of a manual sewing machine is called a "Treadle"(Exact word added from comments. Thanks to thatto, diamonddozen)

Comments

Ganesh Selvaraj (author)2015-01-28

The project got featured in hackaday.com too !!! :D :D

http://hackaday.com/2015/01/27/diy-phone-charger-born-from-cyclone-disaster/

awesome bro

aliyavar (author)Ganesh Selvaraj2015-10-26

hey Ganesh

Great job bro.

can i have ur email id and other contact details so that we can talk more on this?

Ganesh Selvaraj (author)aliyavar2015-10-29

mail me at ganesh@robotsreloaded.com

Bolmik (author)2017-08-21

I think the back emf may destroy the motor

FickryM1 (author)2016-06-16

Nyoba akhhh

geekster88 (author)2016-04-22

This is awesome! Just at tip: some people in the comments would really like a specific motor off of Amazon or something (personally, I understand that it's just a DC motor) as some feel a bit lost it seems. Keep up the great work!

sitenP (author)2016-04-02

awesome sir...

LeanneFischler made it! (author)2016-03-31

Great tutorial - it took me a while but got one working pretty well!
I used the simple linear regulator and it charges a bluetooth speaker, providing up to of 1.3amps as well.

Next step is to get it charging an iPhone... any tips on this?

Thanks!

Parv rocks (author)2016-02-22

Great idea sir!

Thanks a lot

Akin Yildiz made it! (author)2016-02-11

this is great, i just posted a similar project and saw yours.!!
www.instructables.com/id/Bicycle-USB-Output/

goldend2 (author)2015-10-31

how much is the output current of LM2596 power supply module???, BTW in your first version how much watts does your 330 ohms resistor?

ashu cool (author)2015-10-19

from where to get lm2596 ic based power supply module

You can get it from online stores like ebay

piedrabob78 (author)2015-10-22

Hello, one question. Why are you using a 12v motor instead of a smaller one? I am kind of new in this so i will appreciate any help. Thank you

The motor you use is of your wish. You can use any kind of DC motor and the output will vary according to the motor's specifications

ashu cool (author)2015-10-19

great project sir

sh117 (author)2015-10-16

it is awesome but it does not work for moto and Samsung phones alones but it works for other phones like lenovo,lg,micromax,iball,xolo

shomas (author)2015-10-07

Thank you for this project.
one thing I'd add is three 2.7v super capacitors just after the blocking diode hooked in series with each other and in parallel with the remainer of the circuit, along with 3 1k ohm resisters forming a voltage divider network to keep the capacitors ballanced. Adding this to the circuit will temporarily store extra power and prevent and prevent the short brownouts as your spinning the motor fluctuates.

rajat_mishra_23 (author)2015-10-04

Sir i want to ask the rating of the diode D2 in the schematic digram of power module

greenasgrass (author)2015-08-31

Hello, I'm a newbie. I've done everything you have done, and have a constant +5v coming out of my regulator to my USB. Phone won't charge? Any ideas? I've tried multiple phones, and charger lead itself is in working order. School project

dudes (author)greenasgrass2015-09-17

Make sure the + and - outputs are connected correctly to the usb port, if they're backwards it won't charge (obviously). Does the phone react at all? For example, does it give a warning or some sort and reject the charger? Or does it do nothing at all? If it does nothing, double check all connections and the usb cable.

fvarickanickal (author)2015-09-06

sir, plase clarify about the motor

rweerstra (author)2015-09-01

Sir, I purchased the following motor, 12v DC 100rpm High torque gear box electric motor 25mm from Amazon by Amico. Because of the gearbox, I cannot rotate the shaft even with pliers. If I remove the gearbox, I can rotate it but I only get about 1.5 volts on the connector with no load. Do I need further specifications for the motor or can you give a suggested part number for reference before I purchase another moter that doesn't seem to work? Thanks.

alexanderreybo (author)2015-06-14

hello im from iran and i can,t sperak well

how do it work?

PrinceT1 (author)alexanderreybo2015-08-21

Its one of the simplest circuit, you need a motor, thats it

DaniyalA1 (author)2015-08-03

I tried every diy speaker design on the internet but all of them including this one, produce little sound. I guess I'll have to connect an amplifier but the problem is I am only 15 so i can't get the resources to make or buy one.

ayushi4986 (author)2015-07-04

i am a student of class 12 actualy we have got a project to make a working model and i am highly impressed by this working model.. if you could help me out a bit more ill b highly obliged

DebashishM (author)2015-03-22

Really nice and clever idea. Only thing is the person using it need to be very patient to get it charging his phone.

Sornakanth (author)2015-02-18

Will 1000 rpm motor suits this experiment

MarkP11 (author)2015-02-09

How about making two or three up and selling them. I don't have the time or resources to do it.

Tyler2468 (author)2015-02-08

I am using a Hossen 12 V 120 RPM High Torque DC Gear box motor replacement motor along with all other exact components you have mentioned. I am easily getting the expected/required 5 Volts to charge my iPhone 5. The problem is that I am only between 50mA - 100mA which is not adequate to charge a phone. With all other things equal, could this be a problem with the motor perhaps? Any suggestions?

danielcortez (author)2015-02-05

Hello sir, can I use this (2-5V to 5V
1.2A DC-DCConverterStep
Up BoostModuleUSB Charger) instead of the


  1. LM2596 IC based Power Supply module. pls reply immediately .tnx
shubhamtrivedi95 (author)2015-01-29

project is awesome. but my question is that to charge any mobile handset properly the circuit should produce 0.55A current. so can we solve this problem?

shubamtrivedi95, Ganesh said it produces approx 550mA...that converts to 0.55A.

zorrothefox (author)2015-01-30

Hi,

As I mentioned in my last comment, awesome project!

I was taking a look at this 12V, 100 rpm, geared motor here http://www.amazon.in/Johnson-Geared-Motor-gear-rob...

The product details mentions a no-load current of ~800mA, and a load current of ~9A! In this case, what'd be the output current from this motor? Would it be higher than the motor mentioned by you?

Please let me know

zorrothefox (author)2015-01-30

wow... serendipity... I just found a 24V DC Motor with gear assembly a few days ago. Was wondering how to build a mobile charger or LED flashlight from this. Your project is a perfect match.

Thanks for taking the trouble!

asgers1 (author)2015-01-30

Chouldn' you use a diode bridge and make it work no matter what way you spind the whell?

Zachatt66 (author)2015-01-29

if i were to wrap a copper wire instead of using brushes around a dc motor commutator would i still be able to get electricity if i just spin the magnets around the motor?

MaDoGK (author)2015-01-29

Cool! Saved to make later! Very easy to understand! :)

Ganesh Selvaraj (author)MaDoGK2015-01-29

Thank you for the feedback :)

RajatSharma1906 (author)2015-01-29

Very interesting. Where dis you find the

Switching Voltage Regulators (LM2576/LM2596 5V version) ?

Bienvenido Santos lll (author)2015-01-28

how to make Lm 2596??

LM256 is an IC, you cannot make it. If you are referring to the power supply module, then follow the schematics in step 3 :)

thereyno (author)2015-01-25

Very nice project! Can you tell me what is the module that you use? Is that a , some kind of arduino? ^_^

Ganesh Selvaraj (author)thereyno2015-01-25

Thank you thereyno. It is a voltage regulator module. Nothing close to an arduino. It 'Regulates' the voltage supplied to it. In my case, it converts the unregulated input which is around 9V-14V into a regulated 5V output.

thereyno (author)Ganesh Selvaraj2015-01-28

^_^ ty for that.. the output of the charger is constant? the current and the voltage??

Ganesh Selvaraj (author)thereyno2015-01-28

Voltage is constant (You can adjust it using the potentiometer). Max. Current depends on the speed at which the motor is being rotated at.

par64guy (author)2015-01-28

For the circuit, I would recommend replacing the diode with a bridge rectifier. That would then allow you to charge no matter which direction you spin the motor.

Ganesh Selvaraj (author)par64guy2015-01-28

Yes it can be added. But the point is that once you start rotating in a particular direction, the other two diodes would be of no use and also you would waste energy on two diodes instead of one. If the motor was giving an AC output then the bridge is mandatory since no matter which direction you turn, all the 4 diodes would be required (2 for each half cycle)

About This Instructable

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Bio: An electronics engineer who loves making projects related to Electronics, Embedded system and Robotics.
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