Instructables
(This instructable is for those who have basic knowledge of electric/electronics)

I found about a dozen used cell phone chargers very cheap from a local shop.

The cell phone chargers have faults in the plugs and cables only, the actual charger circuit were working perfect. I removed the cable and plugs and used these in many projects

In this instructable I will show you how I made a durable night lamp which will give service for many years.
 
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Step 1: Components Required

You will need.
1. A cell phone /Mobile Phone Charger with out put of 5 to 12 volts.
2. One white LED 5mm ( You can substitute with Blue color LED)
3. One resistance (for value click to see the chart)
4. One diffuser. I used a cap from an insulin syringe (BD), most white semi-transparent bottle caps do the job.

The diffuser is required to disperse the light uniformly in the room and make it cool to the eyes.

Step 2: Connecting components & finishing

1. Make a 5 mm whole near the voltage out put and connect the LED and Resistance as shown in the circuit diagram, observing the polarity of the current.

2. Test it by hooking to the mains power socket.

3. Finally glue the diffuser on it.

See an other view of the built up night light

Step 3: An other finalized night light

This is a picture with a different diffuser
iffee (author) 5 years ago
jsbarrie; every thing in the instructable is clear, if you need more clarification please let me know.
inshaajee iffee3 years ago
DEAR SIR.
my english Language is very bad .so i want some information for phone line power use .cane i write in urdu Language.

sir
main apna fone charge karskat hon? or keasy
orr phone line say zeyada sy zeyada ketny volt or amps hasal keaye ja sakty hen. mere requst ahy k app my email adresss py send kar den.
inshaajee@yahoo.com
god bless u
iffee (author)  inshaajee3 years ago
Now a days all telephone lines are digital working at 48 Volts DC.

Phone line on-Hook have 48 Volts and off hook between 5 to 10 volts.
Current 30mA to 40mA .

Battery charging is not recommended.
iffee (author) 5 years ago
Phoenixflame87; try with 100 ohm resistor
bilalinpk5 years ago
I have 5.7v and 800amp charger........ please tell me which resistance i can use, i will appreciate if someone tell me how i can calculate these types of calculations......
jsbarrie7 years ago
Hi- I want to make a bunch of LED room lights using old cell phone chargers. I would like to use several LED mounted on a reflector. I can design the reflector and attachments, I need help with the circuit diagrams for lets say 3 - 5 LEDs maybe more. My "clients" are people who have very low power and right now use kerosene for light. The LEDs using old cell chargers would be a big deal. I am designing both DC and AC versions of the light. Could you help with this? Any help is much appreciated.
iffee (author)  jsbarrie7 years ago
jsbarrie you can add more LEDs as per circuit taking into account total current / volts of mobile phone charger . Read original instructable for values and calculations. I estimate you can add 8 to 10 LEDs easily.
LED-P.JPG
bilalinpk iffee5 years ago
hello iffee........ please tell me how much voltage we have in our fixed PTCL wire....... and also mention amp
jsbarrie iffee7 years ago
Thanks! I'm going to build a version that produces the max lumens. I will photograph it and post when it is done. -jb
Eirinn5 years ago
Very very nice instructable - i am new in electronics and this helped me a lot!
I'm attempting this instructable with a 3.7V/340mA charger, and a 10-Ohm/1/2-Watt resistor, and it won't work correctly. My LED lights up and burns my hands after about 2 seconds, and goes out after about 30 seconds. What am I doing wrong?
iffee (author)  Phoenixflame876 years ago
Since charger is rated at 340ma and LED only consume 20ma, there seems that voltage on charger output are high. Try increasing resistor between 49 and 100 ohms and then measure voltage across the output of charger. Now recalculate the proper resistance. Note some chargers do not have fixed voltage output, it varies with the load. In your case 3.7volts are rated when the load is 340ma.
Would adding a capacitor in the line cause the light to slowly turn on and slowly turn off?
No. It's a little more complicated than that.
I would but the value would have to be fairly high as most SMPS power supplies are able to deliver a huge amount of power over a short duration especally during turn on which will charge a small capacitor really quickly, this would however also increse the turn off time. I guess it all comes down to what you call "slowly" (( you could always use a RC bridge which would give you the same turn on turn off times though ))
ateo6 years ago
Nice job, I have a lot of dead chargers. Greetings from a developing country of America..
cloner6 years ago
Will this burn my house if left unattended for a week?
jsbarrie7 years ago
Iftikhar- I will include your name on the paper I am writing. I will post some photos and some design ideas here soon. I am going to Guatemala to work on a universal LED circuit board that can be assembled in the field by local technicians. This way LED light is inexpensive. If made in bulk the circuit boards will be very inexpensive, maybe $.25 US each. I just got a lot of high output LEDs from China for $.19 each. The circuit board can hold 10 - 12 LEDs. I will post more soon. Thank you for your assistance. John
jsbarrie7 years ago
Hi- I want to make a bunch of LED room lights using old cell phone chargers. I would like to use several LED mounted on a reflector. I can design the reflector and attachments, I need help with the circuit diagrams for lets say 3 - 5 LEDs maybe more. My "clients" are people who have very low power and right now use kerosene for light. The LEDs using old cell chargers would be a big deal. I am designing both DC and AC versions of the light. Could you help with this? Any help is much appreciated.
iffee (author)  jsbarrie7 years ago
HI I am too from a developing country (Pakistan), I will be glad to help you in your project. You can post your question in the relevent Instructables. For your information I am retired person from the local Telecommunication Company. Iftikhar Ahmad
chrismake7 years ago
Ohh that's a great idea !! I just needed some night lamps for my pets in my garage. Thanks!! stonehenge360 -> Well you must not come out out of your "America" very often: these electrical outlets (type C) are pretty common throughout Europe, Africa, South America, Russia, Middle East etc... Basically, everywhere BUT America ;o)
iffee (author)  chrismake7 years ago
Yes, this instructable is from Pakistan so the outlets are of Asian type
haha im guessing ur not from America thats one freekin crazy electrical outlet u got there =)
trebuchet037 years ago
I gotta pull up the schematic... but you can drive a luxeon with a cell phone car charger too :D It involves some hacking, but its an easy way to drive one :D Nice work
Liganic7 years ago
Hey, very good idea using an old cell phone charger, I never thought of that! The second one with the other diffuser looks quite professional and clean, good work! Also very nice instructable.