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Led notification button using USB car charger Answered

Here an challenge that I am struggling. I do have understanding of how to put things together based on parts buying. Yet I do not have good idea of how to literally create from scratch. Hope someone can walk me through to create interesting concept. 

So I was wondering if can use USB car charger to power a led notification system with light on when button pressed and light off when let go the button. 

Specifics requested:

1. Button need to have ability to tolerate abuse and free from getting caught by any fabric or strings. 
Want this button  - http://www.parts-express.com/pe/showdetl.cfm?PartNumber=060-640
Avoid this button - http://www.parts-express.com/pe/showdetl.cfm?Partnumber=060-632

2. Any Led will do. Please give me options of two set of led. 

3. Power supply needed.  
Preferred USB car charger (charge my phone too) Similar to - http://www.amazon.com/Cigarette-Lighter-Adapter-Players-Charger/dp/B000CC6I5W
Any car charger will do if USB is too complicated. 
Try avoid battery at all cost. 

4. Step by step as how to wire the whole thing. Do not understand those schematic outlet unless actual pictures instruction. 

I have spent few hours on Google but just couldn't put puzzle together. So want to ask the community my burning question. Then I will be up for the challenge to really build it. I do have tools to build anything. Just need schematic step by step by genius like you. 

Then I will post WHY I asked this question. Thank you in advance. 



3 years ago

I am back! A project that was left on back burner for 3 years. Was successful with creation of DIY project but quickly found it was rendered useless during daytime due to wrong LED output. Its effective during night time.

So abandoned the project for time being... Now revisiting and entertaining light sensor to control light output during daytime and night time. Obviously brighter during day and dimmer during night.

Also want to replace "pen" with small 10 lm LED with COB LED strip. Yet COB LED can output 100-400 lm. Very bright for daytime but would be nice if I can figure out how to control dimmer module or something to reduce output from 100 Lm to 10-20 Lm or less.

BTW - Apparently I never replied thanks for those who contribute to my DIY and never shared the WHY I wanted to create it. Now will share WHY... I am deaf and always shutting my family with small kids around. Back then, my daughter was 3 years old, she would throw things at me to get my attention. Can be dangerous distraction during driving. So that how I came up the concept of giving her momentary switch button that she can push to get my attention. The LED is placed on my dashboard onto right side. Above the radio/CD. Many nights were successful using it but daytime... still had to throw food or something to get my attention. I am revisiting this project when I came across the idea of light sensor.

New Goal is to replace the following:

1. Single LED into Long COB Led flat light source: http://www.ledlightmake.com/cob-integrated-led-lig...

2. Add Light sensor to control light output: http://everlightamericas.com/ambient-light-sensors...

3. Replace momentary switch stick with new Velcro.

4. Find better wires that handle extreme cold weather near -30'F and thicker wire to prevent tangle up or stiffing up.

So back to drawing board. Still exploring how to harness light sensors to control light output based on daylight and nightlight needs.


6 years ago

I am lousy at drawing things so here are some tips to go googling again:

1. Buy any USB thingy that plugs into your cigarette lighter or use the second outlet or free port when your phone is charging.

2. Buy any regular USB cable - one end should be able to plug into that USB/cigarette lighter adapter. 5 volts comes out of it.

3. Look up the wiring diagram for a USB male plug - find out which contacts are the +5volts power and the - ground.

4. Clip off the plug at the end of the USB cable you are not using. Using a multimeter or with an LED/flashlight bulb, wires and battery, trace the corresponding wires to the power pins in the plug.

5. Look up LED calculator. Pick any application that you can input in the specs of your LED from the package or datasheet to calculate the correct resistor to use that keeps the LED from burning out.

6. Solder the resistor to either leg of the LED. Determine which way the LED needs to be connected to the + power lead and which one to the ground wire.
Connect one of the leads to the correct power wire.

7. Attach a shorter length of wire to the other LED leads. Connect that to the switch. Connect the other lead on the switch to the remaining power lead.

8. Insulate the bare connections. You can use electrical tape or heat shrink tubing which probably would have been step 5a.

9. Power it up and see if it works. If not, go to step 3 and check your wiring and see if you need to reverse the connections of your LED.

Good luck.


Reply 6 years ago

Thanks Caitlinsdad

Question... I am trying to bypass the circuit through Soft touch momentary push button switch. Its function opposite what I want. Still scratching my head. Do not press button, its led on. Press the button, led turns off. I want press the button and turn on the led. Scratching my head.

How do you reverse connections of led? Forgive me being ignorant.


Reply 6 years ago

An LED has two wires coming out of it. One must be hooked up to the positive power lead and the other to ground. The LED will not light up if not properly connected. I am saying if the LED does not light up, then desolder and swap those two wires with each wire going to the other LED connection and resolder.

Seems you have the wrong switch which is a Normally CLOSED type. You need a Normally OPEN momentary switch which breaks the circuit all the time when no one presses it.


Reply 6 years ago

Bingo! When you kept saying Ground, I immediately googled LED with Ground. Discovered what I was doing wrong. I was routing the Lead and ground wrong on the button. I did connect both lines to button and got opposite result. When I limited to just lead line, it worked perfectly.

Led wiring was perfect by dumb luck yet glad found it. I did not know Led has positive and ground.

Now since I have schematics drawn. I will begin to make it pretty and finish the project in best condition as possible. Then show my finished product.

I wonder if I can submit my project to Hand on learning contest?

Let me know.


Reply 6 years ago

One more thing to add... I do not have multimeter and wonder how much it will impact my resistor? I have tons of 1/4 watt, 5% tolerance. Only thing I am not sure which color code to bring my Ohm to around 70-80 ohm. Just trying to think outside of box and make educational guesses.


Reply 6 years ago

Look for something grey-orange-black-black or violet-grey-black-black.