Sometimes, not very often I got really bright ideas. And I'd like to have some indicator that IDEA IS COMING, so my friends or family can hide before I begin explanation. And then one day I found an awesome instructable how to make "Mysterious Lightbulb Prank" by Kipkay. That was just what I want! But three things didn't give me rest:
- Batteries were buried inside the light bulb.
- Only married guys can turn it on (or at least those who wear a finger ring).
- The LED was placed not inside but under the bulb. That doesn't look like a real light bulb.
I'd like to find the way how to avoid these issues. And then I saw REMIX CONTEST. That was my chance, my incentive to start and complete the project.
Here is what I got:
Step 1: The Light Bulb Parts
I didn't want to use a battery to supply the LED inside the light bulb. And I didn't find an accumulator small enough to fit inside the lamp base. So I decided to try a supercapacitor and the issue with power source was closed. Definitely, that was one of my bright ideas: small, one minute to charge and there's no need in complicated charges.
Next question: how to turn on the light? In "Mysterious Lightbulb Prank" project the LED was powered when both contacts on the bulb base were closed by the finger ring. I'd like something more elegant. Skin resistance!
And the last question: how to charge the supercapacitor? I have to add a diode to charge the supercapacitor through the same two contacts of the light bulb base.
These are what I used in my idea light bulb:
- Two E27 light bulbs. At least one of the pearl colored.
- 1 Farad supercapacitor EECF5R5U105 (C2).
- Two LEDs BL-L48UWC (D2, D3).
- Two transistors C33716 (Q1, Q2).
- 1KOhm resistor (R1).
- Diode 1N4007 (D1).
- 10nF capacitor (C1).
Step 2: Prepare the Light Bulbs
I think that's the hardest part of the project. Light bulbs have a terrible glue! And when you free the bulb you should gently cut it near the bottom and take off all the inside parts.
I suggest making a scratch first. Then take a solder, warm the scratch while turning the bulb. The scratch will be wider and wider and finally the bottom part of the bulb will fall off.
Step 3: Assembling the Idea Lightbulb
First of all I mounted two transistors between the contacts of supercapacitor. And that was the framework for all other parts.
I used hot glue to fix the supercapacitor inside the light bulb base and to fix the bulb on the base.
Be careful and don't touch the inside surface of the bulb. It is very easy to rub off the colored layer. That was my mistake and that's why you can see transparent stains on pearl colored bulb in my video.
Step 4: Bulb-holder Parts
The holder has some magic too. It should charge the light bulb and it should turn it on. Frankly speaking, turning the switch on means cutting off the USB power and connecting 1 MOhm resistor to the light bulb base. In this case power source is supercapacitor inside the light bulb. And when the switch is off the supercapacitor start charging.
These parts we need for the holder:
- Any E27 bulb-holder.
- USB cable with USB-A male plug.
- 13 Ohm 2W resistor (R1).
- 1 MOhm resistor (R2).
- SPCO switch (S1).
And don't forget flux for aluminium soldering. The light bulb base is made of aluminium.
Step 5: Assembling the Bulb-holder
Just make two holes in the bulb-holder: for USB cable and for the switch. After soldering I used hot glue to fix all the parts inside the holder.
The metal spring on the photo doesn't make sense. That's just my concept of beauty.
I wish you to light the Bright Idea Lightbulb everyday. Good luck with your DIY projects!
P.S. Wish me to win an Instructable T-shirt, please...