Introduction: The Engineer's Proposal Ring

About: So basically i am a crazy person, who loves to think the most odd way ever possible,who makes what he thinks and also let other also make those . Check out my crazy projects if you like do follow me :D
"Marriage is a book of which the first chapter is written in poetry and the remaining chapters in prose."

Engineers are too techie that sometime they are misunderstood for their way of being romantic.I so disagree that ,engineering has it's own art.In my case i believe to be always unique when it should come to show how much you love your girl.
I accept platinum is the best proposal ring material , but why not put the brain to creativity and see how some basic electronics stuff can make a beautiful proposal ring.

The Best Part of the Ring

As we know every proposal has two answer it can be YES an NO.

If the answer is


The led glows

So if you like this project do make sure that you vote for it , in the wedding contest/Comfort zone .

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Step 1: The Challenge

So the main challenge was to make a electronic ring that lights up when you wear it.

The main challenge in making one was

  • Things should be compact that mean power source should be too small.
  • It should turn on when worn

All the items used will be easily available and totally salvaged and recycled.

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Step 2: Part List

Electronics part

you will get the ferrite from an old ballast and the other at a local radio shop the cost here is 0.15$in total

  • A ferrite torroidial core
  • 2X 10-15 cm long thin wire
  • 1 k resistance
  • 2N2222 transistor

Hardware part

you need to buy this from a local gas station or hardware station

  • 1 gas pipe tightener ring


You will need the following tools

  • soldering iron
  • scissors
  • glue gun
  • twezzer

Step 3: Power Choice

Power choice would be very obvious to say that it would be a button cell bcecuase they

  • Light weight
  • High power
  • Variety of dimensions

Lets see the common type of button cell


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This CR-2025 lithium battery, often called a button battery, is a 3 volt battery that looks like a coin. Environmental friendly, ideal for cameras, calculators, watches, toys and other electronic devices Works in both low & high temperature operations. With this high power lithium technology, it offers reliable maximum power and a lifetime value for small devices.

Battery Specifications

  • Nominal Voltage: 3 Volt
  • Capacity: 160–165 mAh


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The CR2032 Battery Battery provide an excellent combination of high energy and continuous voltage supply. CR2032 Battery is a high-energy, coin-cell lithium battery that lasts longer than silver-oxide batteries and is great for use in watches, medical devices and other electronics. Suitable replacements for brands like Duracell®, Eveready and Panasonic®. These batteries provide long shelf life for back up energy purposes together with ideal temperature resistance and superior storage capacity. This lithium coin batteries are guaranteed to provide optimal performance throughout the life of the battery. CR2032 Battery is ideal for cameras, wristwatches, electronic agendas and games, and calculators.

Battery Specifications

  • Voltage: 3
  • Capacity: 210


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AG10 Battery is a button shape alkaline battery with a nominal voltage of 1.5V. The AG10 Battery is a 1.5V alkaline button cell battery that is used for small electronic devices. It is a popular Alkaline button cell battery commonly used in cameras, calculators, toys, and watches.

Battery Specifications

  • Nominal Voltage: 1.5 Volt
  • Capacity: 180 mAh


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The AG13 / LR44 / L1154 Battery is a primary cell battery, and it is non-rechargeable. The AG13 Battery is a small and economical Alkaline battery with a nominal voltage of 1.5V. This alkaline button cell battery provides long power life and excellent continuous power sources to your device. Works effectively in both low and high temperature. An alkaline battery is a battery that uses manganese dioxide and zinc to create a reaction, and it is an economical alternative to silver oxide batteries, while still providing high capacity and long usage.

Battery Specifications

  • Nominal Voltage: 1.5
  • Volt Capacity: 80 mAh

The Winner

LR2032/LR2025 has High capacity but due to less size AG10 /AG13 is the winner but there is a problem how to make the voltage from 1.5V to 3.0V

Step 4: Joule's Thief

What is a Joule Thief ?

A Joule thief is a circuit that sucks every bit of electro-chemical juice out from a battery and drives a output more than the battery voltage.

It is a self oscillating voltage booster and are highly used DIY torch project to drive a led at 1.5V battery .

How does it work ?

The circuit works by rapidly switching the transistor. Initially, current begins to flow through the resistor, secondary winding and base-emitter junction which causes the transistor to begin conducting collector current through the primary winding. Since the two windings are connected in opposing directions, this induces a voltage in the secondary winding which is positive, which turns the transistor on with higher bias. This self-stroking/positive-feedback process almost instantly turns the transistor on as hard as possible (putting it in the saturation region), making the collector-emitter path look like essentially a closed switch (since VCE will be only about 0.1 volts, assuming that the base current is high enough). With the primary winding effectively across the battery, the current increases at a rate proportional to the supply voltage divided by the inductance. Transistor switch-off takes place by different mechanisms dependent upon supply voltage.

Step 5: Making the Circuit on Breadboard

It was due to make's super easy video that helped me make the joule's thief

The steps are as follow :

  1. Take two wire and round them around one end
  2. Wound the wire around the torroid ferrite core.
  3. Wind it around the torroid for 8-9 times.
  4. After that separate the two wire.
  5. Take one of the end of the two wire.
  6. And solder it to the other wire one other end.
  7. Solder a 1 k resistor to it .
  8. solder the 1k resistor to the base of 2N2222
  9. the collector is coll

Step 6: Making the Ring

Now the first challenge fitting all the circuit on the to a ring , i was thinking alot of material to chose , like wires and pvc ring when i saw pipe tightening ring in my house.
this was the perfect one for my build because

  • IT had a good surface area to stick all the components
  • My girlfriend's ring finger is a little trouble some to find ring at-least for me so if this one has adjuster.
  • This is easy to find for anybody so universal build

Step 7: The Switch

The turning on of the ring was a challenge itself because i wanted it to turn the led on when the ring is placed in hand.
in-short the answer is Yes.

Possible solution i thought

  • Using two aluminum foil sheet .
    Foils are good conductor of electricity and so it was considered to be used for making a build the manual switch .

why it is rejected ?

The foils would be damage after some use (it did damaged while making only :P )

  • Using push button

Push button are great for this case but the challenge was again to use one that is very small.
And also how the triggering will be done. Luckiliy i had some old salvage ipod push button that came in handy and i used them for the build

Step 8: Sticking Everything on the Ring

The last thing was to glue everything on the ring .
Using the glue stick i glued the ferrite core first.Then glued the transistor and the resistor on the both half and then added the switch on the reverse side of the ring. so that when it wore due to pressure the switch is pressed and the ring glows and the answer is "YES"

Step 9: A Little Fun With the Ring

I and my sister was decided to make some light trails run with the ring so we tested it with a exposure of 10 sec and 100 iso in a dark room.
We were doing some random motion and here's what we got.

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Wedding Contest 2016

Participated in the
Wedding Contest 2016

Beyond the Comfort Zone Contest

Participated in the
Beyond the Comfort Zone Contest