This project is aimed for beginners, but can be reproduced by anyone! The circuit consists of a coin cell battery powering an LED, but is resisted by a sensor of your choice.
If you liked this ible, be sure to leave feedback. Thanks and enjoy!
Step 1: Materials
--20mm coin cell (Sparkfun, Radioshack)
--20mm coin cell holder (Sparkfun, Radioshack)
--3mm LED (Sparkfun, Radioshack)
--Copper tape (Sparkfun, Amazon) or conductive ink (Bare Conductive)
--Card stock paper or thin cardboard (I am using card stock throughout this instructable)
--Hobby knife or scissors
--Multimeter (optional, for debugging)
Sensors (there are many possibilities):
--Photocell (Sparkfun, Radioshack)
--Flex sensor (Sparkfun)
(The description of each sensor is in the next step, or check sparkfun for a better one.)
Step 2: Design the Circuit
The source: This will be your 20mm or 12mm coin cell. The size of the cell doesn't matter, but the 20mm one will last longer.
The path: This is the copper tape used to connect all of the pieces of your circuit together. This is the most difficult part to design in this project.
The load: This consists of your sensor of choice, as well as the LED.
The control: This will be the button.
Knowing this, we must sketch a circuit containing all four. The easiest way to do this is in a series circuit. That means there should only be one path for the electrons to flow. See the pictures for details.
First, choose your sensor. The options are as follows: photocell (or light dependent resistor), thermistor (changes resistance based on the temperature), trimpot (a small potentiometer), SoftPot (changes the resistance depending on where it's touched), or a flex sensor (changes resistance based on how bent it is). It is important to note that if the sensor has three pins, any two consecutive pins are used. These are just some possibilities, for there are many more I haven’t listed here. Edit: Now there's a video demonstration!
Next, choose the favored LED. Any color or size will work, but it's preferable to keep it small.
Finally, choose the battery. The bigger it is, the longer it will last, but, again, it’s desired to keep it small.
Step 3: Test the Circuit
Place all of the components in their proper locations on the breadboard for testing (see pictures for reference).
Step 4: Design the Trace
As I said before, the best way to make this circuit is in series. This can be achieved by connecting all of the letters together consecutively. It's sometimes easier to underline the whole thing to complete the circuit. This can best be portrayed through pictures, so be sure to read the annotations.
The VCC (+) and GND (-) are the leads of the cell.
The red line is a guide to show you the direction of electron flow, and that it is a series circuit. You might ask: But the path splits, so is it still in series? Well, there is no resistance between the points when they split and join, therefore making it a series circuit.
Step 5: Make the Trace
Start with a simple sketch of where the copper tape or conductive paint will be placed.
If you're using conductive ink: draw over your sketch using the ink. Be sure to put the components on before the ink dries!! Now you can go directly to step 7.
If your preferred method is using copper tape: cut all of the pieces to the correct shapes needed to make the letters (see the pictures).
Stick the small pieces of tape onto the sketch first, then add the rest on top.
Step 6: Solder the Componenets
If needed, double up the card stock paper for stability (the coin cell needs to be held firmly in place).
There are some great guides on soldering here.
Important if you don't want to solder: The tape I was using didn't have conductive adhesive below it, that's is why I had to solder all of the joints. Technically, it is possible to do this without soldering, but it's pretty unreliable: you must place a layer of tape over the leads, as well as stripping them (shown in pictures). If you do this, it would be smart to test the connectivity using a multimeter's continuity feature (also pictured).
Step 7: The End!...
Use this as long as you want, and the circuit isn't very power-intensive so it'll last awhile.
It's super versatile!!! (notice how the LED doesn't even flicker)
And looks amazing in action!!!
If your circuit doesn't work, here are some possible solutions:
--Check what should and shouldn't be connected. You might have to refer to your sketches for this one.
--Check the cell's voltage. If it's under ~2.9V you need a new cell.
--Make sure the LED, cell leads, sensor, and button are soldered correctly to the tape.
--Make sure the flat side of the LED is going towards the negative cell terminal.
Step 8: ...But Wait, There's More!
--Make it into a PCB.
--Make it even smaller!
--Create a different output (small vibration motor?).
--Add an alternative energy source.
Be sure to check out pinomelean's ible on making a paper theremin here!
Thanks a lot for reading!!! Be sure to leave feedback.