This project was made in the MRL Research Lab at Bergen County Academies.
Hello! Today, I will show you how to make a pair of noise - increasing headphones for people who want an inconspicuous way to increase their hearing. This device increases hearing to almost superhuman levels of sensitivity.
Step 1: Gathering Materials
This project requires a few different materials, all of which should be relatively easy to find at an electronics store or a Home Depot.
You will need:
1 pair of construction headphones
1 pair of electronic headphones. Note that these headphones have to be easy to take apart. Don’t buy anything too expensive for this part of the project, as the headphones will be taken apart. Furthermore, the ear cup must be roughly the same size as the ear cup of the construction headphones, otherwise they’re useless as they will not fit.
1 roll of double - sided tape. We won’t be using that much, so if you can just buy a strip of it that would be even better
1 battery pack. This battery pack has to hold 3 AA batteries or the equivalent charge, as too little charge will not power the headphones, and too much will burn out the circuits (Trust me on this one)
3 AA batteries, or the equivalent power for the battery pack.
1 electronics switch. If you don’t get this, your headphones will most likely burn out because of the extended time of them being on.
1 LED diode. A color that is easily visible during day and night is your best choice, as if you can’t tell if your headphones are on, you will waste the battery.
2 Electret microphone amplifiers.
About 10-15 zip ties. You may need more or less depending on the size of your headphones. You should get zip ties on the larger size, as the battery pack will be eventually zip tied down to the headphones. 4 small bundles of thin wire. This wire also has to have insulation, as you will see why later in the project. It is strongly recommended that you get 1 bundle of red and 1 bundle of black wire, as well as 2 bundles of different colors.
2 pieces of wire that are different colors from everything above.
8 pieces of heat - shrink tubing for thin wires. You may need more if you’re inexperienced with a heat gun, like I am.
1 small piece of Styrofoam. You won’t need too much of this, as you will only need two pieces about the size of the Electret Microphone Amplifiers.
1 wire tube. You’ll probably need about a foot, as it will have to go around almost the full extent of the headphones. You will also be cutting this into two symmetrical pieces later in the project.
2 resistors (I don’t know how much they resist as of now)
Electrical tape. You will only need this in one section of the project, so ask to borrow some or get a smaller roll that way you don’t waste money.
You will also need access to:
Hot glue gun Sandpaper or sanding station - Sand grit really doesn’t matter, as the only purpose of the sandpaper is to get rid of material as you will see later in the project. Soldering iron Heat gun Scissors Wire snips
Step 2: Starting the Project
You will need both pairs of headphones, 2 or 3 extra zip ties, and access to wire snips and a hot glue gun.
Part 1: Cut away the top part of the headphones to reveal the wires. DO NOT cut the wires, otherwise your project will not work because it cannot transmit sound. Next, pop out the foam ear covers, then pop out the speakers to have the speakers and wiring hanging on the body of the headphones. Finally, remove the wires from the body of the headphones without breaking them to get to your result, 2 speakers attached by wires.
Part 2: Because construction headphones do not have any electronics inside of them, you can simply pop out the foam ear covers to reveal the hollow inside. Save these for later, otherwise you will either have to buy replacement ear covers or make someone’s ears miserable.
Part 3: Next, use a combination of the wire snips and sandpaper to get rid of all of the excess plastic around the speakers until they can fit inside of the construction headphones comfortably. This does not have to look good, but it does have to leave the speakers undamaged. Note that in the next part you will need space where hot glue is safe to use on the speakers, so leave about ½ of an inch so hot glue can be applied. Then, sand off a small section on the top of the construction headphones, so you can notch the wire in without breaking it.
Part 4: Apply hot glue to the back of the ear cushions, then stick the speakers onto them where it looks like they would if they were inside of the original headphones. If the foam part is facing you, you have stuck it right. Finally, snap the cushions back onto the construction headphones, leaving a piece of wire hanging off. Secure it with a zip tie for now. Do not cut any part of the zip tie off, as you will use these later.
Step 3: Putting the Amplifiers Together
You will need the 4 small bundles of wire, the wire tube, all of the heat-shrink tubing, double - sided tape, and access to a hot glue gun, scissors, wire snips, and a soldering iron.
Part 1: Before you start, make sure that you can solder decently, or have someone around who can. It took me many, many tries to get the solder to stick without being so big that it made the heat - shrink tubing not fit. Solder the black wire to the pin under “GND”, the red wire to the pin under “VDD”, one of the other colors (I used yellow) under “GAIN”, and the last other color (I used blue) for “Out”. Do this for one of the microphone amplifiers, as you will see later what you will do with the other one.
Part 2: Slide the shrink - wrap tubing onto the part where the wire and pin meet. Then, use the heat gun to shrink the tubing onto the soldered part. Try to direct the heat gun as best you can, otherwise you might damage the microphone amplifiers. Again, do this for the same one of the microphone amplifiers.
Part 3: Stick two pieces of double - sided tape onto the middle of the headphones. Then, using the hot glue gun, stick the wire tube directly onto the headphones, like so. Unlike in the picture, you will not be using the zip ties yet. You will do this when the wiring is done, because zip tying the tubing makes it harder to access the wires.
Part 4: Slide the headphone wire and 4 - colors of wires through the tubing onto the other side. Then, repeat steps 1 and 2 for the other microphone amplifier.
Step 4: More Wiring
You will need the protoboards, the resistors, the zip ties, and access to the wire snips and soldering iron.
Part 1: On the side of the headphones where you want less stuff getting in your way (I picked the right side) cut out a 4 by 9 section of protoboard, and cut the blue wire like so.
Part 2: Examine the wire pattern as seen above, then solder the wires and resistor to the back of the board once you are done placing the wires and resistor. Place zip ties around the section leading up to the top of the headphones, as you will not need this anymore.
Step 5: Wiring the Battery Pack
You will need the battery pack, double - sided tape, electrical tape, styrofoam, AA batteries, zip ties, and access to wire snips and the soldering iron.
Part 1: Using the double - sided tape and a thin piece of styrofoam cut to the size of the battery pack, attach the battery pack to the top of the headphones as seen in the first picture.
Part 2: Put the batteries into the pack. This will not drain their battery, as the battery pack is not connected to anything (yet).
Part 3: Take the blue and yellow wires, and then, using the zip ties, attach them to the battery pack as in the second picture.
Part 4: As shown in the 2nd picture, use the electrical tape and soldering iron to solder the wires from the battery pack onto the wires from your headphones.
Step 6: Wiring the Other Side of the Headphones
You will need the power switch, electrical tape, resistors, LED light, protoboard, heat - shrink tubing, double - sided tape, headphone jack, zip ties, and access to the soldering iron and wire snips.
Part 1: First, zip tie the top of the wire tubing, as you will not need access to this portion of the tubing anymore.
Part 2: Next, use one of your two unused colors (I used green) and snip off a small portion that can at least reach between 7 holes comfortably diagonally. Solder it to the blue wire coming from the opposite side, then use a piece of heat - shrink tubing to make sure the connection stays steady.
Part 3: Then, solder as shown in the first picture, making sure that every single metal piece gets soldered to the bottom of the protoboard.
Part 4: Using the double - sided tape, tape the protoboard to the wire tubing. Then, using the zip ties, zip tie the end of the wire tubing as shown in the 2nd picture.
Step 7: Common Problems With Headphone: FAQs
Question 1: What if my heat - shrink tubing comes loose?
Because heat - shrink tubing almost always goes over soldered pieces, you have to de-solder your soldered pieces first. Then, put the heat - shrink tubing over one of the loose ends of the wire. Re-solder, then place the tubing over the soldered part and reapply.
Question 2: What if my headphones stop working?
There can be a multitude of problems with your headphones that simply makes them “stop working”. The best way to test your headphones is to follow the path of the noise and see if the components at a certain part of the headphones work. For example, if everything is affixed correctly, it means that the batteries are dead or the amplifiers are burned out. Through process of elimination and by following the path of the noise, you can isolate the problem.
Question 3: What happens if I keep the headphones’ power on for too long?
If you keep your headphones on for too long, the microphone amplifiers will burn out and you will have to get new ones.
Question 4: What happens if the batteries die? How should I put new ones in?
To take out batteries, you have to have on hand: 3 AA batteries, a zip tie, double - sided tape, and access to wire snips. Snip the original zip tie, removing it from the incisions on the headphones. Pick up the battery pack from the headphones and rip off the old double - sided tape, as it will not hold if you try to re-stick the battery pack. Replace the old batteries with the new ones, while being very careful not to rip the zip tie containing the wires on the battery pack. Put the double - sided tape onto the battery pack. Put the zip tie through the hole on the bottom, then stick the battery pack directly above it. Close the zip tie, then cut off the excess.
Question 5: How loud are these headphones?
As stated from many people who have used these, “I can hear everything around me”. When I said that hearing increases to near superhuman levels, I was telling the truth. If you know that you have hearing sensitivities, do not put them on. It will hurt your ears and may damage them.
Question 6: What should I do if *X* breaks?
Fix it: Construction headphones; Electric headphones (If you break the body); Wire tubing
Buy it: Microphone Amplifiers; Battery Pack; Electronics; Protoboard; Electric Headphones (If you break the wires)
You have replacements: Wires; Zip ties; Styrofoam; Heat-shrink tubing