Introduction: Ultrasonic Bone-Conduction Speaker Gun

I created a device that can pick up ultrasonic sounds, transmit them into the range of human hearing, then transmit that through a bone conducting speaker to allow only the user to be able to pick up on high frequency sounds around them.

Step 1: First Plans

My first plans to create an armband to house all the components and allow for bone conduction through the elbow had a few issues I didn't realize until after I had already begun my project. For one, the ultrasonic sensor used was going to be too large to be housed inside a small armband, and for two I didn't take into account what kind of frequencies the bone itself is good or bad at conducting. I learned that bone is better at conducting lower frequencies, and I was strictly working with higher frequencies. So in order to fix this issue I had to create a device to house the bone-conducting speaker closer to the head. I settled with a sports glove that Had a finger attachment that housed said speaker, so that one could press the speaker against the temple and be able to pick up on the higher frequencies emitted by the ultrasonic device.

Step 2: Tools and Materials

Tools needed are:

1. Flat head screwdriver

2. Soldering Equipment

3. Glue gun

4. Sewing needle and thread

5. Pliers

6. X-acto knives

7. Dremmel tool or small saw

Materials needed are:

1. Stereo Ultrasonic Sound and Bat Detector kit ($27.95)

2. Stereo 2.1W Class D Audio Amplifier - TPA2012 ($9.95)

3. Bone Conductor Transducer with Wires - 8 Ohm 1 Watt ($8.95)

4. Aux cable

(I used an old one that was lying around)

5. 3.5mm Stereo Female Audio Socket Headphone Jack PCB Panel Mount Connector 5 Pins for Arduino (10 pack for $6.99)

6. Sports Gloves ($5.90)

7. Lithium Ion Polymer Battery - 3.7v 150mAh ($5.95)

8. Water Squirt Gun ($5.99)

9. JST 2-pin Extension Cable with On/Off Switch - JST PH2 ($7.95)

10. Some extra wiring for extending the microphones on the Ultrasonic device and for the Audio Amplifier.

Step 3: Put Together the Ultrasonic Sound Detector

First I assembled the Ultrasonic Sound Detector by following the directions given on their website.

Step 4: Put Together the Ultrasonic Sound Detector Continued...

I had some issues with the soldering not sticking to the joints, so that messed up my LED, which didn't end up working. However that didn't seem to affect the device overall.

Step 5: Assemble the Audio Amplifier

This one was a little tricky because I had to adjust a few things. But I found some videos that helped me out with the assembly of the audio amplifier.

Here are a few links to video instructions and circuit diagrams of the audio amplifier assembly:

I wasn't able to find the same headphone jack as was in the instructional video, so it took some searching to figure out the correct pins to solder to when adding the audio jack to the entire assembly. I discovered it is the 1 (ground), 5 (left), and 3 (right) pins to connect.

Step 6: Create the Glove

So i was in a slight rush to make the deadline for this project, and ended up using a wire to sew some of the fabric pieces together. I dont recommend doing this as it took a lot longer and looks a lot messier.

For my glove I took some extra strap material and sewed it to the glove to create an extension for the speaker to sit in. I would recommend using an actual fingered glove which would create a more stable hold for the speaker. However, this design worked for the purpose intended, it just didn't look very pretty.

As for housing the Audio Amplifier device I create a small bubble-esque shaped shield to contain and protect the components on the back of the glove. I left one side open so I could still remove the battery in order to charge it.

I hollowed out a small area to allow the on/off switch to pop through for easier powering up and down.

Step 7: Create the Gun

I ordered some squirt guns off of amazon that I liked and that would fit the Ultrasonic Sound Detection device. I used x-acto knives and a small saw blade to create an opening that would allow the dials, on/off switch, and aux port to remain accessible.

In order to make the device fit inside the squirt gun I also removed the battery pack from the device and attached it to the outside of the gun itself. I had to cut and re-solder the wires after threading them through a small hole I created on the side.

Lastly I ask had to use the extra wiring to extend the microphones. I created small holes on either end of the squirt gun so that the microphones could stick out through the end, allowing them to still be able to pick up sound clearly. I used small amounts of hot glue to keep everything in place.