Putting Bluetooth headphones within my ski helmet
THE IDEA
While skiing I like to listen to music. Usually, I would just put earbuds under my helmet, but this can lead to them falling out or pain from the added pressure. Therefore, I decided to incorporate headphones directly into my ski helmet.
PROJECT GOALS
For this project, I wanted to hear music through my helmet in the most seamless way possible. I also wanted to incorporate Bluetooth into the device.
MATERIALS
Starting off this project I knew that I would need 4 basic items: Speakers, speaker wires, a Bluetooth receiver, and a battery. I also wanted to keep this project relatively cheap at about $30 not including the price of the helmet or batteries.
FIRST STEPS
The first thing I did in this project was take apart my sisters $5 headphones in order to see how cheap headphones work. These headphones had 2 inexpensive drivers connected directly to R/L positive/data (respectively) and a common ground. From this, I figured I could just buy 2 headphone drivers and connect them directly to a 3.5mm headphone jack wire. Off of Amazon, I bought a set of headphone speaker drivers (link 1), and a Bluetooth module for Arduinos (link 2), both for a total of $33.18. This was a little overbudget but still doable.
THE FIRST MISTAKES
My first mistake was the Bluetooth module I bought. This module could be run off of a standard phone battery bank, but no combination would fit seamlessly (a design goal). I later changed to an integrated Bluetooth receiver + LiPo battery (link 3). This brought the total cost to $33.98, as I had returned the old Bluetooth module. This was a slightly greater cost than before but this Bluetooth module included a battery.
BUILDING THE PROJECT
Once all the necessary components arrived, I did testing on both the speakers and Bluetooth receiver to check if they worked. After this preliminary step, I started taking measurements of each component. The speakers needed a housing to prevent damage and they had to fit seamlessly in the helmet’s limited capacity. I then designed and 3D printed my own speaker housings with holes for wires to exit from. These housings used a interference fit that had to be hit into place to lock the pieces together. (File 1)
After this step, I soldered on each wire for the speakers and connected everything for testing. Everything worked as planned and I proceed to test the fitment inside the helmet. The speakers and receiver all fit well and were even sleeker than I had estimated.
PROJECT TAKEAWAYS AND LESSONS
This project was a nice and simple helmet modification that took < 3 hours of design, concept, and building time, as well as being better than I had initially imagined. During this project I learned about how speaker drivers function, sharpened my soldering skills, and lastly gained more experience in making functional 3D prints. Overall, I am very happy with this project and would recommend it to anyone with a couple hours and a 3D printer.
PROJECT NEXT STEPS
I could improve this project by adding a USB-C wire for charging that hangs out of the helmet so the receiver does not need to be removed every night. As well as this, I would buy a bigger LiPo battery to get more life out of the receiver.
FINAL PICTURES
LINKS
(Headphone speaker drivers) https://www.amazon.ca/gp/product/B08DKN5SD2/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
(First bluetooth module) https://www.amazon.ca/gp/product/B07NRB51KD/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1
(Second bluetooth module) https://www.amazon.ca/gp/product/B085VWQKW8/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1z
MY FILES
40mm Speaker housings https://www.thingiverse.com/thing:4690877