Toasty Tunes - Wireless Audio Beanie

About: Electrical Engineering Student & Hobbyist

What is Toasty Tunes?

Toasty Tunes is a wearable gadget that lets you listen to music through bluetooth and also keeps your head warm in the process, all in a discrete manner, hence its name "Toasty Tunes!"

Roughly three years ago in February, I thought up this project a little bit of time after my mother showed up with this Timberland hat in the photo that she had found lying on the ground somewhere of which she cleaned and gave to me (rest assured, the owner was likely long gone as no one was around).
By the end of this Instructable you'll see that this was a very budget build in terms of how much I spent.

That past year I'd discovered such a thing as the Logitech Bluetooth audio receiver and thought it was pretty cool and later found out that there was this version I'd used for a significantly cheaper price and did the same thing while using less power. Yes the audio quality and range was what suffered in that trade-off but it was not a priority to me. As a result I combined the USB audio adapter I'd bought from Aliexpress that year with the hat. I needed some speakers and I thought back to the Audio pencil case I owned but didn't use so I removed those two 0.5W 8Ohm speakers to use in the project. I assumed they worked with the design since the pencil case didn't require any power to play audio.

The LiPo came from a drone I'd manage to get from Value Village for $2 along with it's charger which is what I use to charge it. It looks like this: https://ebay.to/2VfEJDn. The female JST 2pin connector was also in the drone's system so I decided to use that as well in this build.

Going into this project I was in around grade 10 or 11. I hadn't done any electronics projects of my own, so most of my basis was going off of what the internet said about diagrams of components and hoping for the best when I saw either a working device or a spruce of fire in front of me. An example of this was feeding a USB Audio Adapter (had a USB connector implied needing 5V to me) 3.7 V from a LiPo battery. It very well could have worked or not worked, it really depends on the circuit of the device being powered. I didn't know how to sew either which was alright I suppose? I still don't know formally to this day but I figured they just move the needle with the thread tied to it in and out of the material and tie it every now and then, so why couldn't I do the same? The only bit of experience I had was probably soldering because I'd previously modded my 3DS to use a modchip that mapped the console's controls to also accept external controller inputs like that of a Gamecube controller. In that event my father taught me how to solder and it opened up a lot of doors for me. That was also where I learned how to use heat shrink tubing since the input of the modchip was some female header pins so my father and I had to make an adapter that was one part female gamecube port and male header pins for the modchip. You may find the modchip I used in that build here: https://bit.ly/2NoqERA.

After Toasty Tunes was done, I was pretty pleased with the results. It worked as I thought it should, I gained some more soldering and "spotty" sewing experience as well as something else to say I've done when I was bored. :)

I hope you enjoy reading this and making this too if you choose/you find it good enough to follow. As always please let me know about the recommendations or edits I should make as I do appreciate the feedback (this project was mostly self-learning and nothing formally taught in school).

Step 1: Bill of Materials (BOM)

Main Parts:

  • Beanie (any is fine but preferably one that is thick and stiffer so it can flop the electronics less)
  • USB Bluetooth Audio Adapter (the one in the photo is pretty reliable for the price of around $2-5, make sure to also gather a 3.5mm AUX cable if the model you buy doesn't come with one. another option is directly soldering from inside the adapter's audio connections to some external wires)
  • Female USB connector

  • 3.7 Lithium Polymer battery (the one that I used had a 350 mAh capacity which suited my needs but I wouldn't recommend going under 250 or so since we are under feeding the supply to the Audio Adapter which operates at 5 V and the fully charged LiPo should reach 4.2 V. I believe the larger the capacity in mAh, the longer it can stay at a higher voltage)
  • Snap Switch (any latching type of switch will work)
  • 24 AWG wires (higher gauge will save space but are harder to work with in soldering, lower gauge will take be bulkier in the design but be better for current travel)
  • Heat Shrink Tubing (should roughly surround the wires with a max of 1-2 mm of space all around the wire for tighter results)

Tools:

  • Thread & Needle (colour doesn't matter but will look better if it closely matches the hat colour, width doesn't matter too much as I used quite thin sized thread but too thin will easily break, try to pull it with your hands before using it)

  • Wire Strippers (should include a spot to cut the wires too so that you don't dull your own pair of scissors)
  • Tin Solder(lead or no lead is optional, lead will be easier but I prefer no lead to be a bit on the safer side, make sure it includes rosin which is a flux material allowing for better soldering)

  • Soldering Iron (an iron that is roughly 40W is preferred since any less may not be hot enough to easily melt solder and upwards to say 60+ W can be too hot and easily burn components when held to electronics for short periods of time [3-7 secs. depending on the temperature] )

*Optional*:

  • 5 V Boost Converter(this voltage stepping up transformer board will make sure the audio adapter receives 5 V continuously but the capacity of the LiPo battery will shrink by around 25% since 5 V to 3.7 V is more by 25%. I find that the audio sounds fine and range is about the same despite the step up but it's always something to be explored)
  • Mercury/Gravity Switch (since Mercury is toxic, it's less recommended to use that as a means of turning on/off the system but if protected with an outer padding or case the glass can be alright. I assume the beanie won't be roughed up too much.)

Step 2: Putting the Circuit Together

Here's what the circuit looks like. It's identical to my first prototype of Toasty Tunes. The only difference is that the slide switch in the diagram was a Mercury switch. I had a lot of them just lying around so I thought why not. The good part about it was that I put the Mercury switch pointing upwards in the sowing so that essentially when I put the hat on it would turn on, but if I took it off and lay it flat on the table-it turns off. This was good for a while until I decided to go skateboarding outside with it on with it connected to my phone, since I was skateboarding in the neighbourhood the pavement was pretty rocky. When it was really rocky, my skating would get fairly bumpy and as a result the Mercury in the glass casing would bounce up and down, causing the system to turn on and off over and over which was not to my liking. My solution to this was bridging the connection from the battery to the system where the Mercury switch was. It was okay because the the other end where I connected my LiPo battery had a 2 pin male JST connector which fit the LiPo's connector perfectly. Therefore to turn the system off I just had to manually disconnect the male JST connector of the system from the battery's female JST, which is fine for my requirements when using it.

Step 3: Soldering of Components

A key part of making the circuit of Toasty Tunes would be the soldering of the components together after they've been gathered. Once you have all the components you will need to connect them together reliably with the bonding of solder. Here is a great tutorial to get you going if you have not soldered before: Soldering Tutorial It's simple and requires some practice, but definitely is not a difficult task to do.

After you feel comfortable with your soldering abilities and maybe practiced a bit, you can start soldering the wires in the schematic together. But before you start soldering wires together, start off by cutting some heat shrink tubing the length of the exposed wires and pull it back so you can solder the wires. When the wires are soldered together, slide the pulled back heat shrink over the exposed wire and apply heat from a heat gun or a lighter like in the second photo.

Step 4: Sewing the Components Into the Beanie

At this point your circuit has been all soldered together based on the fritzing schematic. Try to double up on the sewing on the heavy components such as the audio adapter and battery. Techniques I used myself were crosses and sealing up the flap of the beanie all around. It's simple to redo or fix any mistakes made in the circuit later on because the thread is thin enough to cut and re-sew later. It's especially good if you use a yarn hat like I did so you can sew through the holes in the knitting as a guide. At the end the sewing should look something like my Toasty Tunes in the picture above. Thanks for reading this guide and best of luck with your future makes.

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