In this Instructable I will show you how I have built my wireless bicycle mounted Bluetooth speaker. I have to say, this might be one of my favorite projects so far. It looks great, has great sound and has that futuristic appearance! As always, I will include the build plans, laser-cut plans, the wiring diagram and of course the list of the parts and tools that were used in this build. Make sure to watch my YouTube video first and then come back for further details of the build. Let’s dig in!
Step 1: Components and Plans
Make sure to check out the wiring diagram and all the plans included if you would like to build a speaker like this one yourself! Feel free to download it and zoom in for a better view.
- Coaxial Speakers - https://ebay.to/2WLS6gn
- TDA7498E Class D Amplifier - https://ebay.to/2SvlwzT
- KCX BT002 Bluetooth Audio Reiceiver - https://ebay.to/2Dh6ipK
- 150W Boost Converter - https://ebay.to/2QXdbAj
- Step Down Converter - https://ebay.to/2RTwK0Z
- Isolated Converter - https://ebay.to/2TTBhxE
- 3S LED Battery Capacity Indicator - https://ebay.to/2szdRCj
- 2mm Blue LED - https://ebay.to/2FAxhiE
- 22mm Latching LED Switch - https://ebay.to/2JyPnB9
- 12.6V Battery Charger - https://ebay.to/2D6jXAm
- Waterproof DC Input Jack - https://ebay.to/30jk97D
- 3S Battery Management System Board - https://ebay.to/2AV4elI
- 6 x NCR18650B 3400mAh Lithium Ion Battery - https://ebay.to/2swviDm
- M2.3 x 12mm Self Tapping Screws - https://ebay.to/2RDrUFG
- Single Sided Adhesive Foam Strip - https://ebay.to/2SXcpFf
- Velcro Straps - https://ebay.to/2XUlbcE
- Adhesive Foam for Protection - https://ebay.to/2RZ4EkM
TOOLS and MATERIALS:
- Wire Stripper - https://ebay.to/2G4x9av
- Multimeter - https://ebay.to/2GrYP9x
- Hole Saw Kit - https://ebay.to/2Wix3RY
- Center Punch - https://ebay.to/2ZJSU6N
- Hot Glue Gun - https://ebay.to/2F3bhZ5
- Sanding Sponge - https://ebay.to/2TuJhW9
- Epoxy Glue - https://ebay.to/2DtAtvk
- Jig Saw - https://ebay.to/2M4yNMF
- Drill - https://ebay.to/2JweCno
- Soldering Iron - https://ebay.to/2yYfbSF
- Solder - https://ebay.to/2S5akaD
- Soldering Stand - https://ebay.to/2HH4nOg
- Drill Bits - https://ebay.to/2HGpi4b
Step 2: Important to Notice!
Even though it is self-explanatory it is worth mentioning that everyone’s enclosure’s size and shape will depend on the bike frame that you have. Therefore make sure you check that the enclosure will not obstruct any movement of the pedals and cranks or the suspension components if you have a full suspension bike. To do that you can simply cut a few pieces of cardboard in a shape of the speaker enclosure and check the fitment and cut the cardboard accordingly to achieve a great fit.
Therefore I am only including a picture of my enclosure's build plans so that you can get an idea of how the parts should look. Notice that some panels have an angled cut so that they fit nicely along each other.
Step 3: Building the Enclosure
For the main building material I chose 12mm MDF which I love working with. It is sturdy, strong and can be painted over with not much effort.
I used the tablesaw and a jigsaw to cut the pieces to required dimensions. I sanded the edges to achieve the necessary angles for the box to be glued without blank spaces.
To cut out the circles for the speakers I used a wood router with a circle jig. You can also use a jigsaw for that manner since the edges do not need to be perfect because the speaker will be mounted on top. I also used a combination of router bits for the plywood panel to sit flush with the surface of the speaker.
Step 4: Glue Up!
Healthy amounts of wood glue on the edges of the panels to ensure a strong bond between the pieces. Using a plastic card I spread the glue evenly along the edge. Make sure to use a square when gluing the panels together!
Step 5: Treating the Edges
Once the glue has dried, off camera I have glued in the support pieces for the side panel to be screwed in. I also sanded the sharp edges smooth and round. Using a roundover bit I ran across the outer edges of the enclosure making them round and smooth to the touch. A dust mask and dust collection must be used for this step which includes lots of MDF dust!
Step 6: Painting the Enclosure and Plywood Pieces
To paint the enclosure with the colour of choice, first of all we need to tackle the tricky nature of MDF panels which is its ability to absorb lots of liquid including paint that contatcs its surface. In order to achieve a nice paint finish on the MDF we need to create a thick layer or a coat that would not absorb the paint in to the pores. Since I could not source a simple sealant for MDF in my country, I went with a 50-50 mixture of water and Titebond III. I chose Titebond III since it is used for outdoor use and will not be penetrated by liquids. I simply mixed the two and brushed a thick coat of it on the MDF enclosure and then letting it thoroughly dry overnight.
Once the sealant has fully dried you can see that the surface is glossy and is actually really smooth to the touch. It is now ready for paint. Before our color coat we need to seal the panels with a thin coat of primer to smooth out the surface even more. Before spraying the primer I scuffed the enclosure’s surface with some 200-400 grit sandpaper.
While the primer was drying I sprayed the laser-cut plywood pieces with a few coats of clear lacquer to make the wood a bit resistant to outdoors.
Off camera I sprayed my colour of choice which is matte black on the enclosure once the primer has fully dried.
Step 7: Electronics!
I did include a wiring diagram in Step 1 for this build so make sure you take a look!
For the battery I used six 18650 Lithium Ion cells with a capacity of around 2700mAh connected in a 3S2P configuration. 3S means three batteries are connected in series resulting in a voltage of 12.6V. 2P means that there are two 3S packs wired in parallel, resulting in a battery pack with a voltage of 12.6V and a capacity of around 5.4Ah. That means that the battery will be able to provide nearly 50 Watts of power for over an hour!
The cells are connected to a BMS (Battery Management System) board which makes sure that all the cells are charged to the same voltage which is very important for the longevity and overall safety of the battery pack. I think this board is great since it has short-circuit, over charge and over discharge protection and even a temperature sensor! (I did not use it on this battery pack)
Just to play it safe, I stuck a piece of adhesive foam on the ends of the battery to protect it from any shorts. I also wrapped the contacts and the whole pack with kapton tape.
Then according to the wiring diagram I soldered all the connections and began putting the components inside the enclosure making sure to use plenty of hot glue to hold the components in place.
Step 8: Sealing the Enclosure
Super important step! Making sure to seal the enclosure so that no air escapes once the speaker is working. For that I used a single sided adhesive foam strip across the edges of the enclosure. I also applied glue around the switches, blue LED and ports that were mounted on the plywood control panel to make sure that the enclosure is air-tight.
Step 9: Mounting Hardware
To mount the speaker to the bicycle frame I used 4 velcro straps on the top of the enclosure and 2 straps on the bottom. For this build I made my own velcro straps which to my mind are better lasting and have a better grip to the bicycle frame. I also placed a strip of soft adhesive foam across the top and the bottom side of the enclosure to protect it from ant bumps in to the bike frame.
Step 10: Last Steps!
Just a few thing left to do to finish the speaker, such as screwing the control panel in place, gluing on the volume knob, placing sealant strip around the speaker holes, screwing the panel in place, placing the speakers and the grills on top of them.
Step 11: Final Thoughts
All that is left to do is screw the logo in place and we have the finished speaker! I am truly happy of how it turned out. It is tightly held in place with the velcro straps even though the speaker does weigh some. Since I finished this build in the middle of the winter, I did not have an opportunity to get outside to test this speaker while riding the bike. But strolling across one room to another it seems it would hold up well to riding. It takes a few hours to charge the speaker up. The Bluetooth 4.2 connectivity is amazing, the range is great even through a few walls around the apartment. You can also hear the voice prompts of the Bluetooth module letting you know when the module is connected to your device. And I have to say, the connection is instant as you can see in the video! It sounds great and is plenty loud for outdoor use.
Thank you for tuning in with me to this project! Hope you had fun and maybe learnt something new from this one! Make sure to take a look at my other projects and YouTube videos and I will see you on the next project!
Runner Up in the
Epilog X Contest