Intro: A Solid Diy Bluetooth Speaker
Hello everybody. This instructables is for anyone who wants to make themselves a hand sized portable bluetooth speaker, which sounds really fine. I've been making speakers myself for approx. 7 years and ever since I came up with this model, I wanted to share how to make it. This is the time :)
For the ease of assembly, I've made a kit. It contains all the parts needed to create a speaker, except the rechargeable battery. Due to the laws of my country, I can not ship it. However, the 18650 battery is widely available. If you don't have a possibility to get one at a local electronics store, you can buy one here.
Before we start the build, here are some specs and notes about the speaker:
10W of power
8 hour plus battery
custom dsp equalised sound
water resistant drivers and passive
Worth to mention:
the speaker is DSP equalized, meaning that it has no distortion whatsoever and has a frequency response range from 65Hz to 20kHz, which is quite impressive since the enclosure is not big at all.
the electronics are precisely chosen to work together which means no background buzz/noise and an outstanding battery life since they are very efficient.
the bluetooth is 4.2 and has aptx which ensures that audio that's transmitted through bluetooth is as clear and crisp as if it was sent through a cable.
So, let's start building it!
Step 1: Make an Enclosure
We start by making the enclosure.
The wooden pieces you see in photos can be found in the kits that I have available on aukits.com. They are laser cut from 4 mm thick Mahogany wood but you can make your own enclosure from anything that's sturdy enough (I have the laser cutting files on the website). If you were to make your own enclosure, just follow the same steps as there are only a few key things to look after.
1. We have to glue the separate pieces (1st photo) to a box. Use super glue gel, since regular superglue soaks into the wood and doesn't stick anymore. When putting the glue on, make sure to do so in a single line (2nd photo), since this will help the enclosure to be more air tight, which is necessary for it to sound good.
2. When attaching the back panel (the one with the holes for switch, led, mic, charging), make sure to do so in little dots (3rd photo), as we will have to detach it later.
3. After letting the glue set for some time, I suggest sanding the enclosure though you can leave it as is and go to Step 2. So, start sanding it. 150 grit sandpaper works just fine. I usually use a board with sandpaper glued on top (4th photo), which results in a more uniform surface of the mahogany (5th photo), though it is totally fine to sand with just regular roll of sandpaper. Make sure to sand the surfaces which don't contain the black rims as well, just to make it more smooth (6th photo). Lastly, round over the edges (7th photo) to make it more comfortable to hold, but this is completely optional since some people might prefer a more boxy look.
That's all for making the enclosure!
Step 2: Add a Finish
The next step is to add some sort of a finish. We do this since:
- the wood has lost some of its colors due to sanding (1st photo)
- lacquer protects the surface and makes the speaker more airtight
1. Choose your type of finish. I use glossy spray lacquer (2nd photo) as it makes the wood reflect the light a bit more and is easy to apply uniformly. You can use a matte lacquer if you want your speaker to have a more "calm" look.
2. Apply the lacquer (3rd photo).
3. Wait for the specified time.
4. Apply a second coat.
Now we can move on to the next step :)
Step 3: Prepare for Soldering
1. Open the back panel by sticking something sharp and slim as a scalpel knife along the edge of the back panel (1st photo). This is where the tiny glue dots pay off :)
2. Cut some material off the place where the charging module has to go as most micro usb cable connectors aren't long enough (2nd photo).
3. Attach the switch, led, charging module and the mic to the back panel with superglue (3rd photo).
4. Attach the rest of the electronics (4th photo) to the back panel with some rubbery glue. This ensures that parts can't vibrate too much and won't detach in the future. Do not use hot glue for any of these as they are heat sensitive.
5. Get some thin wire and flux (5th photo). Flux is not necessary but it makes soldering way way easier. I recommend putting some viscous flux in a bottle with a needle nose, which is helpful when soldering tiny, delicate parts. These bottles can be found in almost every vape/e-cigarette shop.
Step 4: Connect Electronics Together
1. Keep the switch in the turned off position and start by soldering the parts as shown in the 1st photo. Pay extra attention to not overheat the parts and make everything tidy and clean (2nd photo). Though not necessary, it is easier to identify the problem later if something is not working properly.
2. This is a crucial moment as if anything was connected to the dc-dc booster's output terminals when turning the switch on and adjusting the voltage, it could result in damaged parts! So, make sure nothing is connected to the output pads. Then turn on the switch, change the output voltage of the dc-dc boost module to 6.5 V (3rd photo) by rotating the little brass screw on the board. This is required for the amp to work at its optimal power.
3. After changing the output voltage to 6.5 V, turn off the switch and continue to solder the parts as shown in the 4th photo. Your parts should look something like this (5th photo) before being connected to the speaker drivers.
Step 5: Make Electronics Air Tight
At this step we need to fill the areas where air can get out with hot glue. The glue will cover some parts fully so this is a good time to check if everything works fine. (1st photo). You can connect the amp to the speaker drivers temporarily and when the switch is turned on, connect to the speaker with bluetooth. If the speaker works as expected, move on. If not, go through the electronics and check your connections.
1. Cover the areas with tape where glue can get in and damage the parts. For example, if the glue was to get in the switch, it would be impossible to move it. Same goes for the charging module's holes. (2-5 photos).
2. Use a generous amount of hot glue on these parts, but make sure no glue gets on the rim of the back panel because then it wouldn't attach cleanly to the rest of the enclosure (6th photo).
3. After the glue has cooled down, try blowing through each opening and listen if any air moves (7th photo). It should not.
Next step :)
Step 6: Mount the Drivers
1. Use a small amount of superglue to attach the speaker drivers to the enclosure (1st photo).
2. Lay a continuous line of superglue on the passive radiator's rim (2nd photo) and press it into place (3rd photo).
3. Now put some rubbery type glue around the drivers. This is, once again, to make everything air tight (4-5 photos).
4. Leave it to set
Step 7: Close Up the Enclosure
1. Solder the wires from the amp to the drivers permanently (1st photo).
2. Put a line of slow setting glue along the perimeter of the enclosure (2nd photo).
3. Put the back panel on (3rd photo).
4. Clamp the speaker down (4th photo). Be sure not to use too much pressure as that could bend the back panel and create openings along the outside edge!
5. Clean of the glue that has escaped (5th photo).
6. Leave it to set overnight and attach the rubber feet.
7. Enjoy, you're done! :)