This Instructable details the hacking of an off-the-shelf Bluetooth speaker and flickering LED tea light to become the streaming front-end for your home theater system, while keeping the Bluetooth speaker's original functionality intact.
I was probably the only person on the planet without a Bluetooth speaker. Rectifying the situation was made easy by a colleague who spotted a great deal for the Canz 808 Bluetooth speaker. The speaker itself is surprisingly capable for something this small and a handsdown winner for portability, but I do like the sound produced by my home theater receiver a lot better. I have a smartphone capable of streaming whatever music I want, and a speaker that can connect wirelessly to my smartphone, and I'm still thinking..... "wouldn't it be great if this speaker had a line-out jack that I could plug into my home theater system?" A quick bit of googling came up with commercial products that would enable Bluetooth streaming to my home theater system for reasonable money. But, I already had the speaker and I don't need 2 different products. So I hacked the speaker apart to create a line-out connection to my home theater receiver. Now I can use the Bluetooth speaker either as small standalone speaker like the manufacturer intended, or connect it to my home theater system for those times when I need a little more wall rattling ooomph.
And it just feels like magic being able to change the music selection in real-time from the phone in your hand.
This is guaranteed to void your warranty! The modification is neatly concealed on the underside of the speaker so that the final hack looks like the original product.
Step 1: Stuff you'll need
Show All 9 Items
Even small projects require a largish amount of stuff. Here's my suggested list.
Step 2: Speaker dissasembly
To start, remove the rubber ring at the base of the speaker. It is glued in place by the manufacturer so just carefully pull it off. The rubber ring conceals the 3 screws that attach the base to the speaker. Remove these screws with a small phillips screwdriver and gently easy the black plastic base off. Be careful not to damage the wires for power+sound that attach the base to the speaker. No big deal if you do accidentally break something - just adds to the work you'll need to do!
There are two small screws that attach the PCB to the black base. Remove these screws to free the PCB as you will need access to the underside of the PCB later for wiring in the audio signal to the USB connector.
Step 3: Mounting the switch
The LED tealight has a small latching pushbutton switch that we need to disable the enclosed speaker when the bluetooth device is used as a streaming front end for the home theater receiver. First remove the battery from the LED light and then pry the base out. This is by no means a gentle operation but be careful not to accidentally rip the terminals off the switch.
The switch will be mounted to the Bluetooth PCB. One of the PCB holes will be sacrificed as shown in the picture. Enlarge the hole with the 3/16" drill bit so that the switch button fits though it. I used a small file to adjust the hole as needed.
Step 4: Wiring the switch
There is a black and a red wire that connects to the internal speaker. Using a pair of side cutters cut the red wire leaving enough wire on the speaker side (about and inch) so that you can solder an extension piece of wire to it. With the extension soldered, add a small piece of heatshrink or wrap vinyl electrical tape around it to insulate the connection.
Run the extension to the middle of the switch. Cut the extension wire long enough to reach the switch in the switches mounted position and ensure you have a little slack int he wire. Strip the wire that is still attached to the PCB and attach it to either of the remaining switch terminals. THe switch will be used to enable or diable the internal speaker. When streaming through the home theater system, you want the switch to disable the sound out of the Canz speaker. When used as a standalone Bluetooth speaker, the switch is used to enable the sound from the speaker module.
Now hot glue the switch into position. Minimise hot glue that extends past the edge of the PCB as this will need to be trimmed off to get the PCB back into the housing.
Step 5: Connecting the line-out
Cut two pieces of 28 or 26 gauge hookup wire about 2.3" long and strip and tin the ends. On the backside of the pcb, solder the wires to the positive and negative speaker connections as shown. Solder the other ends to the USB connector. The line out connection will utilize the USB D+ and D- pins which are unconnected on the PCB.
Step 6: Reassembly
Show All 7 Items
All the internal wiring work is done. To reassemble the Bluetooth speaker, you will need to make clearance in the housing for the latching pushbutton switch. The easiest way to do this is with a Dremel rotary tool and a metal burr attachment. Work at low enough speed that you don't melt the plastic and be careful not to slip and damage the battery.
We sacrificed one of the base mounting screw positions for the switch. Now drill out the mounting hole with the 3/16" drill bit and test for fit. You may need to make some small adjustments to get everything lined up properly. I used a small round file for this.
Reassemble the PCB to the base and then screw the base to the speaker. Punch a hole in the rubber ring to lineup with the switch and glue the rubber ring back to the speaker using a touch of contact adhesive if necessary.
Step 7: Line-out Cable
Show All 12 Items
The cable has a dual purpose. One end is used for charging the speaker, the other end is the line-out connection for your home theater receiver.
First cut the supplied USB cable connector off at about 3 inches from the back of the connector. Strip and tin the wire ends with solder. This needs to be done on the USB A and B connector sides. ON the A side, we don't need the Green and White wire as these now carry audio for the mini-B connector. Insulate the ends of these 2 wires so that they are electrically isolated from the cable. Make sure not to create a short circuit.
Cut the RCA connectors off one end of the cable. I normally cut so that I have enough cable left so that the connectors are usable on future projects. Strip and tin the wire and then connect the two grounds together and the 2 signal wires together. The output of the speaker is mono and the home theater receiver input is stereo so we feed the same signal into the left and right terminals of the home theater receiver.
Now solder everything as follows:
Before soldering, cut heatshrink as needed to insulate the connections after soldering. To give overall strength, a heatshrinked a couple of pieces over the entire connection area of the cable.
Step 8: Test and enjoy
Using the freshly installed switch on the base of the speaker to turn the internal speaker output off, plug your new combination cable RCA ends into an available Audio input on the rear of your home theater receiver. I had CD inputs available so that is what I used. If you have AUX inputs available, that will work fine. Connect your smartphone via bluetooth and you should be able to hear the sound output from your home theater receiver. I set the home theater volume about 1/3 up and then use the smartphone to adjust volume remotely using the volume controls on the smartphone. This works out well for most my listening needs.
So if you got an unexpected bluetooth speaker as a gift for the holidays, you now have options to increase it's utility. Enjoy!