Filed under: Features
Today's How-To shows that with a
little ingenious wiring, a pair of
headphones
can become a pair of low-power rechargeable wireless speakers. For this
mod you will need:
- One or more wireless headphone sets with rechargeable bases (we used inexpensive Sony RF headphones)
- A soldering iron
- Two channel socket and plug connectors for power
- A miniature slider
switch
- Some thin cabling
- Plexiglas and hot glue or other material to build speaker
housings
- A dremel or similar to make openings in the speaker housings
If your artsy
friends have been begging you to build them wireless speakers on the cheap for their
Burning Man installation, read on. If not, it's still a
helluva lot of fun, so read on anyway!
First open the recharging
base of the wireless headphone set. Our unit had five screws underneath.
Unscrew the
circuit board from the back of the unit.
Solder two wires to the circuit board
where the recharging wires connect. These two wires are those which you have already soldered to the male end of your
socket and plug connectors. This will serve as the power for the rechargeable batteries as we will be destroying the
headphone housing to build the speakers.
File
a notch in the base to accommodate the charging plug's wires with a dremel or file. Replace the circuit board and close
the charging base with the screws you removed earlier.
Step 2: Choose a Speaker Set-upNext, for the headphone to speaker mod, there are several
choices.
1. You may choose to have both left and right speakers in one housing with all of the charging
circuits and batteries. (This example is pictured below:)
2. Perhaps you want the speakers to be
separate, but cabled between left and right. Half of the circuitry can be placed in one housing, half in the other. (In
the example pictured below only one speaker of the two has been completed, the other will hold the loose driver and
radio circuitry:)
3. You may want two separate left and right channels in separate housings with separate
batteries and circuitry. For this example you will need two sets of headphones. You may choose to place two sets of
drivers in each channel's housing. (This example not pictured because it is the same as Example 1 except there are two
speakers instead of one.)
4. Maybe your Burning Man friends are putting on the pressure for multichannel
audio in your mod. In this case, you can buy six sets of the
Sony headphones. The Sony model of cheapest RF headphones
has a selector for three different radio channels on the back of the base. In theory this means you can send three sets
of stereo which equals six unique channels of wireless audio out. (See drawing below:)
Step 3: Modding the Headphones into SpeakersTake apart the
headphones by unscrewing all the screws and popping open the housing. Try to keep the cables between the two sides of
the headphones intact. If you need to cut the cables to remove all the circuitry, simply do so and resolder the
connections later. Cut the battery housing down around the batteries with a dremel or small plastic cutting saw but
keep it intact as well. Create a small plastic box from Plexiglas and first cut a hole large enough to access the
batteries. First pictured below is Example 1 with both drivers in the same housing, then Example 2 with one driver in
each housing:
Cut a
small rectangular hole out of the housing for an on/off switch. This needed to be soldered in place of the spring-based
momentary switch in the headphones we used. Our headphone model turned on when the inside band of the headphones were
pulled by the shape of the wearer's head. We replaced this with a sliding switch which we then glued into the
housing:
Next cut a hole in the Plexiglas box large enough for the speaker housing. Remember that the speaker should be fairly
well sealed for resonance purposes. Viewed from the inside, the speaker glued on the hole looks like this, below:
Now solder the other end of the power
connector (the female end that fits the connector on the wire now sticking out of the charging base) to wire. Solder
the two wires of the power cable to the charging tabs that were in the headphone housing. These tabs were the ones that
came in contact with the charging springs when the headphones were placed on the charging base. Two views of the power
connector (ours in this case is large and white in the photos) follow showing the tabs where the wires were
soldered.
Now test
your speaker(s) with your system's base with audio to make sure you haven't forgotten anything. Repeat the steps above
for each speaker in your system. You may want to glue down the channel selector dials on the speaker side if you decide
to go the multichannel route. Also the volume dial on our sets have been glued to maximum for applications where the
speakers are in a public setting. Alternately you may wish to cut rectangular holes in your speaker housing to access
the volume and RF channel selection potentiometers.
Some other further development for you electrical
engineering types can include creating audio outputs for better speakers and gain stages instead of speakers on the
receiving end. Be creative! This How-To is by no means meant to be a finished creative entity.
Leave us
feedback if you send some of these bad boys up in balloons in the high desert.
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