This project describes the steps involved to construct a working Bluetooth handset in the shape of a banana.
The premise is to permanently embed a Bluetooth headset inside of a fake banana, while exposing the necessary sound holes and USB port for in-place charging.
In practice, it took some time and patience to place the headset such that it remained functional inside of the banana.
One thing I would do differently would be to extend the length of the microphone wires so that I could increase the distance between the earphone and the microphone, and to insert some sonic insulation between the earphone and the microphone, as my finished banana phone gives a terrific echo back down the line to the remote party.
I apologize for the low quality of my photos. I recently "bricked" my digital camera by leaving it outside in my vehicle during some of Nebraska's coldest days. The photos in the instructable were taken using the camera in my LG Chocolate phone.
This project was inspired by the DIY Banana Phone at Make Magazine, as well as the Bananaphone song by Raffi and remake by Rhonda Vincent.
Step 1: Gather Your Tools, Banana and Bluetooth Headset
You will need the following tools and components:
Banana - found Michael's craft store
Small drill bit
Fast setting epoxy glue
Electrical tape or heat shrink tubing
Small diameter translucent plastic straw, tube, or rod
Step 2: Hollow Out the Banana
Carefully use the X-Acto knife to cut out an access panel in the banana. You will be doing all of your work through this hole, so be sure to make it big enough to allow the Bluetooth headset and your tools to pass through it. However, keep it as small as you can to minimize the impact on the finished product.
Use the tweezers to hollow out a cavity to hold the headset. My banana appeared to be made of compressed styrofoam balls inside of a realistic looking plastic skin.
Surprisingly I found a chunk of cement (concrete) in the banana. I presume it's to give the banana the proper weight and balance. Unfortunately, the cement was exactly where I had planned on placing my headset, so I had to shift the focus of my efforts to the upper part of the banana.
I considered digging out from around the cement to remove it, but I had no way to tell how long the piece was, plus it may provide crucial structural support for the banana.
Also take a moment to make a paper or cardboard template of the circuit board. This will help you line up the USB port hole and sound holes for the earphone and microphone.
Step 3: Make Earphone Holes.
Use the X-Acto knife to start a pilot hole. Follow with a small drill bit twisted by hand to make a set of nice, finished holes. The banana should be hollow behind the skin where you place the hole.
Step 4: Extend the Length of the Earphone Wires
The supplied wires from the circuit board to the earphone are very short. Extend the wires so that you may position the earphone where ever you want inside the banana.
Use wire cutters to cut the wires. Cut a small two-conductor wire extension. Use the wire strippers to remove a small bit of insulation from the wires. Solder in the extension and wrap with electrical tape or heat shrink tubing.
You might also take this opportunity to loosen up the hold of the USB port. Do this by taking your knife of small screwdriver and bending up the tab on the top of the USB port. This will reduce the amount of force necessary to plug and unplug the USB charger.
Step 5: Glue the Earphone Into Position
Fashion a gasket out of a length of wire. The idea is to offset the surface of the earphone from the surface of the banana run a bead of blue around the gasket. This will secure the earphone into position but allow a space between the speaker and the wall of the banana.
Use epoxy glue to secure the earphone speaker to the inside of the banana wall opposite the holes drilled previously.
Step 6: Expose the USB Port for Charging the Headset
Make a small hole near where the USB port will be exposed through the skin of the banana. Pass through a length of wire so that it comes out through your access panel opening.
Take the end of the wire coming through your access panel opening and pass it through an opening in the USB port and twist the wire back on itself. The idea is to make a firm mechanical connection so that you can draw the USB port firmly against the inside of the skin of the banana at the point where the port will be exposed.
Use your X-Acto knife to trim the opening to fit the USB port. Carefully apply some epoxy glue to secure the USB port into place. Be sure not to get epoxy in the USB connector itself.
Apply epoxy glue to the other end of the headset circuit board to anchor the board in place at both ends.
Cut and remove the draw wire after the epoxy has set.
Step 7: Create Button on Outside of Banana
The purpose of this step is to create a button that will allow you to press the circuit board mounted button from the outside of the banana. Additionally, if the button is close enough to the surface mounted LED on the board, the button will conduct the light as well, creating the impression that the button itself is lighted.
The flashing of the blue LED on the banana is impressive and goes a long way to reinforcing the idea that the banana really is a Bluetooth device.
I was lucky enough to have on hand some translucent tubing that was perfect for channeling the light and serving as a rod to actuate the button on the circuit board. The tubing is from the stick of a sucker that was part of a Valentine's Day bouquet of candy flowers I received from my wife.
Using your paper template of the printed circuit board, try to figure out where the switch and LED are underneath the skin of the banana. Use your knife and drill bit to make hole above the switch. Cut the tubing to the necessary length and insert it into the hole.
Honestly, I have a hard time actuating the switch using the tubing, so answering the phone by pushing the button is difficult. If you can find a way to keep the tubing on the switch, you may have better luck. Perhaps a dab of silicone glue would do the trick.
Step 8: Glue the Microphone Into Position and Close It All Up
Glue the microphone into position using the epoxy glue. If you can, insert some kind of acoustic insulation or a barrier between the earphone and the microphone to minimize feedback.
Glue the access panel back into position.
Now be sure to visit populated locations and take calls on your banana phone.