In a noisy environment, (such as a bicycle or an old car on the highway) bluetooth headsets do not work well. Why? Because the microphone is so far away from your mouth that it would just as soon pick up the road or wind noise as your voice. No amount of "advanced voice technology" can get around that simple truth. Since I ride my bike to work, drive a 1971 Volkswagen Squareback and a 1983 Toyota pickup, road and wind noise is a problem for me. I also like to keep both hands available for driving/biking tasks instead of holding a phone against my head. I haven't seen any bluetooth headsets with a boom for several years now. It seems manufacturers are trying to keep them small. That is fine in a quiet environment. (a late model Lexus, maybe?) I don't have that luxury, so I decided to add a boom to my headset.
Step 1: Bust It. (or, How Badly Do You Want Better Sound?)
This is the part where you take your $30-$150 headset and break it. If you spent an amount closer to the $150 side than the $30 side, you should skip this and buy a Lexus. I have been using this headset for over 2 years now, and was ready for it to be better and uglier, so it was an easy choice for me. I have been taking apart small electronics ever since I could turn a screwdriver. That didn't help me here. I can't speak for any other headsets, but mine had no screws at all. The two halves were glued together with a plastic welding glue. I just had to shove a screwdriver in there and bust it apart. Not pretty. When wedging your small screwdriver in there, be careful not to pry too hard against anything inside. I managed to get mine apart without damaging the batteries or circuit board, but the casing was pretty well destroyed. If I had it to do over again, maybe I'd be able to do it cleaner.
Step 2: Cut the Boom
I used a Papermate pen tube for the microphone boom. Any small tube would work. The Papermate may not be the best solution, as I haven't found a glue yet that effectively sticks to it. Bic pens seem to have a softer plastic that may work better for the glue, but they are a straight cylinder, and are usually white. The aesthetics of that may or may not be desirable. After cutting the tube to your desired length, (based on the size of your face, or preference) make a hole for the microphone to sit in. I used a side-cutting bit on my dremel to carve it out. That was a little difficult to control. Perhaps a small round file would do the trick, or even just a pocket knife.
Step 3: Shape the Boom Recepticle
Next we need to make a place to put the boom in the headset housing. For this I again used the side-cutting tool in my Dremel. Carve a half circle out of the top, and a half circle out of the bottom. In order to angle the boom towards your mouth, hold the dremel at the angle you want the boom to go while cutting.
Step 4: Add Microphone Wires
Unsolder the microphone wires from the circuit board. Take note of which color wire went into which spot on the circuit board. Cut some wire to the correct length to extend the original microphone wires long enough to reach the end of the boom. Solder the extension wires to the original microphone wires. Cover the solder point with heat-shrink tubing or electrical tape. Twist the wires if you choose.
Step 5: Thread Wires and Solder
Stick the long wires that you soldered onto the microphone into the hole you made for the microphone at the end of the boom. Thread them out the end of the boom that goes into the headset. Route the wires as similarly as you can to the route the original microphone wires took. This should avoid obstructions when reassembling the headset. Solder the extension wires to the original microphone wire's locations on the circuit board. Try to maintain the original polarity, though I'm not sure how much that really matters. A passive microphone should "microphone-ify" (generate electrical impulses that represent the pattern of sound vibrations) in either direction.
Step 6: Start Gluing
Adhere the boom to one half of the headset. I used super-glue ( cyanoacrylate ) first. It didn't stick to the Papermate pen tube. Then I tried hot-glue. It also faired poorly with the pen tube. In the end I used plastic epoxy. It still didn't stick to the pen tube, but is more rigid when cured, so formed a sort of ferule around the boom to add stability. When gluing the two halves of the headset back together, make sure any electrical contacts between the halves are unobstructed. Note where the earphone contacts are on my circuit board. I had some trouble keeping the microphone extension wires out of the way. To hold the microphone in the hole at the end of the boom, fill the hole with hot glue and position the microphone facing towards where your mouth will be when using the headset.
Step 7: Finished, and Thoughts.
Once it is all glued together, allow all the glue to cure. The boom will be very sensitive to breakage at the headset. Especially so if you used a Papermate pen as I did. If I were to do this project over again, I would select a different material for the boom. Perhaps a Bic pen tube or some other type of plastic to which glue more readily adheres. Despite the fragility of the boom, I am very glad that I added it. It has made a world of difference in the functionality of the headset. Before when I was driving my truck any faster than 25 mph I had to shout to be heard. When I received a phone call on my bicycle, I had to give up trying to continue riding, or just not answer the phone. (wouldn't that be a tragedy?) Now people have no trouble at all hearing me in the truck. Today when my wife called me, she didn't even know I was riding my bike, except that I was breathing rather heavier than normal. The effectiveness of the boom has well proven itself to me. Also, I would like to see more headsets be this large. It discourages leaving it on your face when not in use, as it looks rather silly. (normal bluetooth headsets look rather silly sitting on a person's ear when not in use, but this one does so in a bigger manner) Also, the act of pulling out and attaching this large headset should lead to less frequent interactions in the grocery store inadvertently engaging the entire line in conversation.