Instructables

Build a Bluetooth Intercom for bike rides, motorcycle rides, espionage, general mayhem, etc...

In this instructable I'll show you how to build a wireless intercom for short-range two-way communication. You can use this to chat with another person on a bike ride, or on motorcycle rides with helmet-mounted bluetooth headsets (that's my next instructable.), all while sharing your music or podcast (from iPod, cd player, etc.) This one is almost too simple for me to take credit for, since I'm really just repurposing a bunch of things and just making a very simple adapter to make them work together. That's good news for you though, because that means it's very simple, and though it's unlikely that you'll have everything just laying around, at least some of you will have a couple of bluetooth headsets handy.

Step 1: Buy some stuff.

So you'll need a few things for this, first you'll need to search eBay for "Motorcycle Intercom". Amongst all of the really good (and expensive) intercom systems, you'll find the very inexpensive (usually around $25.00 shipped) wired intercom systems that use standard 2.5mm cellphone headsets. These can probably be used for other things, so don't throw them away, but put them aside. We wont be needing them.

Next we need the Jabra A210s (or any bluetooth to 2.5mm wired adapter). I found these cheap ($20 each) at cell Xpo, link, so I used them over the Cardos, which were about $50.00 each. These will plug into the motorcycle intercom module where the wired headsets would have plugged in. See what we're doing here?

In my intro page, I mentioned that very basic soldering is required, but if you get one of the el cheapo intercom systems and find that the connectors are 2.5mm, you actually wont need to do any soldering at all. Mine is actually different from the ones most commonly found on eBay, and had 3.5mm jacks, so I needed to adapt the 2.5mm jacks to the 3.5mm ones on the intercom.

Lastly, you'll need to buy a couple of standard Bluetooth headsets. If you're in the states you're in luck. Recent legislation in my home state of California has required that anyone using the phone while driving do so with a handsfree kit, which means a bunch of online retailers are making great deals on Bluetooth headsets. I got a two pack on buy.com for $20.00.
 
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pmdulaney1 year ago
This sounds like a great idea for cycling with friends, but I'm concerned about the range. Mr Lordgarion514 quotes an area of 250,000 sqft, which works out (area= pi*r^2) to a radius of 282 feet, which is pretty good. But just this week I bought a little Bluetooth enabled speaker from Radio Shack. I had to return it because I couldn't get good reception between my study (where my Mac is) and my bedroom, no more than 20 feet away. Are there different classes of Bluetooth devices -- for example, high power vs low power? Or can someone who has built one of these setups say what kind of range he or she gets?
OK, in answer to my own question, there are 3 classes of Bluetooth devices:
Class 1 - 100 mW - ~100 m range
Class 2 - 2.5 mW - ~ 10 m range
Class 3 - 1.0 mW - ~ 1 m range
So hopefully we're talking about a Class 1 device here.
NikoSilver1 year ago
How about linking the two A210s directly to one another? (maybe using smthng like this: http://www.google.gr/imgres?start=293&hl=en&sa=X&tbo=d&biw=1552&bih=917&tbm=isch&tbnid=2Gn7ASBWeJt6pM:&imgrefurl=http://hydrophones.blogspot.com/2009_01_01_archive.html&docid=j739ws3bnP4iWM&imgurl=http://1.bp.blogspot.com/-DsLASneX1N0/T-thPPlr2hI/AAAAAAAAHOE/8gaepEHar54/s1600/6a084771a87bcb653358e337b7e5d50b.jpg&w=856&h=428&ei=r7_lUJgsopvRBYyNgegC&zoom=1&iact=hc&vpx=317&vpy=647&dur=4269&hovh=159&hovw=318&tx=231&ty=97&sig=117478213163572293690&page=7&tbnh=146&tbnw=263&ndsp=55&ved=1t:429,r:32,s:300,i:100 )
Just found this while bouncing around the site.
It's amazing what a little bit of time does to things.
Dragon now has a Bluetooth headset called callpod V2. You can find them under 20 bucks with free shipping(got mine from wally world for 9.97 with free shipping to the store). They let you connect 2 of them together just like you would connect 1 to a cell phone. Advert says when 2 are paired together they work over a 250,000 square foot are(I assume this would be a circular pattern). Not sure how far apart that works out to but should be plenty to use for this.
robots1996 years ago
I just use a helmet with speakers in it but maybe I can do this project and put the bluetooth headset's circutry into the helmet! I will be right back........
Still waiting... LOL
How do you sync the headsets to the Jabras?
How to pair the Jabra a210
http://www.ehow.com/way_5263653_jabra-instructions.html

It's simple
stuffman (author)  CorillianAle6 years ago
There is a pinhole on the bottom of the Jabra, which puts the device in pairing mode. It's pretty easy if you've ever paired a BT device before.
ivancamilov3 years ago
I'm there with CorillianAle, It's not very clear to me how you sync the Jabras to the headsets. Usually when I pair a new BT headset to my phone, I have to go to my phone's bluetooth preference panel and choose the headset. Sometimes, you need to enter a PIN (0000 or 1111 are the most common).

Could you elaborate on that, please? thanks a lot! :)
There's no PIN to enter. The bluetooth signal goes from the headset to the Jabra adapter. You just press a pairing button..
http://www.ehow.com/way_5263653_jabra-instructions.html
The adapters are cool because you can plug them into your home cordless phone, mp3, cd, tape player, etc... and go wireless.. up to 20-30 feet that is.
abadfart3 years ago
I would have to say to crack open the head set and put on a throat mic on and a nice ear bud
frenkstayl3 years ago
Nice blog!!!!!!!!!!Really a great knowledge about different thing about interim.I refer my friend to this site for more information.They also impressed by this site.Sena SMH10
fannylee3 years ago
it is reli a great idea to build a unique one myself, but it is a bit troublesome for a girl..I recommend a highest performance to price ratio Bluetooth Helmet Headset - BlueWhale G8. Explore more features on www.BlueWhaleIntercom.com.
fjr_scoot4 years ago
Shawn, Great idea! I have one of the intercom/amplifier units with 3.5 mm jacks. There are 3.5mm Audio Bluetooth Adapters for MP3's available on eBay. Pardon my ignorance, but would 3.5mm Audio Bluetooth Adapters for MP3's work with this, or would I need a Bluetooth Adapters specifically made for use with phones? thanks!
I found this article in persuit of trying to find a way to do what you did except with Stereo instead of mono audio. I was hoping you might have some ideas. I have been searching for a dongle like the jabra that also handles stereo with no success. I was thinking that this could also be done using two seperate dongles, one to transmit stereo signal and a seperate for the intercome, but this seems more complicated and should be able to be done with one unit. another idea would be to build a repeater like the bluecom 102 (http://www.ake-electronic.de/Service/Artikelinfo/BlueCom102+BlueComfor2-en.pdf) but don't know how difficult that would be or where to get the electronics. Thanks for your thoughts.
thebfs4 years ago
I have same problem as sholson radio shack adapters dont work.
any one know of a specific one that does?
sholson5 years ago
I built a system as you described with your instructions. After assembling the project, I purchased a Radio Shack 2.5 to 3.5 adapter. The unit would work properly using the headphones that came with intercom, but would not work using the bluetooth earphones. I am sure they are paired and checked the pairing on my computer. You mentioned "an amplifier" would be necessary. Where do I do from here to make the system work properly. Thanks
Could you not simply hotglue a piece of microphone foam over the hole to cut down the wind or perhaps something similar like the material used in the pop reducer screens for recording mics? or maybe a snippet of nylon stocking?
Tgrshaw6 years ago
Why not eliminate the "motorcycle intercom" gadget($$$). Use a couple of 2.5 mini-jacks... wire the output of one bluetooth adapter to the input of the other and vice-versa for the other one. 2 jacks, 3 wires, a piece of heat-shrink... 5 minutes with a soldering iron. Of course you wouldn't have the "tunes" option.
xavanty Tgrshaw5 years ago
make a Instructable of this I iressing in it
stuffman (author)  Tgrshaw6 years ago
...Well I'm glad I'm not the only one who had this idea! This was my original plan, it seemed so simple, but as it turns out, amplification is necessary to get the two devices to talk to each other. Luckily I could still use the 2.5mm jacks that I used to join the two boxes to make my adapter cables. Shawn