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  • a cheap way to add bluetooth to anything

    Alright, just found a way to add bluetooth that really works well. The sound quality is great, with no apparent degradation (but my speakers aren't super revealing, either) and with this method, the bluetooth automatically recognizes most devices that try to connect with it, and requires no button to be pushed to pair anything up, etc.

    edit - thanks dainrobert, good reminder. here is a rough sketch anyway:Click image for larger version

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    First, buy one of those $4 bluetooth modules on ebay, like this one: link

    Next, pick up an adjustable voltage regulator, like this one, for about a dollar, depending on where you buy or how many you buy: link

    Then pick up a 5v DC isolator, like this one: link

    Before connecting anything, first wire up the adjustable voltage regulator to the + and - of whatever your power source is- I am assuming you will be integrating this with an amp, so 12v-24vdc power source most likely- and measure the voltage output with a multimeter. You can get a working, decent multimeter at harborfreight for a few dollars (amazing deal) or online. (alternatively, there are regulators you can buy which display the regulated voltage, cutting the multimeter out of the picture, and they are also very cheap and can be found on ebay). So then, measure the voltage output of the regulator, and adjust it (a tiny brass screw on one of the board components) quite a bit until the output is right at 5v. now that you have that part out of the way... wire the output of the regulator to the input of the isolator, and the output of the isolator to the input of the bluetooth module. Here is how to get at the bt module's input:

    First, you pull the USB bluetooth module apart (very easy) and clip off or tear off the usb plug portion, and solder a small wire to the '+5v' and the '-Ground' contacts on the small bluetooth board. This varies board-to-board, but if you study which part of a standard usb plug provides positive and which part provides negative, you can figure it out pretty easily. Worst-case-scenario is that you get it backwards, fry a board, and are out 4 bucks. If you are confused on what is what, take a picture and post in on here and someone will help ya. Attach the + and - from the bluetooth board to the output of the isolator. You may have to refer to a schematic of the isolator to figure out which of the pins are + and -, input and output. You can usually find the schematic online, but the isolators I ordered sometimes included a schematic.

    The total cost should be around 10 dollars, but could be as low as 6 or 7 if you buy items in sets of 10. The bluetooth chip produces a cool blue l.e.d. glow indicating that it is on, and is very tiny and easy to hide. The range is pretty good, at least 30ft.

    A few more notes: If you are simply adding this to a system and don't want to mess around with splicing into a power source, you can always just buy a 5v power adapter for a few bucks on ebay. You can even use the average cellphone charger, as long as it is the type that has a usb cable which plugs into the wall-wart and also into the phone, which is pretty standard... and then you can plug the usb bluetooth device into the charger and run a 3.5mm cable from the bluetooth module to the stereo- and walla.

    If you do integrate this into an amp, you can solder from the bt module (where it outputs to its 3.5mm jack) to a very inexpensive, yet high quality/positive feeling switch of this type: link

    You will have four wires running form the BT module to the switch: a L, R and ground wire, soldered from the 3.5mm output on the bt module, as well as the power wire which provides the board with its + voltage. This switch is an 'on-on', two-throw, four pole switch. This means that it is basically like four simple toggle switches all lined up and 'thrown' at the same time, and no matter what position it is in, position 1 or 2, something is being connected. I know this isn't gonna sound techy enough, but functionally, there are two sets of inputs and one set of outputs. You wire your bluetooth audio wires to a set of inputs, and your other amp input (say, your rca input or 3.5mm input) to the other set of inputs. Then from the output, you run wires to the amp itself or preamp, whatever you are running that receives your signal. On the switch, there are three rows, each having four pins. The outer two rows are the inputs and the central row is the output. Now, you could use only 3 pins per row and it would work, but I like integrating the bluetooth power also, so that when you flip the switch, the module comes on with it. So the extra set of pins just gives you one more built-in switch to use to activate the module.

    One area to possibly save cost and simplify is to use a simple 12v-5v dc to dc isolator to tap a preexisting power source int hat range. But most of those that I have found have been around 5$ and have had a specific input voltage range, so for this write-up I just recommend the adjustable regulator and add-on 5v isolator, for added flexibility of system incorporation.
    Last edited by arrayed; 12-29-2014, 06:21 PM.

  • #2
    Re: a cheap way to add bluetooth to anything

    You know the rules... WE WANT PICTURES!!!!

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    • #3
      Re: a cheap way to add bluetooth to anything

      If 12v is the source voltage, why no just use one of these?

      http://www.parts-express.com/bluetoo...2-vdc--320-351

      No soldering, voltage regulators or step down converters and far less connections. Even has RCA connections to go directly to many different receivers or amps. It also has circuity to reduce/eliminate EMI which can be an issue with lower cost 12v to 5v conversions.
      "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

      The Madeleine
      The Roxster
      Swopes 5.0
      Acoustic Panels
      Living Room Make Over

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      • #4
        Re: a cheap way to add bluetooth to anything

        The annoying thing with the Sure module is that it has a headphone amp onboard.
        A lot of 12v applications are portable audio. If you adjust gain to maximize output with mobile devices, the BT module will overload it.
        The other way around: the mobile device can't max out the amp.

        For home applications this is indeed an amazing value. Use an old phone charger as said and you added BT functionality for under 4 bucks.
        I've used a lot of those sticks, they're pretty amazing actually. Almost no noise, very cheap, small and good sound.

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        • #5
          Re: a cheap way to add bluetooth to anything

          Originally posted by Gordy View Post
          If 12v is the source voltage, why no just use one of these?

          http://www.parts-express.com/bluetoo...2-vdc--320-351

          No soldering, voltage regulators or step down converters and far less connections. Even has RCA connections to go directly to many different receivers or amps. It also has circuity to reduce/eliminate EMI which can be an issue with lower cost 12v to 5v conversions.
          Great point!!! I think there are a few issues with that board/suggestion though: First, the Sure bluetooth board costs 15 dollars more. Second, the reviews are a bit mixed, some people reporting that it does have EMI issues, which people have done various things to try and fix... and they have mentioned range issues (which may just be a result of how they mounted it) and third, the setup I mentioned does not have any EMI issues that I have run into, as it is truly isolated (at least as far as the 5v isolator is concerned).

          BUT... I really like the idea of using that Sure board, as some do report that it works great and is a true plug-n-play solution... and if mounted correctly etc... perhaps would be perfect for someone that didn't want to solder. So I think your recommendation is still a good one as a general bluetooth solution. And it is nice, like you say, to have RCA's right there etc... good suggestion.

          One key is getting the board mounted external to the speaker, or at least having the antenna portion near a vent etc... which I think helps out.

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          • #6
            Re: a cheap way to add bluetooth to anything

            Originally posted by arrayed View Post
            Second, the reviews are a bit mixed, some people reporting that it does have EMI issues, which people have done various things to try and fix... and they have mentioned range issues (which may just be a result of how they mounted it) and third, the setup I mentioned does not have any EMI issues that I have run into, as it is truly isolated (at least as far as the 5v isolator is concerned).

            BUT... I really like the idea of using that Sure board, as some do report that it works great and is a true plug-n-play solution... and if mounted correctly etc... perhaps would be perfect for someone that didn't want to solder. So I think your recommendation is still a good one as a general bluetooth solution. And it is nice, like you say, to have RCA's right there etc... good suggestion.

            One key is getting the board mounted external to the speaker, or at least having the antenna portion near a vent etc... which I think helps out.
            PE has only carried the Sure 4.0 model for a little over a month. I even purchased another unit this afternoon at 2:00 CST and they had 6 left. I checked a few min ago and they were down to one.

            If you look at the review dates they are older. The reason for this (and I am not sure why PE did this) is PE replaced the SKU, pic and description and kept the old reviews. The issues mentioned above were accurate in regards to the previous BT 2.1 unit.

            I have used the 4.0 units extensively. I was purchasing them from Sure in China before PE carried them. They do not exhibit any EMI as they have onboard isolated power supplies. I have mounted the directly next to speaker magnets and literally on top of Sure 2x8w amps in a stacked configuration.



            I can assure you that the reviews of the 4.0 module are not applicable to the current SKU. These units are so simple and bullet proof.

            I have used the eBay USB models before and the sound quality is noticeably different compared to the 4.0 unit. Infact I have one of the USB modules in my toolbox brand new that I would be happy to send you. Just send me a PM with your address. I love DIY, but I am also a sucker for simple.
            "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

            The Madeleine
            The Roxster
            Swopes 5.0
            Acoustic Panels
            Living Room Make Over

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            • #7
              Re: a cheap way to add bluetooth to anything

              Originally posted by Lutkeveld View Post
              The annoying thing with the Sure module is that it has a headphone amp onboard.
              A lot of 12v applications are portable audio. If you adjust gain to maximize output with mobile devices, the BT module will overload it.
              The other way around: the mobile device can't max out the amp.

              For home applications this is indeed an amazing value. Use an old phone charger as said and you added BT functionality for under 4 bucks.
              I've used a lot of those sticks, they're pretty amazing actually. Almost no noise, very cheap, small and good sound.

              This is true to an extent, it does boost the line level output signal. I use these with 2 different Sure amps, 2x8w and 2x15w, in portable boombox configurations. The 2x8w does have it's limit, but that limit is when the volume is almost at its max. The trade off is quick and solid connectivity and great sound quality at normal and moderate listening levels and single component installation. The overload levels I have experienced are at volumes that are almost unbearable. I have not experienced overloading of the 2x15w amp.

              I also have one in my 4runner and it goes directly into a 9 year old Alpine headunit. Works like a champ. I may sound like a work for them but I don't. I have had great luck with Sure products and their ease of connectivity and wire-up make them hard products to pass up.
              "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

              The Madeleine
              The Roxster
              Swopes 5.0
              Acoustic Panels
              Living Room Make Over

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              • #8
                Originally posted by GeralHayes
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                • #9
                  All your bass are belong to us.

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