Bluetooth Audio Adapter Hacked to Switch Off Amplified Speakers

bluetooth-audio-amp-auto-switch

This Bluetooth Audio Adapter is meant to connect a Bluetooth audio source (like a smartphone or tablet) to a speaker system with a plain old line-in connection. It has the ability to automatically connection when the Bluetooth device comes into range. Sounds convenient until [Andreas Pösch] points out that he still has to switch the speakers on and off manually. This hack automates the entire thing using a bit of additional hardware.

If you look closely you’ll see that the black cables have barrel jacks. This is a power pass-through rig that he whipped up. The protoboard includes a 7805 linear regulator which feeds power to the green circuit board in lieu of it’s original power adapter. A MOSFET switches outbound power headed for the speakers. All of it fits inside of the original enclosure, and he only had to add one port for the AC adapter.

This would be absolutely perfect for an antique radio retrofit. One of these adapters can be had for just over thirty bucks!

Comments

  1. kommune78 says:

    30 Bucks? Mine in a USB Stick shape was 5 Bucks and works like a charm both with Apple and Android Devices.

  2. fartface says:

    Or just build an audio activated switch. when audio is present close relay, ~30 seconds after audio goes away open relay. pretty darn easy with analog only components, even easier with a picaxe. And then it would work with any device.

    • Geebles says:

      Thats a bit more complicated that a single transistor as the guy has used. The BT device has an LED ‘connected’ light so linking that makes more sense (binary on/off when you want the amp on/off). I think that if you had to take the time to physically plug in your device to the aux, the power button ~1m away from it isn’t worth the effort of automating.. i would imagine that most wireless audio devices have a status led of sorts (certainly ‘connected’ is require to know your device is connected anyway!)

    • cde says:

      Won’t stop the speakers from buzzing.

  3. strider_mt2k says:

    “This is a power pass-through rig that he whipped up.”

    Why are you putting so much emphasis on the “H”?
    ;)

  4. BiOzZ says:

    is the regulator really necessary?

  5. prashant b.mulge says:

    how to amplify the sound (voice in headset) of Bluetooth headset

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