Saturday, August 27, 2011

Bluetooth Cassette Adapter

I've been looking for a new car recently and one feature that I really want is a sound system with Bluetooth connectivity. For ages I've played music in my truck from my phone using a cassette adapter but I hate dealing with the wires. Then inspiration struck. What if I had a cassette adapter with Bluetooth connectivity? Brilliant!

For a starting point I went to eBay and found a cheap pair of Bluetooth headphones for about $15

Opening up my old cassette adapter, this is what I found. The gear drive will need to be kept intact, otherwise the tape deck will think that the tape is at its end. Unfortunately this dramatically cut down the amount of space that I had to work with. Fitting everything into the cassette form factor was the biggest challenge of the project.

This is what the electronics of the headphones looked like after teardown. The electronics are pretty straight forward. I'll need to keep the PCB and the battery. To get the adapter to play through the tape deck I took the leads from the speakers and soldered them to the tape write head from the cassette adapter.

It looks like I got lucky. The Bluetooth PCB will fit along the side of the cassette without having to cut it down or move components. I cut out one corner of the cassette to make space for the mini USB port that is used to charge the device.

To mount the circuit board I cut out a slice in the cassette housing to hold one end and secured the other end with a tiny screw.

 Here is how I arranged the electronics in the cassette. There was just barely enough space, but everything fits, and the gear drive still works.


All that was left was tricky task of reassembling the cassette. Here is the final product. the button on the top is used to turn the system on and off.

The cassette adapter works great! The gear drive is more noisy than it used to be but if you are playing music you don't notice it. I've been driving around with my new adapter for a few days now. It seems like I get about 6-7 hrs of music time between charges. I had originally hoped to be able to charge while playing but the  design of the tape deck in my truck interferes with the cable. Anyway, I'm pretty happy with the results.

~Hovisbread


21 comments:

  1. i have a cassette adapter, i have that bluetooth headset, i have a truck w/ a cassette player, i have a project to occupy my time today.

    thanks.

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  3. I'm jealous... Might I ask what device your syncing it with.

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  4. It occurs to me that any vehicle with a line-in input can be adapted to connect to a bluetooth transceiver permanently installed, and hidden out of sight.

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  5. Now the next step would be to link the gear drive to a small generator to charge the battery.

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  6. Have you considered buying a spare battery pack and wiring it up to increase battery life by a fair amount?

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  7. I am super interested in this but Im not familiar with how to solder. Is there any way you would be able to make one for a fee if I sent the exact parts you need? I have both the headphones and a tape adapter.

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  8. lol, yo star! i'll help you out ;)

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  9. I have a Sony CPA-7 that I SPECIFCALLY want to use because it's the better of the Sony adapter series (the CPA-9 has no bass).

    How much for materials? Would you make one for someone?

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  10. Hi there!

    This hack touches exactly the matter I'm thinking of. The question is: shouldn't that be done with eliminating amplifier which drives the speakers? Correct me if I'm wrong, but what you get from this BT headset is amplified source signal. Does it cause any quality issues?

    Greets

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    1. Not really. The headphones were such small speakers, the power required to drive is very small. In fact, the audio out from the BT board was quieter than the original wired input.

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    2. I have a pair of those medium-sized logitech BT headphones that were likely to crack at the middle point of the headband. Actually, mine are cracked and collecting dust in a box. Could I simply remove the speakers and connect the outputs without messing with any amplification circuitry at all?

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  11. I just did this myself. I used a Coby BT receiver that I picked up at Frys for $10 and a XM cassette adapter. The cassette adapter is super thin plastic and has broken in a few spots, but it still works. I just tested it today and was surprised at how well it worked. I had been thinking about doing this for a couple of years, but didn't get around to it until last month.

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  12. What headphones did you use? I tried with some motorola s10 hd i had lying around but the board was too big... Also which wires did you wire up to the tape head? I have like 7 wires on each speaker

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  13. The headphones were Motorola. I don't remember the model number. You should only have 2 wires connected to each speaker. Are the extra wires perhaps leading to the control buttons?

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  14. yea I believe that is how it was. Do I unsolder the control wires from the board and only keep the speaker wires? And then do I solder the speaker wires where the cable wires went?

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  15. Do headphones have to be A2DP enabled, to have the cassette well paired with an iphone, or do any bluetooth headphones (4$ on ebay, sport style) work great for pairing? Furthermore, does the modified cassette need those white gears to be in. Thank you in advance. )

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    1. A2DP / BT 3.0 is required for audio (i.e. Android). BT 2.1 is just phone call audio. Don't get the old BT 2.x headsets.

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  16. While i agree it is a good idea to drive with a hands free device for your phone. "Oxi Bluetooth Over The Head Headset Noise Canceling Flexible Boom Microphone for all Cellphones and Iphones" is a good example of best headset for truckers it is easily available from http://www.amazon.com/gp/product/B00G3FZ7YU

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  17. After reading this post I got some very unique information which are really very helpful for anyone.
    visit http://www.ebay.com/itm/OXi-Bluetooth-Headset-With-Super-Noise-cancelling-Flexible-Boom-Microphone-/251535744477?ssPageName=STRK:MESE:IT


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