Adding a bluetooth audio input to my car stereo for <$15. Phase 1: research and experimentation.
Friday, July 9th, 2010I noticed that DealExtreme sells a bluetooth stereo music receiver for $12.992. This tiny, battery-operated device looks like an ugly cousin of an old iPod shuffle, sporting a big bluetooth symbol in the middle of its control pad. It’s designed to accept wireless transmissions from your iPhone, computer, or other device that supports bluetooth audio streaming, and then play that received audio out headphones connected to its jack. $12.99 falls well within my speculative hacking budget.
So I bought the device and have tested it out. When I plugged a cable between its headphone jack and my car’s audio input jack and streamed audio to it from my iPhone, it worked a treat. It shows up in the iPhone’s bluetooth menu as a device named,”BCK-08″.
There are a few problems. The device’s built-in battery is pathetic, and within an hour or two of use it begins to beep every few minutes to indicate that the battery needs a charge. I also think the audio quality decreases in direct proportion to the battery’s charge, but am not positive about that.
My goal is to take apart this device, wire it to be powered directly from my car, and leave it permanently connected to the car stereo’s auxiliary input jack.
I’ve found a few resources on the net that may be of help:
- The data sheet for the chip used in this device, the ISSC IS1621N. I wish this PDF file were available to simply download. To have to view it in a flash-based viewer feels archaic, and overprotective for information the manufacturer should want to widely disseminate. I do see a button labeled “download” (in Chinese), but to download requires an account on the website and I don’t feel like jumping through account creation hoops in Chinese right now3.
- A page about the chip at its manufacturer’s website.
- The page of someone who has already taken apart the BCK-08 and is planning to do a similar project. He mentions a desire to get line-level output from the device. I think that’d be nice, though I notice no mention of a line out in the chip’s pinout, only an amplified headphone out.
- Wikipedia’s writeup of the LM317 adjustable voltage regulator, which is probably the part I’ll need to use to take my car’s 12V as input and supply 3.7V DC to the BCK-08.
- Or perhaps I could use this constant current-regulated LED driver4 to bring my car’s 12V down to 3.7V. It’s designed for high-power Cree LEDs, which take 3.7V input, so I’d guess it might be about right. Would save me some time designing my own circuit with the LM317, and it only costs $2.39.
- I’m sure many other cars also have this feature. [↩]
- The device’s full name on DealExtreme’s site is “Bluetooth 2.0 A2DP AVRCP Stereo Music Receiver and Handsfree (Black)” [↩]
- I’ve been out of China for 3 years now and don’t feel like spending an hour fighting my way through the website with a dictionary in hand [↩]
- Also from DealExtreme –how about that? [↩]














