Here’s something we haven’t run across before. We’re familiar with proprietary battery shapes (we’re looking at you, digital camera manufacturers), or custom recharge connections (look of death directed toward cellphone manufacturers), but using electrical tricks to force AAA brand loyalty is a new one. It seems that’s exactly what is happening with [OiD’s] wireless headphones which were manufactured by Phillips.
The headphones take AAA sized batteries and can use either disposable or rechargeable varieties. There is a warning label advising that only Phillips brand rechargeables should be used, and sure enough, if you try a different brand the performance suffers both in charging time and in battery life. The original batteries are labelled as Nickel Metal Hydride at 1.2V and 550 mAh, which falls within common specs. But [OiD] noticed that there is an extra conductor in the battery compartment that makes contact with the sides of the battery case. Further inspection reveals that a reverse-biased diode makes contact through this conductor with a portion of the battery which has not been painted. This is not true with other brands, allowing the circuit to distinguish between OEM and replacements.
[OiD] shorted out that connection and immediately saw a performance boost from his replacement batteries. It’s hard to know exactly what’s going on here without a full schematic for the circuit, but we’d love to hear your speculation on this setup in the comments. Is this a low tech version of the identity chips that camera batteries sometimes hide?
If you are in the market for a nice pair of Hi-Fi headphones, it is not uncommon to to find price tags in the range of $300-$500. [Stacy] loves her music, but she had no desire to pay that high a price for a pair of good portable cans. Instead, she upgraded a set of cheap, knock-off headphones to near-audiophile quality for less than $50.
She starts off by explaining the technology behind the expensive headphones you see in stores, and why the sound quality is so much better. She says the orthodynamic drivers used in these products produce far better sound due to the placement of the voice coils, and their lack of delay when producing sound.
She found a pair of orthodynamic drivers for $30 and fit them into her knock-off headphones with a reasonable amount of effort. A bit of insulation and supporting plastic was added to ensure proper mounting of the drivers, then the headset was painted and reassembled.
[Stacy] claims that the end result is easily comparable to far more expensive headsets, especially when connected to a proper amplifier. If you are looking to step up your audio game on the cheap, here’s your chance.
One complaint we hear about often is ear-bud’s cables getting tangled within backpacks. [Andrew] was having this “spaghetti” wire problem, and also wanted to listen to his music with ear protection on – where ear-buds are usually uncomfortable. The latter problem is fixed by placing speakers inside of folding ear protectors, and the cable is managed with a 3.5mm disconnect.
For those who can’t make disconnect-able headphones but still suffer from tangled headphone wire, we recommend proper wrapping technique for your wire, and a small carrying pouch. With the combination of the two, we’ve never had a tangled cable.
The headphone remote for the third generation iPod shuffle has a special chip that identifies it to the iPod itself. [David Carne] posted an in-depth report about the process he used to reverse engineering that protocol. He’s discovered that the remote uses a peculiar signal to identify it as authentic when the device powers up. We’ve talked about Apple’s use of peripheral authorization before and it seems this is no different. [David] did manage to emulate the authentication using an ATmega88. If you’ve got a shuffle 3G sitting around this info will allow you to operate it with a microcontroller in your next project.
Wireless headphones can be a wonderful way to help clear up the clutter inherent in most desktop PC systems. However, after plugging a wall wart in, and the headphone jack into the computer, the number of wires used has actually doubled. After [Parker] found an old set of JVC 900 Mhz wireless headphones (and a generic 900MHz transmitter), he cracked open the case to see what he could do with them. Realizing that the transmitter used a 12V DC source, he powered it with an unused floppy connector (which provides +12V, +5V, and two ground lines). He also wired the audio-in line directly onto his sound card headers rather than feeding out a headphone jack to the back. He then wrapped the whole thing in plastic to prevent unwanted shorting and placed it back in his PC, leaving him with a very functional wireless system. Detailed photos after the break.
Continue reading “Internal Wireless Headphones”
Many people find themselves frustrated when working with headphones. The tiny coated wire can be a real pain to work with. They are so very very small, and usually coated. We generally just end up doing a quick “sand and tape” which just isn’t very high quality. [Alex] sent in some tips that can really help you get those repairs or modifications going.
With the recent announcement that the only controls for the Ipod shuffle will be on the headphones, many were let down. [James] has come to the rescue, showing that you can just solder new ear buds on the end of the wires. Though this may not be the perfect solution, especially if your cable gets damaged, at least you can get a little better sound. This is a great example of something to show kids. It’s not too difficult and teaches them that if we’re not happy with something, we can hack it.