We've praised bluetooth headbands before due to being a very low-cost option to listening to music unhindered in various situations. Also, we've used cheap bluetooth headbands to defeat the Havana syndrome at a bargain price.

For people that might be wondering about the battery, here are some details:

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Naturally, it is a very simple and elegant device that can be easily upgraded by adding a larger battery. The only impediment would be that the box holding the battery and the PCB are supposed to rest on the user's forehead such that there is not much space available.

Maybe in the future they'll produce bendable or foldable batteries.

Sometimes it happens that these headbands break and knowing Chinese mass-production, they are actually very easily fixed if you happen to have access to a solder iron. What happens is that due to the headbands being designed for comfort, the wires that are passed through the headband are very thin to not bother the wearer. From time to time, as the headbands are used, the user tends to pull on the wires and inner speakers in order to adjust the sound, which is something that can lead to the wires disconnecting from either the speakers or the PCB of the device.

The device is actually great, but due to these things being mass produced and offered at a very low cost, there is often not much time or funding for quality assessment to take place, such that the solder points are not always great. However, with a solder gun, this can be fixed and the device will really work forever.

It is tough to explain how this device is "disassembled" - the principle is that the device has a center box that is supposed to fit on the forehead and there are two wires leading to the speakers in the same direction, one wire longer than the other. The trick to removing the speakers and the box is to lightly push the box down and dislodge it from a small crib that it sits inside. Then, the box is minced slowly and pushed out alongside the first speaker, with the second speaker being pulled out from the other side. Of course, there is an opening at the back so the whole assembly can be taken out. It is also a good practice to pull out the assembly and wash the headband from time to time.

The box has a lid with small plastic struts and it is closed just through sheer pressure such that some care must be taken when opning the box. Ideally a thin margin like that of a pen-knife should do it and the knife should be slid in-between the slight opening and then the box can be gently split in two.

The typical routine for these devices is to open them up and check the solder points. In this particular case, one of the speakers, namely the one in the previous image to the right was pulled away such that one of the wires came loose and made intermittent contact. We went a little overboard with the solder such that you can observe some round blobs on both wires but it's mainly to increase mechanical resistance.

We did the same for the speakers, both of them had the connections reinforced with some extra solder. Note that the wires are also glued by default to the back of the speaker using some resin-like compound. Either way, we reinforced that glue as well by adding some hot-melt glue to the back on top of the resin.

Another idea is to drop some hot-melt glue on top of the PCB connections to ensure that the wires are not pulled out.

The device is easily repaired and the circuitry looks very small and tidy. If treated well, this device can last forever.