Bluetooth Sleeping Mask Upgrade Success! Moderators: adafruit_support_bill, adafruit

[DJDevon3]

I bought a ProCIV bluetooth sleeping mask on Amazon (2019 updated version) but it's barely audible at full volume. In the past I used 3.5mm corded sleeping masks which are plenty loud but the cord breaks eventually. So I tried to make my own louder version but so far have failed. I haven't used any parts from the ProCIV, still sleeping with it in the mean time as it's better than nothing.

I used the Adafruit 328 (2500 mAh) battery (made a small cardboard enclosure for it), Adafruit 259 Li-ion charger, and DWCT14+ bluetooth/amp module. Hooked it up to 2x 32 Ohm .25W speakers repurposed from an old 3.5mm corded mask (AGPTek) that had a broken cord.
PRO: Sound was very loud at half volume yey! DWCT14+ is cold to the touch while bluetooth is connected and idle.
CON: Gets distorted above half volume. DWCT14+ gets smoking hot even at low volume. As soon as music is played it starts heating up. Only listened to 30 seconds at a time because I know it'll fry if I allow it to run super hot. Will only run 30 seconds at a time before getting too hot to touch (no thermal protection?).

There's no way I would feel safe using that on top of a Li-ion battery in a tiny case on my forehead while sleeping. :/ I have a feeling the 32 Ohm speakers might be the cause of why the DWCT14 gets so hot but I don't know enough to say if that's true or not. I would rather buy an Adafruit module to use because I know they are very well engineered. The charger and battery are cold to the touch even while the DWCT14 was too hot to touch, that was actually impressive and one reason why I prefer Adafruit products.

I was looking at the TP2012 class D amp but it doesn't have bluetooth. I tried searching Adafruit's products but couldn't find something to fit my need. I don't really know what to do here. I just wanted a louder sleeping mask. The corded sleeping masks are plenty loud enough and I was very happy with them but the cord breaks eventually, went through 3 pairs of them before I bought the ProCIV mask and that one is barely audible. Just looking to make a louder bluetooth sleeping mask.

I suck at individual electrical components but can solder modules. Modules are very appealing for this project because they are low profile PCB's. Far better than I could make on a breadboard even if I knew how to design circuits. Looking for a bluetooth + amplifier module that is safe to use as a wearable so that I don't melt my face off when sleeping. :) Any advice on perhaps what I've done wrong and how to fix it would be greatly appreciated.

[adafruit_support_mike]

I'm afraid we don't have any Bluetooth audio devices. The protocol now known as Bluetooth Classic isn't friendly toward hackers, so scavenging boards from off-the-shelf products is the easiest way to get a receiver.

If the DWCT14+ is getting hot, it sounds like there's some kind of short circuit. 32-Ohm speakers shouldn't draw enough current from a LiPo supply to cause significant heating. Check for a weak solder bridge between the ROUT+ and ROUT- pins.

[DJDevon3]

Thank you for your advice! Wish Adafruit would carry something like that but if not I'm sure there is a reason for it.

Replaced the AGPTek headphone hair thin cable wires with 22 gauge wires. That did the trick. They were so thin I had to squint to solder a hair. Pretty sure the resistance built up. The new wires work great that's all it was!

While trying to figure out the problem I thought maybe there was something wrong with the board so I ordered some more stuff and umm now I have 2 lol. The one on the right is the better one, it's louder. However the one on the left is convenient to plug any headphone into. Been playing music on both of them for hours no problem. :)

Here's a price & component list in case anyone wants to know what was involved.

$14: AGPTek corded audio mask with 32 Ohm .25 Watt speakers
$09: DW-CT14+ Bluetooth Stereo Amplifier 2x5W
$23: Adafruit 259 Li-ion Charger
$16: Adafruit 328 3.7 2500maH battery
--------------------------------------------------------------------------------
$62 loud bluetooth sleeping mask with 45 hour battery life

Spent a lot on the project to get the comfort and volume that I wanted. Worth it. :)

[adafruit_support_mike]

You've pretty well summed up the whole idea behind Making: being able to make things exactly the way you want.

I'm glad to hear a change to the wiring fixed the problem. Happy hacking!

[DJDevon3]

:0 Thank you for your gracious comment. It's only because of these modules that the project was a success.

I might have gone overboard with the 2500mAh battery. It doesn't fit in the mask for sheer size. The PCB's are smaller than the battery. I can make it smaller with a smaller battery but I'd sacrifice battery life for it.

Fully charged and started playing music at 90% at 5pm on Saturday. It's now 1am Sunday and still going. Been listening to music non-stop as a test at full volume... no heat. Also the larger wires now don't distort until it's at about 75% volume. I think the 50% distortion was due to under driving, feels like I hit a sweet spot RMS of 75%. I can go to 100% with slight distortion. It's LOUD. :)

One off the biggest things that pissed me off about my ProCIV mask purchase was its advertised 8 hour battery life. It actually lasts about 4-5 hours (180mAh battery). It won't even last a single sleep cycle without turning off. SMH. Even if I gave it a bigger battery that would not have fixed the low volume issue. It might last 8 hours at 1% volume, pffft marketing lies.

One of the things I love about Adafruit, if you guys say something will do X then it does X. Your electrical engineering skills are inspiring and advertising integrity matters. That's why whenever I have a small electronics project I usually look to see if Adafruit has it first. You guys are awesome. Needless to say if you had what I needed I would have purchased it in a heartbeat. Ideally, I'd love to see bluetooth amplifier boards that match different sized Li-ion battery sizes for project boxes so people can make their own and break out of this stupid cycle of broken headphones.

Looked on Amazon trying to compare what I made with commercial headphones to see where my creation stands... most of the bluetooth headphones that have a 30 hour battery life are around $50-$70 and headphones with a 40 hour battery life are about $80-$100+. Mine has some low frequency limitations of the small speakers (around 40Hz) but I'm not trying to make headphones in the traditional sense. In terms of sleeping masks there is no comparison to what I made.

I completely dissected my broken Logitech G930's during the brainstorming phase to get a little insight and know how they take a tiny $10 speaker and make it so loud. It's a dual diaphragm trick using the housing as a ported chamber that has more rubber in it which produces more waves like any diaphragm. Brilliant engineering trick. I also used the G930's for years for music production they have amazing bass response, true 25Hz bass, and a 600mAh battery. They are RF and have horrible issues with signal dropout, recharging, and breaking in every way possible. I went through 3 of those too. I was living in a broken headphone hell. Oddly enough my new bluetooth mask beats the G930 in range and signal stability. Weird! The G930's are RF and supposed to have longer range but they don't. The more I use my new mask the more I love it.

I feel completely justified with how much I spent on components to create what I have now. It's wireless, loud, 30+ hour battery life, can sleep with it on. Done with commercial headphones and sleeping masks. This is good enough to serve both roles for my needs. Well except music production I do have another pair of headphones for that. I want to make it smaller but I don't want to give up the 30+ hours of battery life lol. A good problem to have. :)

I'll take pics of the finished version when the battery finally dies after the initial test, still over 30+ hours. Will show the guts of it all and final wire routing.

Thank you to Adafruit and all the PCB module makers out there. You are doing truly great things so that people like me can make things easily without an engineering degree. You are the backbone to a world of electronic creativity. You help people make what might have been previously impossible daydreams, now possible. <3

[DJDevon3]

With my real world use experience the ProCiv bluetooth mask (180mAh) lasts 5 hours and the Logitech G930's (600mAh) lasts 8 hours. Naturally I thought the real world difference between 5 hours and 8 hours was the difference of 420mAh. I was confused about battery selection so I went for the big one, 2500mAh. Realistically I was shooting for 18-20 hours in a best case scenario, having no idea what my load characteristics would be.

DWCT14+ finally started beeping with low battery indicator almost exactly at the 47 hour mark. That was twice what I'd hoped. I'm overjoyed with the performance. It never got warm and never disconnected. If I could ignore the low battery beeps every 30 seconds it probably could have made it to the 48 hour mark.

47 HOURS LATER...

[DJDevon3]

Here's the finished project. Still have to play with the wire length. Included a really rough sketch and dimensions if anyone wants to make one.

Pros: Louder than commercially available masks. 40+ hour battery life. Comfortable enough to sleep on.
Cons: Need a big mask to center mount. No buttons for play/pause/next/previous. Volume and track selection controlled by transmitter (smartphone).

I didn't want a mask with a microphone. Being woken up and forced to talk in a sleepy state I dislike, to me that is actually a good thing. However, you can add one to the DWCT14+ if you want. Not having track or volume control isn't a big deal to me either since it's a sleeping mask. Set a looped playlist, volume, and go unconscious in peace.

Did I mention it has a 40+ hour battery life. I still can't believe it. :)

[DJDevon3]

So I finished up the 2nd bluetooth mask. This one only uses a JDY-64 module. I didn't want to waste my Adafruit 1000C boost charger and couple it on the board. So I'm charging it separately for now and throwing it back in the mask. Ordered another Adafruit 259 charging module that I'll couple to this one instead.

It's center mounted but doesn't work at all as a sleeping mask. Even though this version is smaller than my first one the center mounted box is still too large and allows light to come in. It's because the CozyPhones mask is much narrower than the AGPTek mask. The center band is far too narrow. These are more for sports wear, jogging stuff, and the whole thing where people go outside and walk around yeah it's not for me. Maybe someone else will have a use for them.

Definitely lower profile which I liked. The audio quality of the JDY-64 is loud but with signal distortion and lacks signal stability at ranges where the DWCT14 works perfectly. The 3.5mm audio jack is very convenient and has tactile button controls though they're really tiny and almost impossible to use (needs bigger button overlay or desolder and create a control panel PCB with bigger buttons). One really nice feature is that it does have independent volume control (digital potentiometer) apart from the smartphone volume... however it still produces background noise I can only describe as Borg like with garbled harmonics. If you're looking for a quality bluetooth module I'd skip this one in favor of the DWCT14. :/

Used with Adafruit 2000mAh battery so I'm just going to guess this thing will run for 30 hours compared to my other mask. Not even going to bother testing it because the audio quality isn't worth listening to for that long. I might end up giving this one away to someone as a free gift. Might be useful to someone who likes to sleep with white noise where noise is actually appreciated. For music this one is average. Not horrible but not very good either.

Regardless of all the nice features if audio quality isn't good then it's not a good bluetooth audio module. This module exceeds in all the unimportant areas and is underwhelming in all the important areas.

$18 CozyPhones corded sleeping mask
$10 JDY-64 modules (2 pack)
$15 Adafruit 2000mAh battery
------------------------------------------------------------
$43 bluetooth CozyPhones

[adafruit_support_mike]

Looking good! Thanks for the build photos!

[AnneBarela]

Adafruit will have a blog post about your project up about 9 am EDT today
https://blog.adafruit.com/2019/03/13/fr ... bluetooth/

Well done!

[DJDevon3]

Very cool! That must have been posted while I was still running the initial test because the final result with the 2500mAh mask was exactly 47 hours not 30. I think a 17 hour difference in play time is worth updating that blog post. ;)

Billy Mays here! But wait there's more! I'm now on my 3rd mask build.
Mask 1: AGPTek conversion used a 2500mAh battery and ran for 47 hours but is heavy and bulky. Still comfortable enough to sleep with. :)
Mask 2: CozyPhones conversion used a 2000 mAh battery. Still too big to center mount. Poor audio quality from that BT module.

Introducing Mask #3: I purchased a brand new AGPTek corded mask and immediately hacked it to pieces. After building mask # 2, I purchased a variety of different speakers to experiment with. I've become much better with Ohm's Law because of this project but when sellers lie about their product specs, erase markings from speakers and intentionally relabel them to be more powerful than they are just to sell more units then things become problematic. I had to actually start testing the resistance of every speaker because I didn't know what to trust anymore.

The DWCT14+ description says it works best with 2 to 8 Ohm 3-10W speakers. For headphones it works best with 32 Ohm .25W or .50W speakers. It's a matter of distance. You wouldn't want 10W earbuds right? The closer to the ear the speaker is the less power it requires to produce the same appreciable volume.

Had a hard time finding the right size project box. I don't have a 3D printer. Actually kind of proud I stuffed everything in that tiny box. It's a tighter fit than it looks. Mask 3 is what I set out to create from the start but it took a couple revisions to get there. I'll update this with a quasi schematic of the new box but it's the same exact components just in a smaller case with a 1500 mAh battery. The difference in case size vs battery life for a sleeping mask is a delicate balance, a design choice that isn't easy to make. The only way I could shrink the project case down was to go with a smaller battery. The case size is almost purely dependent on the battery size and a 2500 mAh is pretty big. A 1500 mAh offers a slightly smaller footprint. The difference between a 2000 mAh footprint and 2500 mAh footprint isn't that much different but a 1500 mAh is enough to matter. It's not going to be a 40+ hour headphone but it's the most comfortable and compact one I've created so far. It also has a switch which I hooked up only to the load. I can turn off the DWCT14+ when it starts beeping due to low battery or charge the battery without any load, with the flip of a switch.

[adafruit_support_mike]

I purchased a brand new AGPTek corded mask and immediately hacked it to pieces.

Yep, that's a "you might be a Maker if" moment: buying things specifically to take them apart and use the pieces.

Mask 3 is what I set out to create from the start but it took a couple revisions to get there.

That's also stereotypical. The first couple of times you build a project, you're really learning what you want to make. You start the first version with a mental image of the end product, but you have to work with the pieces to figure out how to make that picture work in hardware.

[DJDevon3]

Thank you Mike for the positive encouragement and Adafruit for including me in a blog post. I'm very thankful for having companies out there like Adafruit that create modules that can be put together in almost unlimited ways and the support forums that help people with their project ideas. Adafruit has a vibrant and creative community atmosphere. I know Adafruit isn't the only company out there but it's certainly the most well respected and prolific within the maker space for all the right reasons.

After laying down for the night with mask # 3 immediately noticed a design problem. The narrow mask band with a large center mounted box feels like you're sleeping with a block of wood on the bridge of your nose. I uhhh, didn't think about that. Also light leaks in because the mask no longer contours to your face. The box is as small as I can possibly make it but it's still too big to be mounted in narrow banded lycra masks. Center mounting to an AGPTek mask is a mistake, same mistake as the CozyPhones mask #2. :/ This wasn't a problem with mask # 1 because it was temple mounted. I plan on temple mounting mask #3 now. It should be even more comfortable than mask #1 with its smaller footprint.

The problem with the lycra masks such as AGPTek or CozyPhones is the center band not being tall enough because they were 3.5mm corded masks which is plenty for their original intent. To add a small battery box you need something taller like the ProCIV. The lycra masks are only tall enough to cover your eyes so putting a box there means having a box directly in front of your eyes, on the bridge of your nose and not on the forehead where it should be. The problem with the ProCIV is material thickness, stuffing, low volume driven by a 180mAh battery. ProCIV also barely reaches my ears, it has a lot of physical design issues. It's looks nice but looks don't help you fall asleep at night.

So why don't I take my electronics and put them in the ProCIV? Because the ProCIV has physical design issues apart from electronic issues.

So I said screw it and ordered some lyrca, mesh, and velcro. Going to attempt to sew my own. I don't know how to sew. I'm sure my first attempts will not turn out well but isn't learning as you go kind of the whole point of... everything in life? Mistakes will be made.

Looking on the bright side. I now have 4 bluetooth sleeping masks to rotate through for different uses. Never having to worry about breaking headphone bands, hinges, or ripping a cord out from an office chair. If well taken care of they will last me for years without issue and since they are modular if something fails I can replace it. They're only made with 4 components. A li-ion battery, charger module, bluetooth module w/ amplifer, and speakers.

[adafruit_support_mike]

I don't know how to sew.

That's where everyone starts, for any skill.

I make a point of watching this video at least once a month, just to keep it fresh in my mind:

https://www.youtube.com/watch?v=rDjrOaoHz9s

The title is 'Fail Faster'.

[DJDevon3]

Failing fast is what this project was all about. Quick prototyping into tangible results was very satisfying, even if they were fails. Learning what not to do is part of the process. I think Edison said something famous about that. I haven't failed, just finding ways not to do it the right way. :)

Ran into an unexpected issue of RF shielding from the cables. The powered loop from the 22 gauge solid core wire around the forehead to drive the magnetic voice coils is screwing with my equilibrium. Like homing pigeons, some humans are in fact sensitive to magnetic fields, an unexpected discovery. It uh might cause dizziness. Maybe it's not the wiring but the bluetooth antenna on my forehead l don't know.

Now I'm trying to find RF shielded braiding small enough. Maybe I should swap it out for braided wire instead of solid core? I'm a car guy it's what I had laying around ok. :P

Was surprised to find some sleeping mask teardown videos by Adafruit on YouTube. That was really cool, I learned a lot about mask design. Oh this isn't over yet. Still more failing to do. :)